Is that science which teaches us the properties of mineral bodies, and by which we learn how to characterize, distinguish, and classify them into a proper order.
Mineralogy seems to have been in a manner coeval with the world. Precious stones of various kinds appear to have been well known among the Jews and Egyptians in the time of Moses; and even the most rude and barbarous nations appear to have had some knowledge of the ores of different metals. As the science is nearly allied to chemistry, it is probable that the improvements both in chemistry and mineralogy have nearly kept pace with each other; and indeed it is but of late, since the principles of chemistry were well understood, that mineralogy hath been advanced to any degree of perfection. The best way of studying mineralogy, therefore, is by applying chemistry to it; and not contenting ourselves merely with inspecting the outsides of bodies, but decomposing them according to the rules of chemistry. This method hath been brought to the greatest perfection by Mr Pott of Berlin, and after him by Mr Cronstedt of Sweden. To obtain this end, chemical experiments in the large way are without doubt necessary; but as a great deal of the mineral kingdom has already been examined in this manner, we do not need to repeat all those experiments in their whole extent, unless some new and particular phenomena should discover themselves in those things we are examining; else the tediousness of those processes might discourage some from going farther, and take up much of the time of others that might be better employed. An easier way may therefore be adopted, which even for the most part is sufficient, and which though made in miniature, yet is as scientific as the common manner of proceeding in the laboratories, since it imitates that, and is founded upon the same principles. This consists in making the experiments upon a piece of charcoal with the concentrated flame of a candle blown through a blow-pipe. The heat occasioned by this is very intense; and the mineral bodies may here be burnt, calcined, melted, and scorified, &c. as well as in any great works.
A pocket-laboratory containing all things necessary for trying mineralogical experiments is represented, Plate CLXXXI. fig. 1. with the case, exactly of the form, bigness, and proportions as that made use of by Mr Cronstedt; what alterations there may be wanted are easily found out by practice.
a, b. Are the two parts of which the Blow-Pipe consists, and which are already described under that article.
a. A wax-candle, destined to be made use of, particularly in travelling, when no other candle is to be had. Apparatus.
Method of making Experiments.
A pair of nippers, to handle so much the easier these things which are to be tried, because they are generally small particles: this serves also to touch and turn the subjects during the experiments, when they are hot and could not be well handled with the fingers.
d, e, f. Are three phials, to put the required fluxes in, viz. borax, the mineral alkali sal soda), and sal fusible microcofunicum.
g. A hammer, to break any part of a stone, when it is to be tried: this serves also to pound things with.
i. A magnifying-glass, necessary when the objects are too small to be seen by the naked eye.
k. A steel to strike fire, by which the hardness or softness of the bodies is tried.
l. A loadstone, to discover the presence of iron.
m. A file, wherewith to distinguish natural gems, quartz-crystals, and artificial or coloured glasses, from one another.
n. A thin square plate made of tempered steel, filed flat on one side, to pound things upon, and polished on the other side to hammer metals upon.
Above this steel plate n, and within the circle drawn round about it, is the place for a candlestick. This candlestick is shown in plan, fig. 2, and in profile, fig. 3. It consists of a round brass plate; the point s, and the ring b round it, is instead of the socket in another candlestick, which would here take up too much room.
Fig. 4, is a thin iron ring, a sixth part of an inch high; within this ring the pounding and grinding of the things upon the steel plate, fig. 1, n, is performed, that they may not be lost. In packing up, this ring is to be put loose upon the candlestick; and, as it is lower than the point of this, it does not take up much room in the case.
The whole case thus made, with all the instruments in it, is no more than one and an eighth part of an inch high, and consequently not more troublesome to be carried in the pocket than a small book.
The pocket-laboratory here described, and the box for the acids, to be afterwards mentioned have been improved after the manner of Mr Cronstedt, by a gentleman particularly acquainted with Mr Engstrom, from whom he learned this method of making mineralogical experiments. The bulk of the first has been reduced nine and a half cubic inches; its length being diminished one sixteenth of an inch, the breadth five and the depth two; notwithstanding which, there is also added a piece of charcoal for trying the experiments, a flint, a piece of agaric tinder, and some matches for lighting the candle. The three phials n m v for the salts, are of different colours, to prevent any mistake. The candlestick has different concentric grooves for keeping the results of the trials separate. The blow-pipe s b has a silver mouth-piece, and screws in the middle of the ball, in order to clean out the moisture with the greater ease; and the small wire (Plate CLV. fig. 2. n° 1.) is more conveniently detached than fixed round it. The other box for the acids, is reduced to less than a fourth of its original bulk, being exactly of the same size with the above. It contains two small matrasses (fig. 4.) for making solutions; a trough (fig. 5.) for washing the ore after its being pounded; and the three small bottles with double stoppers, for the nitrous, muriatic, and vitriolic acids, have their respective initials cut on each.
Both these pocket-laboratories, made in the neatest manner by an ingenious artist, may be had ready furnished with the purest acids, &c., at the General Office of Business, Arts, and Trade, No. 98, Wood-street, Cheapside.
Whenever anything is to be tried, one must not begin immediately with the blow-pipe; some preliminary experiments ought to go before, by which those in the fire may afterwards be directed. For instance, a stone is not always homogeneous, or of the same kind throughout, although it may appear to the eye to be so: the magnifying-glass is therefore necessary, to discover the heterogeneous particles, if there be any; and these ought to be separated, and every thing tried by itself, that the effects of two different things tried together, may not be attributed to one alone. This might happen with some of the finer mica, which are now and then found mixed with small particles of quartz, scarcely to be perceived by the eye. The trapp (in German schwartzstein) is also sometimes mixed with very fine particles of feltspat (spatium scintillans), or of calcareous spar, &c. After this experiment follows that to try the hardness of the stone in question with the steel. The flint and garnet kinds are commonly known to strike fire with the steel; but there are also other stones, though very seldom, found so hard as to strike fire: a kind of trapp is found of that hardness in which no particles of feltspat are to be seen. Coloured glasses resemble true gems; but as they are very soft in comparison to these, they are easily discovered by means of the file: the common quartz-crystals are harder than coloured glasses, but softer than the gems. The loadstone discovers the presence of iron, when it is not mixed in too small a quantity in the stone, and often before the stone is roasted. Some kinds of hematites, and particularly the corulecens, is very like some other iron ores; but distinguishes itself from these by a red colour when pounded, and others giving a blackish powder, and so forth.
To manage the blow-pipe with ease requires some practice. A beginner blows generally too strongly, which forces him to take breath very often, and then he draws the flame at the same time along into the blow-pipe: this is troublesome for himself, and the experiment cools always a little at the same time. But the more experienced can breathe in through the nose, and yet at the same time blow through the pipe, whereby a constant flame from the candle is kept up. The whole art consists in constantly taking in air through the nose, and with the tongue moderating its blowing out; so that the tongue performs nearly the office of a sucker in a pump; or rather, the action of the nose, lungs, and mouth, resembles here the action of bellows with double partitions. In this manner there is no need of blowing violently, but only with a moderate and equal force; and thus the breath can never fail the operator. The only inconvenience attending it is, that the lips grow weak or tired, after having continued to blow for a while in one strain; but they soon recover their former strength by ceasing to blow for some minutes. The candle used for this purpose ought to be snuff-making often, but so that the top of the wick may retain some fat in it, because the flame is not hot enough when the wick is almost burnt to ashes; so that only the top must be snuffed off, because a low wick gives too small a flame. The blue flame is the hottest; this ought therefore to be forced out when a great heat is required, and only the point of the flame must be directed upon the subject which is to be effayed.
The piece of charcoal made use of in these experiments must not be of a disposition to crack. If this should happen, it must gradually be heated until it does not crack any more, before any effay is made upon it. If this be not observed, but the effay made immediately with a strong flame, small pieces of it will split off in the face and eyes of the effayer, and often throw along with them the matter that was to be effayed. Charcoal which is too much burnt consumes too quickly during the experiment, leaving small holes in it, wherein the matter to be tried may be lost; and charcoal that is burnt too little catches flame from the candle, burning by itself like a piece of wood, which likewise hinders the process.
Of those things that are to be effayed, only a small piece must be broke off for that purpose, not bigger than that the flame of the candle may be able to act upon it at once, if required; which is sometimes necessary; for instance, when the matter requires to be made red-hot throughout. A piece of about an eighth part of an inch square is reckoned of a moderate size, and fitted for experiments; seldom more, but rather less. This proportion is only mentioned as a direction in regard to the quantity, the figure being of no consequence at all, a piece broke off from a stone seldom or never happening to be square. But here it is to be observed, that the piece ought to be broke as thin as possible, at least the edges: the advantage thereof is easily seen, the fire having then more influence upon the subject, and the experiment being quicker made. This is particularly necessary to be observed when such stones are to be effayed, which, although in some respects fusible by themselves, yet resist considerably the action of the fire; because they may by these means be brought into fusion, at least at their edges, which else would have been very difficult if the piece had been thick.
Some of the mineral bodies are very difficult to keep ready upon the charcoal during the experiment, before they are made red-hot; because, as soon as the flame begins to act upon them, they split asunder with violence, and disperse. Such often are those which are of a soft consistency, or a particular figure, and which preserve the same figure in however minute particles they are broke; for instance, the calcareous spar, the sparry gypsum, (sparry fluor, white sparry lead-ore, the potters ore, (galena tessellata), the tessellated mock-lead or blends, &c. even all the common fluors which have no determinate figure, and most of the minerals metalliferous crystallifluate or spatose: all these are not so compact as common hard stones; and therefore, when the flame is immediately pushed at them, the heat forces itself quickly through and into their clefts or pores, and causes this violent expansion and dispersion. Many of the clays are likewise apt to crack in the fire, which may be for the most part ascribed to the humidity, of which they always retain a portion. Besides those enumerated, there may be found now and then other mineral bodies of the same quality.
The only way of preventing this inconvenience, is to heat the body as slowly as possible. It is best first of all to heat that place of the charcoal where the piece is intended to be put on, and afterwards lay it thereon; a little crackling will then ensue, but commonly of no great consequence. After that, the flame is to be blown very slowly towards it, in the beginning not directly upon, but somewhat above it, and so approaching nearer and nearer with the flame until it becomes red-hot. This will do for the most part; but there are nevertheless some substances which, notwithstanding all these precautions, it is almost impossible to keep on the charcoal. Thus the fluors are generally the most difficult; and as one of their principal characters is discovered by their effects in the fire per se, they ought necessarily to be tried that way. To this purpose it is best to make a little hole in the charcoal to put the flour in, and then to put another piece of charcoal as a covering upon this, leaving only a small opening for the flame to come in at, and to look at the proof. As this stone will nevertheless mostly split and fly about, a larger piece thereof than is before-mentioned must be taken, in order to have at least something of it left.
But if the experiment is to be made upon a stone whose effects one does not want to see in the fire per se, but rather with fluxes, then a piece of it ought to be forced down into melted borax, when always some part of it will remain in the borax, notwithstanding the greatest part may sometimes fly away by cracking.
As the stones undergo great alterations when exposed to the fire by themselves, whereby some of their characteristics, and often the most principal, are discovered, they ought first to be tried that way; observing what has been said before concerning the quantity of the matter, direction of the fire, &c. The following effects are generally the results of this experiment, viz:
1. Calcareous earth or stone, when it is pure, does never melt by itself, but becomes white and friable, so as to break freely between the fingers; and, if suffered to cool, and then mixed with water, it becomes hot, just as common quick-lime. As in these experiments only very small pieces are used, this last effect is best discovered by putting the proof on the outside of the hand, with a drop of water to it, when instantly a very quick heat is felt on the skin. When the calcareous substance is mixed with the vitriolic acid, as in the gypsum; or with clay, as in the marle; it commonly melts by itself; yet more or less difficulty in proportion to the differences of the mixtures: the gypsum produces generally a white, and the marle a grey glass or flax. When there is any iron in it, as in white iron ore, it becomes dark, and sometimes quite black, &c.
2. The siliceae never melt alone, but become generally more brittle after being burnt: such of them as are coloured become colourless, and the sooner when it does not arise from any contained metal; for instance, the topazes, amethysts, &c. some of the precious stones, however, excepted. And such as are mixed with a quantity of iron grow dark in the fire, as some of the jaspers, &c. Apparatus.
3. The garnet-kind melt always into a dark flag; and sometimes so easily, that it may be brought into a round globe upon the charcoal.
4. The argillaceæ, when pure, never melt, but become white and hard; the same effects follow when they are mixed with phlogiston; for instance, the soap-rock is easily cut with the knife; but, being burnt, it cuts glass, and would strike fire with the steel, if as large a piece as is necessary for that purpose could be tried in this way. The soap rocks are sometimes found of a dark brown and nearly black colour, but become white in the fire, as a piece of China ware; however, care must be taken not to push the flame from the top of the wick, there being for the most part a footy smoke, which commonly will darken all that it touches; and if this is not observed, a mistake in the experiment might easily happen: but if it is mixed with iron, as it is sometimes found, it does not so easily part with its dark colour. The argillaceæ, when mixed with lime, melt by themselves, as above-mentioned. When mixed with iron, as in the boles, they grow dark or black; and if the iron is not too great a quantity, they melt alone into a dark flag: the same happens when they are mixed with iron and a little of the vitriolic acid, as in the common clay, &c.
5. The micaceous and asbestos become somewhat hard and brittle in the fire, and are more or less refractory, though they give some marks of fusibility.
6. The fluors discover one of their chief characteristics by giving a light, like phosphorus, in the dark, when they are slowly heated; but lose this property, as well as their colour, as soon as they are made red-hot: they commonly melt in the fire into a white opaque flag, though some of them not very easily.
7. Some sorts of the zeolites, a stone lately discovered, melt easily and foam in the fire, sometimes nearly as much as borax, and become a frothy flag, &c.
8. A great many of those mineral bodies which are impregnated with iron, as the boles, and some of the white iron ores, &c. as well as some of the other iron ores, viz. the bloodstone, are not attracted by the loadstone before they have been thoroughly roasted, &c.
After the mineral bodies have been tried in the fire by themselves, they ought to be melted with fluxes, to find out if they can be dissolved or not, and some other phenomena attending this operation. To this purpose three different kinds of salts are used as fluxes, viz. sal soda, borax, and sal fusible microcosmicum.
The sal soda is not much used in these small experiments, its effects upon the charcoal rendering it for the most part improper; because, as soon as the flame begins to act upon it, it melts instantly, and is almost wholly attracted by the charcoal. When this salt is employed to make any experiment, but a very little quantity thereof is wanted at once, viz. about the cubic contents of an eighth part of an inch, more or less; this is laid upon the charcoal, and the flame blown on it with the blow-pipe; but as this salt commonly is in form of a powder, it is necessary to go on very softly, that the force of the flame may not disperse the minute particles of the salt. As soon as it begins to melt, it runs along on the charcoal almost as melted tallow; and when cold, it is a glassy matter of an opaque dull colour spread on the coal. The moment it is melted, the matter which is to be tried ought to be put into it, because otherwise the greatest part of the salt will be soaked into the charcoal, and too little of it left for the intended purpose; the flame ought then to be directed on the matter itself, and if the salt spreads too much about, leaving the proof almost alone, it may be brought to it again by blowing the flame on its extremities, and directing it towards the subject of the experiment. In the essays made with this salt, it is true, we may find if the mineral bodies which are melted with it have been dissolved by it or not; but we cannot tell with any certainty whether this is done hastily and with force, or gently and slowly; whether only a leas or a greater part of the matter has been dissolved; nor can it be well distinguished if the matter has imparted any weak tincture to the flag; because this salt always bubbles upon the charcoal during the experiment, nor is it clear when cool; so that scarce any colour, except it be a very deep one, can be discovered, although it may sometimes be coloured by the matter that has been tried.
The two other salts, viz. the borax, and the sal fusible microcosmicum, are very well adapted to these experiments, because they may by the flame be brought to a clear uncoloured and transparent glass; and as they have no attraction to the charcoal, they keep themselves always upon it in a round globular form. The sal fusible microcosmicum is very scarce, and not to be met with in the shops; it is made of urine. For its preparation, see Chemistry, n° 308.
The quantity of these two salts required for an experiment is almost the same as the sal soda; but as these salts are crystallized, and consequently include a great deal of water, particularly the borax, their bulk is considerably reduced when melted, and therefore little more may be taken than the before-mentioned quantity.
The borax and microcosmic salt, when exposed to the flame of the blow-pipe, bubble very much and foam before they melt to a clear glass; but more so the borax, which for the most part depends on the water they contain; and as this would hinder the essayer to make due observations on the phenomena of the experiment, the salt which is to be used must first be brought to clear glass before it can serve as a flux; it must therefore be kept in the fire until it is become so transparent that the cracks in the charcoal may be seen through it. This done, whatsoever is to be tried, is put to it, and the fire continued.
Here it is to be observed, that for the essays made with any of these two fluxes on mineral bodies, no larger pieces of these must be taken than that all together they may keep a globular form upon the charcoal; because then it may be better distinguished in what manner the flux acts upon the matter during the experiment: if this is not observed, the flux, communicating itself with every point of the surface of the mineral body, spreads all over it, and keeps the form of this salt, which commonly is flat, and by that means hinders the operator to observe all the phenomena which may happen. Besides, the flux being in too small a quantity, in proportion to the body to be tried, is too weak to act with all its force upon it. The best proportion, therefore, is about a third part of the mineral body to the flux. And, as the quantity of the flux (21, 23) makes a globe of a due size, in regard to the greatest... Method of greatest heat that it is possible to procure in these experiments, the size of the mineral body (8) required when it is to be tried in the fire by itself, is too large on this occasion, the third part of it being here almost sufficient.
The sal soda, as has been said before, is not of much use in these experiments; nor has it any particular qualities in preference to the two last-mentioned salts, except that it dissolves the zeolites easier than the borax and the sal fusibile microcofunicum.
This last-mentioned salt shows almost the same effects in the fire as the borax; and differs from this in very few circumstances, of which one of the principal is, that, when melted with manganese, it becomes of a crimson hue, instead of a jacinth colour, which borax takes.
This salt is, however, for its scarcity, still very little in use, borax alone being that which is commonly used. Whenever a mineral body is melted with any of these two last mentioned salts, in the above-described manner, it is easily seen whether it is quickly dissolved; because in that case an effervescence arises, which lasts till the whole is dissolved; or whether this is slowly done, in which case few and small bubbles only rise from the matter: likewise, if it cannot be dissolved at all; because then it is observed only to turn round in the flux without the least bubble, and the edges look as sharp as they were before.
In order further to illustrate what has been said about these experiments, we shall mention some instances concerning the effects of borax upon the mineral bodies, viz.
1. The calcareous substances, and all those stones which contain any thing of lime in their composition, dissolve readily, and with effervescence, in the borax: this effervescence is the more violent, the greater the portion of lime contained in the stone. This, however, is not the only reason in the gypsum, because both the constituents of this do readily mix with the borax, and therefore a greater effervescence arises in melting gypsum with the borax than lime alone.
2. The siliceous do not dissolve, unless some few, which contain a quantity of iron.
3. The argillaceous, when pure, are not acted upon by the borax; but when they are mixed with some heterogeneous bodies, they are dissolved, though very slowly; such is, for instance, the stone marrow, the common clay, &c.
4. The granate, zeolites, and trapp, dissolve but slowly.
5. The fluors, asbestos, and micaceous, dissolve for the most part very easily; and so forth.
Some of these bodies melt to a colourless transparent glass with the borax; for instance, the calcareous substances when pure, the fluors, some of the zeolites, &c. Others tinge the borax with a green transparent colour; viz. the granate, trapp, some of the argillaceous, some of the micaceous and asbestos: this green has its origin, partly from a small portion of iron which the granate particularly contain, and partly from phlogiston.
The borax cannot dissolve but a certain quantity of a mineral body proportional to its own. Of the calcareous kind it dissolves a vast quantity; but turns at last, when too much has been added, from a clear, transparent, to a white opaque flag. When the quantity of the calcareous matter exceeds but little in proportion, the glass looks very clear as long as it remains hot; but as soon as it begins to cool, a white half opaque cloud is seen to arise from the bottom, which spreads over the third, half, or more of the glass globe, in proportion to the quantity of calcareous matter; but the glass or flag is nevertheless shining, and of a glaify texture when broke: if more of this matter be added, the cloud rises quicker and more opaque, and so by degrees till the flag becomes quite milk-white: it is then no more of a shining, but rather dry appearance, on the surface; is very brittle, and of a grained texture when broke.
All that has been said hitherto of experiments upon mineral bodies, is only concerning the stones and earths. We now proceed to the metals and ores, in order to describe the manner of examining these bodies, and particularly the management of the blowpipe in these experiments. An exact knowledge and nice proceeding are so much the more necessary here, as the metals are often so much disguised in their ores as to be very difficultly known by their external appearance, and liable sometimes to be mistaken one for the other: some of the cobalt ores, for instance, resemble much a pyrites arsenicalis; there are also some iron and lead ores which are nearly like one another, &c.
As the ores generally consist of metals mineralised with sulphur or arsenic, or sometimes both together; they ought first to be exposed to the fire by themselves in order not only to determine with which of them they are mineralised, but also to set them free from these volatile mineralising bodies: And this also serves instead of calcination, by which they are prepared for further essays.
Here it must be observed, that, whenever any metal or fusible ore is to be tried, a little concavity must be made in that place of the charcoal where the matter is to be put; because, as soon as it is melted, it forms itself into a globular figure, and might then roll from the charcoal, if its surface was plain; but when borax is put to it, this inconvenience is not so much to be feared.
Whenever an ore is to be tried, a small bit is broke off for that purpose, of such a size as has been directed; this bit is laid upon the charcoal, and the flame blown on it slowly. Then the sulphur or arsenic begins to part from it in form of smoke; these are easily distinguished from one another by their smell, that of sulphur being sufficiently known, and the arsenic smelling like garlic. The flame ought to be blown very softly, as long as any smoke is seen to arise from the ore; but after that the heat must be augmented by degrees, in order to make the calcination as perfect as possible. If the heat is applied very strong from the beginning upon an ore that contains much of the sulphur or arsenic, this ore will presently melt, and yet lose very little of its mineralising bodies, and by that means render the calcination very imperfect. It is, however, impossible to calcine the ores in this manner to the utmost perfection, which is easily seen in the following instance, viz. in melting down a calcined potter's ore with borax, it will be found to bubble upon the coal, which depends on the fulphur Apparatus.
Of experiments. Of experiments.
Mineralogy.
Of experiments.
Tulphur which is still left, the vitriolic acid of this uniting with the borax, and causing this motion. However, lead, in its metallic form, melted in this manner, bubbles alone upon the charcoal, if any sulphur remains in it. But as the lead, as well as some of the other metals, may raise bubbles upon the charcoal, although they are quite free from the sulphur, only by the flame's being forced too violently on it, these phenomena ought not to be confounded with each other.
The ores being thus calcined, the metals contained in them may be discovered, either by being melted alone, or with fluxes: when they show themselves either in their pure metallic state, or by tingling the flag with colours peculiar to each of them. In these experiments, it is not to be expected that the quantity of metal contained in the ore should be exactly determined; this must be done in larger laboratories. This cannot, however, be looked upon as any defect, since it is sufficient for a mineralogist only to find out what sort of metal is contained in the ore. There is another circumstance which is a more real defect in our little laboratory, which is, that some ores are not at all able to be tried in it by so small an apparatus: for instance, the gold ore called pyrites aureus, which consists of gold, iron, and sulphur. The greatest quantity of gold which this ore contains is about one ounce, or one ounce and an half; out of 100 pounds of the ore, the rest being iron and sulphur; and as only a very small bit is allowed for these experiments, the gold contained therein can hardly be discerned by the eye, even if it could be extracted; but it goes along with the iron in the flag, this last metal being in so large a quantity in proportion to the other, and both of them being capable of mixture with each other.
All the kinds of blende, black-jack, which are mineralised zinc ores, containing zinc, sulphur, and iron, cannot be tried this way, because they cannot be perfectly calcined; and besides, the zinc flies off, when the iron scorifies: neither can all those blends which contain silver or gold mineralised with them, be tried in this manner, which is particularly owing to the imperfect calcination: nor are the quicksilver ores fit for these experiments; the volatility of this semi-metal making it impossible to bring it out of the poorer sort of ores; and the rich ores which sweat out the quicksilver, when kept close in the hand, not wanting any of these effluvia, &c. Those ores ought to be assayed in larger quantities, and by methods which cannot be applied upon a piece of charcoal.
Some of the rich silver ores are easily tried: for instance, minera argentii vitrea, commonly called silver glass, which consists only of silver and sulphur. When this ore is exposed to the flame, it melts instantly, and the sulphur goes away in fume, leaving the silver pure upon the charcoal, in a globular form. If this silver should happen to be of a dirty appearance, which often is the case, then it must be melted anew with a very little borax; and after it has been kept in fusion for a minute or two, so as to be perfectly melted and red-hot, the proof is suffered to cool: it may then be taken off the coal, and being laid upon the steel-plate, the silver is separated from the flag by one or two strokes of the hammer. Here the use of the iron ring is manifest; for this ought first to be placed upon the plate, to hinder the proof from flying off by the violence of the stroke, which otherwise would happen. The silver is then found inclosed in the flag of a globular form, and quite shining, as if it were polished. When a large quantity of silver is contained in a lead ore, viz. in a potter's ore, it can likewise be discovered through the use of the blowpipe.
Of pure tin ores, the tin may be melted out in its metallic state. Some of these ores melt very easily, and yield their metal in quantity, if only exposed to the fire by themselves: but others are more refractory; and as these melt very slowly, the tin, which sweats out in form of very small globules, is instantly burnt to ashes, before these globules have time to unite in order to compose a larger globe which might be seen by the eye, and is not so soon destroyed by the fire; it is therefore necessary to add a little borax to these from the beginning, and then to blow the flame violently at the proof. The borax does here preserve the metal from being too soon calcined; and even contributes to the readier collecting of the small metallic particles, which soon are seen to form themselves into a globule of metallic tin at the bottom of the whole mass, nearest to the charcoal. As soon as so much of metallic tin is produced as is sufficient to convince the operator of its presence, the fire ought to cease, although not the whole of the ore be yet melted; because seldom, or rather never, the whole of this kind of ore can be reduced into metal by means of these experiments, a great deal thereof always being calcined: and if the fire is continued too long, perhaps even the metal, already reduced, may likewise be burnt to ashes; for the tin is very soon calcined by the fire.
Most part of the lead ores may be brought to a metallic lead upon the charcoal. The minera plumbi calciformes, which are pure, are easily melted into lead: but such of them as are mixed with an ochra-ferris, or any kind of earth, as clay, lime, &c. yield very little of lead, and even nothing at all, if the heterogeneous are combined therewith in any large quantity: this happens even with the minera plumbi calciformis arsenica mixta. These, therefore, are not to be tried but in larger laboratories. However, every mineral body suspected to contain any metallic substance, may be tried by the blow-pipe, so as to give sufficient proofs whether it contains or not, by its effects being different from those of the stone or earths, &c.
The minera plumbi mineralisate leave the lead in a metallic form, if too large a quantity of iron be not mixed with it. For example, when a tessellated or steel-grained lead-ore is exposed to the flames, its sulphur, and even the arsenic, if there be any, begins to fume, and the ore itself immediately to melt into a globular form; the rest of the sulphur continues then to fly off, if the flame is blown slowly upon the mass; instead of that, very little of the sulphur will go off, if the flame is forced violently on it: in this case, it rather happens that the lead itself crackles and dissipates, throwing about very minute metallic particles. The sulphur being driven out as much as possible, which is known by finding no sulphurous vapour in smelling at the proof, the whole is suffered to cool, and then a globule of metallic lead will be left upon the coal. If any iron is contained in the lead ore, the lead which is melted out of it is not of a metallic shining, but rather of a black and uneven surface: a little borax must in this case be melted with it, and as soon as no bubble is seen to rise any longer from the metal into the borax, the fire must be discontinued; when the mass is grown cold, the iron will be found scorified with the borax, and the lead left pure and of a shining colour.
The borax does not scorify the lead in these small experiments, when it is pure: if the flame is forced with violence on it, a bubbling will ensue, resembling that which is observed when borax dissolves a body melted with it; but when the fire ceases, the flag will be perfectly clear and transparent, and a quantity of very minute lead particles will be seen spread about in the borax, which have been torn off from the mass during the bubbling.
If such a lead ore is rich in silver, this last metal may likewise be discovered by this experiment; because, as the lead is volatile, it may be forced off, and the silver remain. To effect this, the lead, which is melted out of the ore, must be kept in constant fusion with a slow heat, that it may be consumed. This end will be sooner obtained, and the lead part quicker, if, during the fusion, the wind through the blow-pipe be directed immediately, though not forcibly, upon the melted mass itself, until it begins to cool, then the fire must be directed on it again. The lead, which is already in a volatilising state, will by this artifice be driven out in form of a subtile smoke; and by thus continuing by turns to melt the mass, and then to blow off the lead, as has been said, until no smoke is any longer perceived, the silver will at last be obtained pure. The same observation holds good here also which was made about the gold, that, as none but very little bits of the ores can be employed in these experiments, it will be difficult to extract the silver out of a pure ore; for some part of it will fly off with the lead, and what might be left is too little to be discerned by the eye. The silver which by this means is obtained is easily distinguished from lead by the following external marks, viz. that it must be red-hot before it can be melted: it cools sooner than lead: it has a silver colour; that is to say, brighter and whiter than lead: and is harder to beat with the hammer.
The minera cupri calciformes, (at least some of them) when mixed with too much stone or earth, are easily reduced to copper with any flux: if the copper is found not to have its natural bright colour, it must be melted with a little borax, which purifies it. Some of these ores do not at all discover their metal, if not immediately melted with borax; the heterogeneity contained in them hindering the fusion, before these are scorified by the flux.
The grey copper ores, which only consist of copper and sulphur, are tried almost in the same manner as the preceding. Being exposed to the flame by themselves, they will be found instantly to melt, and part of their sulphur to go off. The copper may afterwards be obtained in two ways: the one, by keeping the proof in fusion for about a minute, and then exposing it to cool; when it will be found to have a dark and uneven appearance externally, but which, after being broken, discovers the metallic copper of a globular form in its centre, surrounded with a crust, which still contains some sulphur and a portion of the metal: the other, by being melted with borax, which last way sometimes makes the metal appear sooner.
The minera cupri pyritacea, containing copper, sulphur, and iron, may be tried with the blow-pipe, if they are not too poor: in these experiments the ore ought to be calcined, and after that the iron scorified. For this purpose a bit of the ore must be exposed to a slow flame, that as much of the sulphur as possible may part from it before it is melted; because the ore commonly melts very soon, and then the sulphur is more difficult to drive off. After being melted, it must be kept in fusion with a strong fire, for about a minute, that a great part of the iron may be calcined: and, after that, some borax must be added, which scorifies the iron, and turns with it to a black flag. If the ore is very rich, a metallic copper will be had in the flag, after the scorification: if the ore is of a moderate richness, the copper will still retain a little sulphur, and sometimes iron: the product will therefore be brittle, and must with great caution be separated from the flag, that it may not break into pieces; and if this product is afterwards treated in the same manner as before said, in speaking of the grey copper ores, the metal will soon be produced. But, if the ore is poor, the product after the first scorification must be brought into fusion, and afterwards melted with some fresh borax, in order to calcine and scorify the remaining portion of iron; after which it may be treated as mentioned no. 47. The copper will, in this last case, be found in a very small globule.
The copper is not very easily scorified with this apparatus, when it is melted together with borax; unless it has first been exposed to the fire by itself for a while, in order to be calcined. When only a little of this metal is dissolved, it instantly tinges the flag of a reddish-brown colour, and mostly opaque; but as soon as this flag is kept in fusion for a little while, it becomes quite green and transparent: and thus the presence of the copper may be discovered by the colour, when it is concealed in heterogeneous bodies, so as not to be discovered by any other experiment.
If metallic copper is melted with borax by a slow fire, and only for a very little time, the glass, or flag, becomes of a fine transparent blue or violet colour, inclining more or less to the green: but this colour is not properly owing to the copper, but it may rather be to its phlogiston; because the same colour is to be had in the same manner from iron: and these glasses which are coloured with either of these two metals, soon lose their colour if exposed to a strong fire, in which they are made quite clear and colourless. Besides, if this glass, tinged blue with the copper, is again melted with more of this metal, it becomes of a good green colour, which for a long time keeps unchanged in the fire.
The iron ores, when pure, can never be melted by themselves, through the means of the blow-pipe alone; nor Apparatus.
Of Experiments.
nor do they yield their metal, when melted with fluxes, because they require too strong a heat to be brought into fusion; and, as both the ore and the metal itself very soon lose their phlogiston in the fire, and cannot be supplied with a sufficient quantity from the charcoal, so likewise they are very soon calcined in the fire. This easy calcination is also the reason why the fluxes, for instance borax, readily scoriify this ore, and even the metal itself. The iron loses its phlogiston in the fire sooner than the copper, it is therefore easier scoriified; and this is the principle on which the experiment mentioned n° 48. is founded.
The iron is, however, discovered without much difficulty, although it be mixed but in a very small quantity with heterogeneous bodies. The ore, or those bodies which contain any large quantity of the metal, are all attracted by the loadstone, some without any previous calcination, and others not till after having been roasted. When a clay is mixed with a little iron, it commonly melts by itself in the fire; but, if this metal is contained in a limestone, it does not promote the fusion, but gives the stone a dark, and sometimes a deep black colour, which always is the character of iron. A minera ferri calciformis pura crystallifata, is commonly of a red colour; this being exposed to the flame, becomes quite black; and is then readily attracted by the loadstone, which it was not before. Besides these signs, the iron discovers itself, by tinging the flag of a green transparent colour, inclining to brown, when only a little of the metal is scoriified; but as soon as any large quantity thereof is dissolved in the flag, this becomes first a blackish brown, and afterwards quite black and opaque.
Bismuth is known by its communicating a yellowish-brown colour to borax; and arsenic by its volatility, and garlick smell. Antimony, both in form of regulus and ore, is wholly volatile in the fire, when it is not mixed with any other metal (except arsenic), and is known by its particular smell; easier to be distinguished, when once known, than described. When the ore of antimony is melted upon the charcoal, it bubbles constantly during its volatilising.
Zinc ores are not easily tried upon the coal (n° 39.) But the regulus of zinc, exposed to the fire upon the charcoal, burns with a beautiful blue flame, and forms itself almost instantly into white flowers, which are the common flowers of zinc.
Cobalt is particularly remarkable for giving to the glass a blue colour, which is the zaffre or smalt. To produce this, a piece of cobalt ore must be calcined in the fire (36, 37.) and afterwards melted with borax. As soon as the glass, during the fusion, from being clear, seems to grow opaque it is a sign that it is already tinged a little; the fire is then to be discontinued, and the operator must take hold, with the nippers, of a little of the glass whilst yet hot, and draw it out slowly in the beginning, but afterwards very quick, before it cools, whereby a thread of the coloured glass is procured, more or less thick, on which the colour may easier be seen against the day or candle light than if it were left in a globular form. The thread melts easily if only put in the flame of the candle, without the help of the blow-pipe.
If this glass is melted again with more of the cobalt, and kept in fusion for a while, the colour becomes very deep; and thus the colour may be altered, according to pleasure.
When the cobalt ore is pure, or at least contains but little iron, a cobalt regulus is almost instantly produced in the borax, during the fusion; but when it is mixed with a quantity of iron, this last metal ought first to be separated, which is easily performed, since it scoriifies sooner than the cobalt; therefore, as long as the flag retains any brown or black colour (55.) it must be separated, and melted again with fresh borax, until it shew the colour.
Nickel is very seldom to be had, as its ores are seldom free from mixtures of other metals. It is very difficultly tried with the blow-pipe. However, when this semi-metal is mixed with iron and cobalt, it is easily freed from these heterogeneous metals, and reduced to a pure nickel regulus, by means of scoriification with borax, in the same manner as is mentioned (46.), because both the iron and cobalt sooner scoriify than the nickel. The regulus of nickel itself is of a green colour, when calcined: it requires a pretty strong fire before it melts, and tinges the borax with a jacinth colour. Manganese gives the same colour to borax; but its other qualities are quite different, so as not to be confounded with the nickel.
Thus we have briefly described the use of the blow-pipe, and the method of employing it in the study of mineralogy. Any gentleman who is a lover of this science, will, by attending to the rules here laid down, be able in an easy manner to amuse himself in discovering the properties of those works of nature which the mineral kingdom furnishes us with. The husbandman may by its help find out what sorts of stones earths, ores, &c. there are on his estate, and to what economical uses they may be employed. The scientific mineralist may, by examining into the properties and effects of the mineral bodies, discover the natural relation these bodies stand in to each other, and thereby furnish himself with materials for establishing a mineral system, founded on such principles as nature herself has laid down in them; and this in his own study, without being forced to have recourse to large laboratories, crucibles, furnaces, &c. which is attended with a great deal of trouble, and is the reason why so few can have an opportunity of gratifying their desire of knowledge in this part of natural history. It is to be hoped, that the more general its use becomes, the more and sooner will its imperfections be removed, and such additions made as may be found necessary and convenient. We shall now add some hints towards these improvements, leaving to the judicious practitioner the manner of completing them.
A greater number of fluxes might perhaps be found out, whose effects on mineral bodies might be different from those already in use, whereby more distinct characters of those mineral bodies might be discovered, which now either shew ambiguous ones, or which are almost impossible to be exactly tried by the blow-pipe. Instead of the sal soda, some other salts might be found out, more fit for these experiments. But it is very necessary not to make use of any other fluxes than such as have no attraction to the charcoal: if they at the same time are clear and transparent when melted, as the borax and sal fusibile microcosmicum, it is still better: Of Experiment: however, the transparency or opacity are of no great consequence, if a substance is effayed only in order to discover its fusibility, without any attention to its colour; in which case, some metallic flag perhaps might be useful.
When such ores are to be reduced whose metals are very apt to calcine, such as tin, zinc, &c. it might perhaps be of service to add some phlogiston, since the charcoal cannot afford enough of it in the open fire of these effays: such a phlogiston might be the hard resin, or some such body. The manner of melting the volatile metals out of their ores per descensum might also perhaps be imitated: for instance, a hole might be made in the charcoal, wide above, and very narrow at the bottom; a little piece of ore being then laid at the upper end of the hole, and covered with some very small pieces of the charcoal, the flame must be directed on the top: the metal might, perhaps, by this method gather in the hole below, removed from the violence of the fire, particularly if the ore is very fusible, &c.
The use of the pocket laboratory, as here described, is chiefly calculated for a travelling mineralist. But a person who is always residing at one and the same place, may by some small alteration make it more commodious to himself, and avoid the trouble of blowing with the mouth. For this purpose he may have the blow-pipe go through a hole in a table, and fixed underneath to a small pair of bellows with double bottoms, such as some of the glass-blowers use, and then nothing more is required than to move the bellows with the feet during the experiment; but in this case a lamp may be used instead of a candle. This method would be attended with a still greater advantage, if there were many such parts as fig. 2. No. 2. (Plate IV. Vol. II.) the openings of which were of different dimensions: these parts might by means of a screw be fastened to the main body of the blow-pipe, and taken away at pleasure. The benefit of having these nozzles of different capacities at their ends, would be that of exciting a stronger or weaker heat as occasion might require. It would only be necessary to observe, that in proportion as the opening of the pipe (nozzle) is enlarged, the quantity of the flame must be augmented by a thicker wick in the lamp, and the force of blowing increased by means of weights laid on the bellows. A much more intense heat would thus be procured by a pipe of a considerable opening at the end, by which the experiments might undoubtedly be carried farther than with the common blow-pipe.
A traveller, who has seldom an opportunity of carrying many things along with him, may very well be contented with this pocket laboratory, and its apparatus, which is sufficient for most part of such experiments as can be made on a journey. There are, however, other things very useful to have at hand on a journey, which ought to make a second part of the pocket-laboratory, if the manner of travelling does not oppose it: this consists of a little box including the different acids, and one or two matrasses, in order to try the mineral bodies in liquid menstrua, if required.
These acids are, the acid of nitre, of vitriol, and of common salt. Most of the stones and earths are attacked, at least in some degree, by the acids; but the calcareous are the easiest of all to be dissolved by them, which is accounted for by their calcareous properties.
The acid of nitre is that which is most used in these experiments; it dissolves the limestone, when pure, perfectly, with a violent effervescence, and the solution becomes clear: when the limestone enters into some other body, it is nevertheless discovered by this acid, through a greater or lesser effervescence in proportion to the quantity of the calcareous particles, unless there are so few as to be almost concealed from the acid by the heterogeneous ones. In this manner, a calcareous body, which sometimes nearly resembles a siliceous or argillaceous one, may be known from these latter, without the help of the blow-pipe, only by pouring one or two drops of this acid upon the subject, which is very convenient when there is no opportunity nor time for using this instrument.
The gypsum, which consist of lime and the vitriolic acid, are not in the least attacked by the acid of nitre, if they contain a sufficient quantity of their own acid, because the vitriolic acid has a stronger attraction to the lime than the acid of nitre: but if the calcareous substance is not perfectly saturated with the acid of vitriol, then an effervescence arises with the acid of nitre, more or less in proportion to the want of the vitriolic acid. These circumstances are often very essential in distinguishing the calcarei and gypsum from one another.
The acid of nitre is likewise necessary in trying the zeolites, of which some species have the singular effect to dissolve with effervescence in the abovementioned acid; and within a quarter of an hour, or even sometimes not until several hours after, to change the whole solution into a clear jelly, of so firm a consistence, that the glass, wherein it is contained, may be reversed, without its falling out.
If any mineral body is tried in this menstruum, and only a small quantity is suspected to be dissolved, tho' it was impossible to distinguish it with the eye during the solution, it can easily be discovered by adding to it ad saturitatem a clear solution of an alkali, when the dissolved part will be precipitated, and fall to the bottom. For this purpose the sal soda may be very useful.
The acid of nitre will suffice for making experiments upon stones and earths; but if the experiments are to be extended to the metals, the other two acids are also necessary. As the acids are very corrosive, they must not be kept in the ordinary pocket-laboratory, already described, for fear of spoiling the other apparatus, if the stoppers should happen not to fit exactly to the necks of the bottles, and some of the acid should be spilt.
For these acids a separate box must be made, which is eight inches and three quarters long, four inches broad, and five inches high (a). In this box are three long and narrow bottles, containing the acids, placed upright at one end of it, two glass matrasses laid horizontally in the upper part, and a little drawer underneath, made on purpose to fill the empty room below the matrasses, and to give the box a regular form; and as charcoal is not everywhere to be met with in travelling, a piece ought always to be kept in this drawer for the use of the blow-pipe.
(a) But these dimensions, originally directed, have been since reduced, as mentioned under no. 3. par. results. In order to keep the acids more close in the bottles, since the glass-stopper is not always sufficient, there is a glass-cover besides, made so as to screw round the neck of the bottle; and if this is nicely made, nothing can come through, though the box be inclined, or even reversed, which sometimes may happen. The form of the glass matrasses is seen fig. 4. They ought to be very thin at the bottom, that they may not crack by being suddenly put over the fire or taken off it. In these matrasses solutions may very easily be made over the flame of a candle: every mineral body capable of being affected by the acids in this degree of heat, may here be dissolved, and particularly the metals.
Another instrument is likewise necessary to a complete pocket-laboratory, viz. a washing-trough; in which the mineral bodies, and particularly the ores, may be separated from each other, and from the adherent rock, by means of water.
This trough is very common in the laboratories, and is used of different sizes; but here only one is required of a moderate size, such as twelve inches and a half long, three inches broad at the one end, and one inch and a half at the other end (b), sloping down from the sides and the broad end to the bottom, where it is three quarters of an inch deep: we have given a figure of it in fig. 5. It is commonly made of wood, which ought to be chosen smooth, hard, and compact, wherein are no pores in which the minute grains of the pounded matter may conceal themselves.
It is to be observed, that if any matter is to be washed which is suspected to contain some native metal, as silver or gold; a trough should be procured for this purpose, of a very shallow slope, because the minute particles of the native metal have then more power to assemble together at the broad end, separate from the other matter.
The management of this trough, or the manner of washing, consists chiefly in this: that when the matter is mixed with about three or four times its quantity of water in the trough, this is kept very loose between two fingers of the left hand, and some light strokes given on its broad end with the right, that it may move backwards and forwards, by which means the heaviest particles assemble at the broad and upper end, from which the lighter ones are to be separated by inclining the trough and pouring a little water on them. By repeating this process, all such particles as are of the same gravity may be collected together, separate from those of a different gravity, provided they all were before equally pounded; though such as are of a clayish nature, are often very difficult to separate from the rest, which, however, is of no great consequence to a skilful and experienced washer. The washing process is very necessary, as there are often rich ores, and even native metals, found concealed in earths and sand in so minute particles, as not to be discovered by any other means.
Arrangement of Mineral Bodies.
The bodies belonging to the mineral kingdom are divided into four different classes, viz.
1. Earths, or those substances which are not ductile, are mostly indissoluble in water or oil, and preserve their constitution in a strong heat (c).
2. Salts: these dissolve in water, and give it a taste; and when the quantity of water required to keep them in dissolution is evaporated, they concrete again into solid and angular bodies.
3. Inflammable, which can be dissolved in oils, but not in water, and are inflammable.
4. Metals, the heaviest of all bodies; some of which are malleable, and some can be decomposed.
Here, however, it must be observed, that these classes are blended one with another; and therefore some exceptions must be allowed in every one of them: for instance, in the first class, the calcareous earth is in some measure dissoluble in water, and pipeclay with some others diminish somewhat in their bulk when kept for a long time in a calcining heat. In the third class, the calx of arsenic has nearly the same properties as salts; and there is no possible definition of salt, that can exclude the arsenic, though at the same time it is impossible to arrange it elsewhere than among the semi-metals. In the fourth class it is to be observed, that the metals and semi-metals, perfect or imperfect, have not the same qualities common to them all; because some of them may be calcined, or deprived of their phlogiston, in the same degree of fire in which others are not in the least changed, unless particular artifices or processes are made use of: some of them also may be made malleable, while others are by no means to be rendered so. That the convex surface metals take after being melted, is a quality not particularly belonging to them, because every thing that is perfectly fluid in the fire, and has no attraction to the vessel in which it is kept, or to any added matter, takes the same figure; as we find borax, salifiable microcosmicum, and others do, when melted upon a piece of charcoal: therefore, with regard to all that has been said, it is hardly worth while to invent such definitions as shall include several species at once; we ought rather to be content with perfectly knowing them separately.
The First Class.
Earths, are those mineral bodies, not ductile, for the most part not dissoluble in water or oils, and that preserve their constitution in a strong heat.
These earths are here arranged according to their constituent parts, so far as hitherto discovered, and are divided into nine orders.
The First Order.
The Calcareous kinds. These, when pure, and free from heterogeneous matters, have the following qualities common to them all:
1. That they become friable when burnt in the fire, and afterwards fall into a white powder. 2. That their falling into powder is promoted, if, after being burnt, they are thrown into water, whereby a strong heat arises, and a partial solution. 3. They cannot be melted by themselves into glass in the strongest fire. 4. When burnt, they augment the causticity of the lixivium of potashes. 5. They
(b) Reduced dimensions are mentioned under no 3. par ult. (c) By earths, the author (Mr Cronstedt) does not mean (strictly speaking) only earths, but includes all the kinds of stones or fossils not inflammable, saline, or metallic. 5. They are dissolved in acids with effervescence, in the following manner: a. The acid of vitriol partly unites with them, and forms a precipitate, which is a gypseous earth; and partly shoots into selenitical crystals with that which is kept dissolved, after a due evaporation. b. With the acid of common salt they make a sal ammoniacum fixum, which also partly precipitates itself. c. The acid of nitre dissolves them perfectly, and does not part with them again, unless some alkaline salt is added.
6. They melt easily with borax into a glass, which suffers impressions in a degree of heat below ignition.
7. They likewise fuse into a glass with sal fusibile microcofinicum with an effervescence (n).
8. They melt the readiest of all kinds of stones, with the calces, into a corrosive glass or flag.
9. They have also some power of reducing certain metallic earths or calces; for instance, those of lead and of bismuth, and likewise, tho' in a less degree, those of copper and of iron: thus,
10. Do they, in this last-mentioned article (9.), as well as in other circumstances, resemble a fixed alkaline salt; from whence also this whole kind is very often, and properly, called alkaline earths.
The calcareous earth is found,
I. Pure, 1. In form of powder. Agaricus mineralis, or lac lune. a. White, is found in moors, and at the bottom of lakes. b. Red. c. Yellow.—This kind of earth seems to be an impalpable powder of mouldered limestones abraded and collected by the waters, and is therefore common in the neighbourhoods where limestones are found; and tho' the stone be at some distance, which is sometimes the case, still nothing contradictory appears in this opinion of the origin of this species; since in that case it has only been carried farther by the greater rapidity of a stronger current of water. When this earth is found in the crests of rocks, it receives more pompous names; such as gur, lac lune, &c. It burns readily into lime, if it is previously stamped, that it may better cohere: it is then, or in its native state, used for whitewashing, but easily rubs off by the least touch.
At certain places in the province of Smoland in Sweden, there is found in the moors a white earth, which, by its external appearance, resembles the species here described; but it does not show any marks of effervescence with acids, nor does it burn into lime. It were to be wished, that those who have an opportunity of getting any quantity of this latter earth, would undertake to examine it better.
2. Friable and compact. Chalk, creta. a. White, creta alba, is found in England, France, and in the province of Skone in Sweden, in which last place it is only found adherent to flint. In the two first kingdoms there are large strata of this substance, in which flint is imbedded. This seems to indicate, that the loose flints, or those dispersed on the surface of the earth, have been by some causes carried from their native beds; but, as yet, no one can prove, that chalk and flint are of the same constituent parts.—Chalk is, however a vague name, also applied to other earths; whence we hear of chalks of various colours; but there are none which are known to be of a calcareous nature, except this kind here described; and of which there are no other varieties, otherwise than in regard to the looseness of the texture, or the fineness of the particles.
3. Indurated, or hard; Terra calcarea indurata. Limestone; Lapis calcareus.
A. Solid, of no visible particles, or not granulated. This kind varies in regard to hardness and colour; for instance, a. White. b. Whitish yellow. c. Flesh-coloured, found in loose masses. d. Reddish brown. e. Grey. f. Variegated with many colours, and particularly called marble. g. Black.
B. Grained or granulated limestone; Lapis calcareus particulis granulatis.
1. Coarse-grained and of a loose texture, called salt-flag in Swedish, from its resemblance to lumps of salt. a. Reddish yellow. b. White.
The grained flux spar is also sometimes called salt-flag.
2. Fine-grained. a. White. b. Semi-transparent, from Solfatara in Italy, in which native brimstone is found.
3. Very fine grained. a. White and green. b. White and black.—This species has often as beautiful colours as those commonly called marbles; but the texture and coherency of its particles will not admit of a good polish.
C. Scaly limestone; Lapis calcareus particulis squamosis, five spatulis.
1. With coarse or large scales. a. White.
Some kinds of this lose in a calcining heat 40 per cent. of their weight; and, exposed to the air, get a brownish efflorescence, a sign that they contain some iron, and are a medium between a limestone and the white iron ore called stahlsteine; nor do they excite any effervescence with acids in their crude state.
b. Reddish yellow.
2. With small scales. a. White.
3. Fine glittering or sparkling. a. White.
(n) This effervescence is also made with the borax, as well as with this sal fusibile microcofinicum; and it is also to be observed, that the glasses made with these salts are quite colourless and transparent. Order I.
**MINERALOGY.**
1. **Dog's teeth; Pyramidales distincti.** Found at Salberg, and in the iron mines at Dannemora in the province of Upland.
2. **Balls of crystallized spar, Pyramidales concreti.** These are balls which have drusen, pyramidal, octaedral, spars accreted in their hollows or centres: they are found at Rettvin in the province of Dalarne, and other places (f).
F. **Stalactitical spar; Stalactites calcareus.** Stalactites, Stone-icicle, or Drop-stone. This is formed from water saturated with lime, which, while running or dropping, deposits by degrees the calcareous earth which it has carried along with it from clefts of rocks, or from out of the earth. It is therefore commonly of a fleshy, though sometimes of a solid and sparry texture. Its external figure depends on the place where it is formed, or the quantity of the matter contained in the water, and other like circumstances.
(1.) Scaled stalactites of very fine particles.
a. Of a globular form.
1. White, the pea-stone.
2. Grey, pisolithus, oolithus. Also the hammites, from its resemblance to the roes or spawn of fish. It has been exhibited by authors as petrified roes. The Keton free-stone, of Rutlandshire, is a remarkable stone of this sort.
b. Hollow, in the form of a cone.
1. White, is found everywhere in vaults made with mortar, and through which water has had an opportunity to penetrate; and also in grottos dug in rocks of limestone.
c. Of an indeterminate figure. Sinter.
d. Of coherent hollow cones. Of this kind is a stalactitical crust, which has formed a stratum, or rather filled a fissure between the strata of the earth, at Helsingborg in the province of Skone; it is of a very singular figure, resembling conical caps of paper placed and fixed one in the other, diminishing by degrees both in height and the other dimensions.
2. Solid.
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(e) The translator of Mr Cronstedt's treatise has adopted this German term drusen into the English language, for a cluster of regular-figured bodies, as a group conveys the idea of a cluster only, whether regular or of indeterminate figures.
(f) The name spar is very well known, and only used to determine a certain figure, viz., when a stone breaks into a rhomboidal, cubical, or a plated form, with smooth and polished surfaces, it is called spar: and as it is thus applied to stones of different kinds, without any regard to their principles, one ought necessarily to add some term to express the constituent parts at the same time that the figure is mentioned; for instance, calcareous spar, gypseous spar, flux spar, flint or cockle spar, &c. This term, however, is applied only to earths, and such ores as are of the same figure as the lead spar, &c.
All crystallized spars, when broken, show the sparry figure in their particles, and the crystallization is to be ascribed to the empty space left by the contraction of the sparry principle; such holes filled with drusen of spars, are in Swedish called drake, or druse-hol.
The figure of the crystals varies more in this genus than in any other, for which no reason can be assigned; it ought not to be ascribed to salts, as long as the presence of any such cannot be proved: but there are strong indications to suspect, that other substances may likewise have received the same property to assume an angular surface on certain occasions. See Mr Cronstedt's Introductory Speech at the Royal Academy of Sciences at Stockholm.
Besides, the consideration of those figures is a thing of more curiosity than of real use, because no miner has yet been able to make any conclusion relative to the quantity or quality of the ores, from the difference of the figures of spars found along with them; and the grotto-makers never take any notice of the angles or sides, but think it sufficient for their purpose if they make a fine or glittering appearance at a distance.
It would, nevertheless, be well if any one would take upon himself the trouble to observe whether each species of spar has not a certain determinate number of figures or sides, within which it is confined, in its accretions. This it has hitherto been impossible to do, because all species of spars have been confounded together, without regard to their different principles. (2.) Solid stalactites of a sparry texture.
a. Hollow, and in form of a cone.
1. White, and semitransparent.
In making lime-water, one may observe how the lime gathers first like a pellicle on the surface of the water, and afterwards, when this breaks, falls down to the bottom in form of a scaly sediment, which is called cremer calcis: after that a new pellicle is formed, which likewise falls down; and in this manner it continues for a long while, although the lime-water had before been passed through a filter. This we may also imagine to be the way in which the works of nature are performed: whence the stalactites commonly is of a scaly texture, or at least discovers some tendency towards it. But a stalactite of a sparry texture, such as above-mentioned from Rouen, may be supposed to be owing to a more copious principle concurring at once: and in the same manner the sparry limestone and its crystallisations seem likewise to have been produced; since they, as far as we know, are only found in clefts, which, when they have been filled up with a stony matter, the Swedish miners call klyster, and gangar, or veins. In regard to this, the stalactites, the sparry limestone, and also its crystallisations, might all be ranked under the same title in a systematical description, as very little different from one another, if it were not necessary, in describing mines and other works, to give them their separate names; because it is certain, that a piece which is broken from large spar-crystals, or from sparry stalactites, may in a cabinet pass extremely well for a common sparry limestone, without leaving any suspicion of its former figure before it was broke.
II. Satiated or united with the acid of vitriol. Gypsum, Plaster-stone, or Parget.
This is,
1. Looser and more friable than a pure calcareous earth.
2. Either crude or burnt, it does not excite any effervescence with acids; or, at most, it effervesces but in a very slight degree, and then only in proportion as it wants some of the vitriolic acid to complete the saturation.
3. It readily falls into a powder in the fire.
4. If burnt, without being red-hot, its powder readily concretes with water into a mass, which soon hardens; and then,
5. No heat is perceived in the operation.
6. It is nearly as difficult to be melted by itself as the limestone, and shews mostly the same effects with other bodies as the lime-stone: the acid of vitriol seems, however, to promote its vitrification.
7. When melted in the fire with borax, it puffs and bubbles very much, and for a long while, during the fusion, owing to the nature of both the salts.
8. When a small quantity of any gypsum is melted together with borax, the glass becomes colourless and transparent; but some sorts of alabaster and sparry gyps, when melted in some quantity with borax, yield a fine yellow transparent colour, resembling that of the best topazes. This phenomenon might probably happen with every one of the gypseous kind. But it is to be observed, that if too much of such gypsum is used in proportion to the borax, the glass becomes opaque, just as it happens with the pure limestone.
9. Burnt with a phlogiston, it smells of sulphur, and may as well by that means, as by both the alkaline salts, be decomposed; but for this purpose there ought to be five or six times as much weight of salt as of gypsum.
10. Being thus decomposed, the calx or earth which is left shows commonly some marks of iron.
The gypseous earth is found,
(1.) Loose and friable; Terra gypsea pulverulenta. Gypseous earth, properly so called; Guhr.
a. White.
(2.) Indurated,
A. Solid, or of no visible particles, Alabaster.
This stone is very easy to saw and cut, and takes a dull polish. It is not always found saturated with the acid of vitriol.
a. White, alabaster.
1. Clear and transparent.
2. Opaque.
b. Yellow.
1. Transparent, from the Eastern countries.
2. Opaque.
B. Gypsum of a scaled or granulated structure.
This is the common plaster-stone.
1. With coarse scales.
a. White.
2. With small scales. a. Yellowish. b. Greyish.
C. Fibrous gypsum, or plaster-stone, improperly (though commonly) called English tate by our druggists.
1. With the fibres coarse.
a. White, from Livonia.
2. With fine fibres.
a. White.
D. Spar-like gypsum. Selenites. This by some is also called glacies mariae; and is confounded with the clear and transparent mica.
1. Pure selenites.
a. Transparent.
a. Colourless.
b. Yellowish.
2. Spar-like gypsum; Marmor metallicum.
This stone, on account of its heaviness, which comes near to that of tin or iron, is suspected to contain something metallic; but, as far as is hitherto known, no one has yet been able to extract any metal from it, except some traces of iron, which is no more than what all other gyps contain.
a. Semitransparent; spatum Bononiense, the Bononian stone, or phosphorus. Its specific gravity is 4:5000 : 1000.
b. Opaque.
a. White.
3. Liverstone, so called by the Swedes and Germans.
E. Chry- Order I.
E. Crystallised gypsum. Gypseous drusen; drusen efflorescent.
1. Drusen of crystals of pure sparry gypsum. a. Wedge-formed, are composed of a pure spar-like gypsum. 1. Clear and colourless. 2. Whitish yellow. b. Capillary. a. Opaque, whitish yellow. c. Of ponderous spar-like gypsum; Marmor metallicum drusenum. 1. Jagged or like cocks combs, cribrati. These resemble cocks combs, and are found in clefts or fissures accreted on the surfaces of balls of the same substance. 2. White. 3. Reddish.
F. Stalactitical gypsum. Gips finter.
This perhaps may be found of as many different figures as the calcareous stalactites, or fingers.
Mr Cronstedt has only seen the following, viz.
1. Of no visible particles; in French, grignard. a. Of an irregular figure. a. Yellow. b. White. This is used in several works as alabaster, especially when it is found in large pieces; and then it commonly varies in colour between white and yellow, as also in transparency and opacity.
2. Of a spar-like texture. a. In form of a cone. a. White and yellow. b. Of an irregular figure. a. White.
Gypseous fossils abound in England. Plasterstone, granulated and solid, some so very fine as to be alabaster, that is, take a surface and polish, are plenty in Derbyshire and Nottinghamshire, where are large pits of it, and also in most of the cliffs of the Severn, especially at the Old Passage in Somersetshire. A very fine semipellucid solid alabaster is found in Derbyshire. Fibrous talcs, very fine, are found in the same pits of plasterstone above-mentioned, and many other places. Selenites of many kinds abound in England in clays, inasmuch that it is needless to enumerate the places. Very fine gypseous drusen are found in Sheepy-isle; and some, perfectly pellucid as crystal, and large, have been dug from the salt-rocks at Nantwich in Cheshire. The selenites rhomboidalis, a rare fossil in other countries, is frequently found in England; but Shotover-hill, in Oxfordshire, is famous for it. The isle of Sheepy affords a kind peculiar to that small spot of ground, and not found anywhere else in the world, fibrous, and always accreting in radiations like a star on the septaria, thence called stella septarii.
III. Calcareous earth satiated with the acid of common salt. Sal ammoniacum fixum naturale.
This is found, 1. In sea-water. 2. In salt-pits.
It is formed in great quantities at the bottoms of the salt-pans of the salt-works. It attracts the moisture of the air.
IV. Calcareous earth united with the inflammable substance.
These have a very offensive smell, at least when they are rubbed, and receive their colour from the phlogiston, being dark or black in proportion as it predominates.
1. Calcareous earth mixed with phlogiston alone; Lapis fulvus, fetid stone and spar, or twine-stone and spar. Perhaps the smell of this stone may not be so disagreeable to every one: it goes soon off in the fire. Its varieties, in regard to the texture, are as follow: A. Solid, or of no visible or distinct particles. a. Black. B. Grained. a. Blackish brown. C. Scaly, particulis micaces. 1. With coarse scales. a. Black. 2. With fine glittering or sparkling scales. a. Brown. D. Sparry. a. Black. b. Light brown. c. Whitish yellow. E. Crystallised. 1. In a globular form.
2. Calcareous earth united with phlogiston and the vitriolic acid. Leberstein of the Germans and Swedes. Lapis hepaticus.
This stone sometimes readily, at other times only when rubbed, smells like the hepar sulphuris, or gun-powder. It excites no effervescence with acids, and is a medium between the gypsum and the fetid stones (93), to which it has, however, generally been referred, although no lime can be made from it; whereas they are the fittest of all the different limestones to be burnt into lime. It is found,
A. Scaly. 1. With coarse scales. a. Whitish yellow. 2. With fine glittering or sparkling scales. a. Black.
The method that nature takes in combining those matters which compose the liver-stone, may perhaps be the same as when a limestone is laid in a heap of mundane while it is roasting; because there the sulphur unites itself with the limestone, whereby the limestone acquires that smell common to liver of sulphur, instead of which the vitriolic acid alone enters into the formation of gypsum. How the sulphur combines itself may likewise be observed in the slate-balls or kernels from Andrarum alum-mines, where it sometimes combines itself with a martial earth, with which this slate abounds, and forms therewith pyrites within the very slate-balls. The fetid or twine stones, and the liver-stone, are, in regard to the structure of their parts, subject to the same varieties as the other species of limestone; and it is to be observed, that a volatile alkali is commonly supposed to have entered into the composition of the fetid stones, though it has never yet been discovered by any experiment. V. Calcareous earths blended with an argillaceous earth. Marle, Marga.
1. When crude, it makes an effervescence with acids; but,
2. Not after having been burnt; by which operation it is observed to harden, in proportion as the clay exceeds the calcareous substance.
3. It easily melts by itself into a glaas, and even when it is mixed with the most refractory clay.
4. It is of great use in promoting the growth of vegetables, since the clay tempers the drying quality of the calcareous earth.
5. When burnt in a calcining heat, it readily attracts water; and, exposed to the air, in time it falls into a powder.
The varieties of this kind worthy to be taken notice of, depend on the different quantities of each of their component parts, and on the quality of the clay. We shall specify the following examples.
A. Loose and compact, Marga friabilis. This dissolves in water like common clay.
a. Reddish brown. b. Pale red. This, when burnt, is of a yellowish colour, and used for making earthen-ware in some places.
B. Semi-indurated, Marga indurata aëre fætens. It is nearly as hard as stone when first dug up, but moulders in the open air. It is mostly flaky, and is not uncommon in the slate-rocks of Sweden, where it lies between the thick beds of flaky limestone, and is also found by itself forming very thick strata. It does not dissolve in water, till by a considerable length of time it has mouldered to a powder.
a. Grey. b. Red.
C. Indurated or stone marle.
a. In loose pieces, Marga indurata amorpha; by the Germans called duckstein, or tophstein.
a. White. b. Grey.
It is formed from a sediment which the water carries along with it.
n. In continued strata. Hard flaky marle.
VI. Calcareous earth united with a metallic calx.
Here, as well as in the others, such a mixture or combination is to be understood, as cannot be discovered by the eye alone, without the help of some other means.
The subjects belonging to this division lose the property of raising an effervescence with acids, when they are rich in metal, or contain any vitriolic acid. However, there have been found some that contained 20 or 30 per cent. of metal, and yet have shewn their calcareous nature by the nitrous acid.
There are no more than three metals hitherto known to be united in this manner with the calcareous earth, viz.
(1.) Calcareous earth united with iron. White spar-like iron ore, Minera ferri alba. The flabbein or weisser eisenz of the Germans.
1. This ore, however, is not always white, but commonly gives a white powder when rubbed.
2. It becomes black in the open air, as likewise in a calcining heat.
3. In this last circumstance it loses 30 or 40 per cent. of its weight, which by distillation has been found owing to the water that evaporates; and it is possible that some small quantity of vitriolic acid may, at the same time, evaporate with the water.
4. It is of all the iron ores the most easy to melt, and is very corrosive when melted.
This kind is found,
A. Loose; the mouldered part of the indurated sort.
a. Black, like soot. b. Dark brown, somewhat resembling umbre.
B. Indurated.
1. Solid, of no distinct particles.
a. Red. Looks like red ochre, or the red haematites, but dissolves in the acid of nitre with a great effervescence.
2. Scaly, particulis micaceis.
a. White. b. Blackish grey.
3. Spar-like.
a. Light brown.
4. Drusen.
a. Blackish brown. b. White.
1. Porous. This is often called eisenblute, or floe ferri.
2. Cellular.
(2.) Calcareous earth united with copper.
A. Loose and friable. Mountain blue. Germanicè, Bergblau.
This dissolves in aquafortis with effervescence.
B. Indurated.
1. Pure calcareous earth mixed with calx of copper. Armenian stone, lapis Armenus. Such, according to the description of authors, ought the nature of the stone called lapis Armenus to be, though the druggists substitute in its stead a pale blue lapis lazuli, free from marcasite.
2. Gypseous earth united with calx of copper. Is of a green colour; and might perhaps be called turquoise ore, or malachites; though we do not know if all sorts of turquoise ore are of this nature.
a. Semi-transparent, is found at Ardal in Norway. By chemistry we know, that alkaline salts produce a blue colour with copper, which is changed into green as soon as any acid is added; and from thence the reason is obvious why a green colour may be found among calcareous copper ores, viz. when the vitriolic acid is in the neighbourhood of it.
(3.) Calcareous earth united with the calx of lead.
This is a lead ochre, or a spar-like lead ore, which, in its formation, has been mixed with a calcareous earth, and for that reason effervesces with acids.
A. Loose and friable.
a. White, from Kristersberget at Nya Kopparberget in Westmanland.
B. Indurated.
1. Scaly. Order II.
Siliceous Earths.
a. Yellowish.
Both these varieties contain a considerable quantity of lead, viz. 40 per cent. more or less; and the calcareous earth is as equally and intimately mixed with it, as in the white iron ore. Thus may these be distinguished from other lead-ochres and spar-like lead ores, which are much richer in lead, and never effervescence with acids. These last mentioned also seem to be produced by nature, nearly as the spar-like lead ores, and as the flores saturni are formed in calcining a regulus of lead.
The Second Order.
The Siliceous kind.
This siliceous earth is, of all others, the most difficult to describe and to distinguish perfectly; however, it may be known by the following characters, which are common to all bodies belonging to this order.
1. In its indurated state it is hard, if not in regard to the whole, yet at least in regard to each particle of it, in a degree sufficient to strike fire with steel, and to scratch it, when rubbed against it, though the steel be ever so well tempered.
2. When pure, and free from heterogeneous particles, it does not melt by itself, neither in a reverberatory, nor in a blast furnace.
3. After being burnt, it does not fall to a powder, neither in the open air, nor in water, as the calcareous order does, but becomes only a little looser and more cracked by the fire, unless it has been very slowly and by degrees heated.
4. It excites no effervescence with acids.
5. In the fire it melts easiest of all to a glass with the fixed alkaline salt; and hence it has got the name of vitreous, though this name is properly speaking, less applicable to this order than to a great many other earths.
The mineral bodies that are comprehended in this order, are, indeed, somewhat different from one another. This difference, however, on first sight may be discerned; but, in regard to their effects in the fire, and other chemical experiments, it cannot be esteemed of any great consequence, at least while we are no farther advanced in the art of decompounding these hard bodies, and as long as no one has thought it worth the trouble and expense to use those means which are already discovered for this purpose; namely, the burning-glass or concave mirror; and to continue such experiments which Mr Pott has ingeniously begun as a basis for his Lithogeognosia. For want of this, there is no other way left, than to consider these bodies as simple substances, (how much forever compounded they may be), in the following manner.
I. Diamond. Adamas gemma.
Which,
1. Of all stones, is the hardest. 2. Is commonly clear, or transparent; which quality, however, may, perhaps, only belong to its crystals, but not to the rock itself from which they have their origin. 3. Its specific gravity is nearest 3,500. When brought to Europe in its rough state, it is in form either of round pebbles with shining surfaces, or of crystals of an octohedral form. 4. Colourless, or diaphanous, or the diamond properly so called.
But it also retains this name when it is tinged somewhat red or yellow. Being rubbed, it discovers some electrical qualities, and attracts the mastic.
b. Red; Ruby. Adamas ruber; Rubinus.—Which, by lapidaries and jewellers, is, in regard to the colour, divided into,
1. The ruby of a deep red colour inclining a little to purple. 2. Spinell, of a dark colour. 3. The balas, pale red, inclining to violet. This is supposed to be the mother of the rubies. 4. The rubicell, reddish yellow.
However, all authors do not agree in the characters of these stones.
II. Sapphire. Sapphyrus gemma.
It is transparent, of a blue colour; and is said to be in hardness next to the ruby, or diamond.
Sapphires are said to be found in Allatia, at St Amarin; but accounts of this kind are in general not to be depended upon, as the stones are frequently met with in collections and the druggists shops under the name of sapphires, when they are of a deep blue colour; not to mention that the quartz is always termed a precious stone, whenever it is found clear and of a fine colour. The sapphire is said to lose its blue colour in the fire. Those which are but a little tinged are called white sapphires. The sapphire is seldom found of a very deep blue colour, and free from parallel flaws which run through it.
III. Topaz. Topazius gemma.
This is a precious stone which, when rough and perfect, is sold in a crystallized form. At Schneckenstein in Saxony, these crystals are found of a prismatic octohedral form, with no points, but flat, and with some facets at the top; however, without doubt the oriental topazes have another figure.
Experiments by fire have been made on the Schneckenstein topazes by Mr Pott, as may be seen in his Lithogeognosia.
To this kind may be referred,
a. The pale yellow topaz; which is nearly uncoloured, and is found at Schneckenstein. b. The yellow topaz, from Schneckenstein. c. Deep yellow, or gold-coloured topaz, or oriental topaz. d. Orange-coloured topaz. e. The yellowish green topaz, or chrysolite.
It is of a grass-green colour, and may perhaps belong to some other species, which might be discovered, if it could be obtained rough, or in its matrix, and large enough or in such quantity as is necessary for experiments to be made.
f. The yellowish green and cloudy topaz, the chrysoprase.
This is perhaps the substance which serves as a matrix to the chrysolite: for those which have been seen of this kind are like the clear-veined, called called in Swedish milk-crystal, and quartz, which is of the first degree of crystallisation.
g. Bluish green topaz, or the beryl.
This varies in its colours; and is called, when,
1. Of a sea-green colour, the aqua-marine; 2. When more green, the beryl.
They are found in the stream-works in Saxony and Bohemia, in form of pebbles, or round pieces.
IV. Emerald. Smaragdus gemma.
Its chief colour is green, and is transparent. It is the loftest of precious stones, and when heated it is phosphorescent like the fluors. What in some cabinets is given out for its matrix, and said to come from Egypt, is nothing else than a deep green cockle-spar; of which colour we likewise find cockle, or shell, in the island of Uto near Stockholm, and at Norbery in the province of Westmanland in Sweden.
Mr Maillet informs us, that in former times the best emeralds were found in Egypt.
To the precious stones belong also the jacinths, or hyacinths; which are crystals harder than quartz crystals, transparent, of a fine reddish-yellow colour when in their full lustre, and formed in prisms pointed at both ends: these points are always regular, in regard to the number of the facets, being four on each point; but the facets seldom tally: the sides also which form the main body, or column, are very uncertain in regard both to their number and shape; for they are found of four, five, six, seven, and sometimes of eight, sides: further, the column or prism is in some also so compressed, as almost to resemble the face of a spherical faceted garnet. These crystals lose their colour, become white, and do not melt in the fire; by which qualities chiefly they may be distinguished from garnets, which are likewise sometimes found of a colour not inferior to the true jacinths. The author had not, at the time when he wrote this essay, seen the true jacinths; but says that the reddish yellow garnets from Greenland are sold by the jewellers for jacinths; so are likewise the East Indian garnets of the same colour; and, what is still more, there are some jewellers that do not know the true distinctions between a jacinth and a garnet at all, but buy and sell the garnets for jacinths, when they are of a fine reddish yellow colour; this must in particular be owing to the scarcity of the true jacinth.
Mr Cronstedt says he lately got some jacinths of a quadrangular figure, which did not melt in the fire, but only became colourless.
V. Quartz. Quartzum.
This stone is very common in Europe, and easier to be known than described. It is distinguished from the other kinds of the siliceous order, by the following qualities.
1. That it is most generally cracked throughout, even in the rock itself; whereby, 2. As well as by its nature, it breaks irregularly, and into sharp fragments. 3. That it cannot easily be made red-hot, without cracking still more.
4. It never decays in the air. 5. Melted with pot-ashes, it gives a more solid and fixed glass than any other of the siliceous order. 6. When there has been no interruption in its natural accretion, its substance always crystallises into hexagonal prisms pointed at one or both ends. 7. It occurs in clefs, fissures, and small veins in rocks. It very seldom forms large veins, and still seldomer whole mountains, without being mixed with heterogeneous substances.
The quartz is found,
(1.) Pure.
A. Solid, of no visible particles with a glossy surface. Fat quartz. a. Uncoloured and clear, diaphanum. This has no crystallised form, but is nevertheless as clear as quartz crystals of the best water. b. White, the common fat quartz. c. Blue. d. Violet.
B. Grained. a. White. b. Pale green.
C. Sparry quartz. This is the rarest; and ought not to be confounded with the white felt-spat, being of a smoother appearance, and breaking into larger and more irregular planes. a. Whitish yellow. b. White.
D. Crystallised quartz. Rock crystal. Quartz crystal.
Its figure is already described; and, in regard to the colours, the following varieties occur.
1. Opaque, or semi-transparent. a. White, or of a milk colour. b. Red, or of a carnelian colour. c. Black.
2. Clear. a. Blackish brown, smoky topaz, or rauchtopas of the Germans. b. Yellow; found in Bohemia, and sold instead of topazes. c. Violet; the amethyst. d. Uncoloured; rock-crystal, properly so called. When these coloured crystals are not clear, they are called fluss; for instance, topaz-fluss, amethyst-fluss, &c.
(2.) Impure quartz.
A. Mixed with iron, in form of a black calx. This is of a glossy texture, and contains a great quantity of iron. a. Red.
VI. The flint. Silex pyromachus, Lapis corneus, or hornstein of the Germans.
This is equally common with the quartz, and it is full as difficult to describe it; especially as it forms a kind of intermediate substance between quartz and jasper, both which it nearly resembles, that it is not easy to point out such characters as shall readily distinguish it from them. The best way, perhaps, will be to speak of its properties. properties comparatively; and then we may say, that,
1. It is more uniformly solid, and not so much cracked in the mass as the quartz; and, 2. It is more pellucid than the jasper. 3. It bears being exposed to the air, without decaying, better than the jasper, but not so well as the quartz. 4. It is better for making of glass than the jasper, but is not quite so good as quartz for that purpose.
5. Whenever there has been an opportunity in this matter of its shooting into crystals, quartz crystals are always found in it; just as if the quartz had made one of its constituent parts, and had on certain circumstances been squeezed out of it; this is to be seen in every hollow flint, and its clefts, which are always filled up with quartz.
6. It often shows most evident marks of having been originally in a soft and flimsy state.
The several varieties of this species have obtained distinct names, more with respect to their colours than from any real difference in their substance; but these are still necessary to be retained, as the only names used by jewelers and others, who know how to value them accordingly.
(1.) The opal. *Opalus paderota.*
It is the most beautiful of all the flint kind, owing to the changeable appearance of its colours by reflection and refraction, and must therefore be described under both these circumstances.
a. The opal of Nonius, the sanguineous of the Indians.
This appears olive-coloured by reflection, and seems then to be opaque; but when held against the light, is found transparent, and of a fine ruby red.
That opal is supposed to have been of this kind, which Pliny mentions in his Natural History, chap. 307, sect. 21, and which he says was in the senator Nonius's possession, who rather suffered banishment than part with it to Antony.
This stone was at that time valued in Rome at 20,000 sesterces. But the stone here particularly described, was found in the ruins of Alexandria; it is about the size of a hazel-nut, and was bought for a trifle of a French drug-gift, named Robby, and presented to the French general confidant Lironcourt, who afterwards offered it to sale in several places for the sum of 40,000 rixdollars. See Hasselquist's Travels to the East, under the article of Opal.
This very stone was in the year 1763 in the possession of his excellency the duke de Nivernois, then ambassador to the British court.
There is, however, another of the same kind in Sweden, which by reflection appears rather brown; but by refraction is red, with violet veins.
b. The white opal. Its ground is white, of a glass-like complexion, from whence are thrown out green, yellow, and bluish rays; but it is of a reddish or rather flame colour, when held against the light.
1. Of many colours. The oriental opal. 2. Of a milky colour. 3. Bluish, and semi-transparent. This is not so much valued as those which are more opaque, because it is easier to be imitated by art.
(2.) The cat's eye. *Pseudopalus.*
This stone is opaque, and reflects green and yellowish rays from its surface, and is found in Siberia.
(3.) The onyx. *Onyx camehuja.* Memphites.
This stone is the hardest of the flinty tribe; and consists of differently coloured veins, which run parallel to one another, sometimes in straight, sometimes in curved lines. It is found of two sorts.
a. Nail-coloured onyx, having pale flesh-coloured and white lines. From the river Tomm in Siberia.
b. With black and white lines. The oriental onyx.
The old Romans were accustomed to cut figures in relief on the straight-lined onyxes, which they called camehuja; these are still counterfeited, and called cameyus. Those which consist of concentric circles were called memphite; and we have now of this kind cut to be set in rings, under the name of occhi di gatti, which, however, ought not to be confounded with the pseudopal, or cat's eye.
(4.) The chalcedony, or white agate.
Is a flint of a white colour, like milk diluted with water, more or less opaque; it has veins, circles, and round spots. It is said to be softer than the onyx, but much harder than those agates which are sometimes found of the same colour.
a. The white opaque chalcedony, or cacholong, from the Buchharish Calmucks. This was first made known by one Renez, a Swedish officer, who for several years had been in that country. The inhabitants find this flint on the banks of their rivers, and work idols and domestic vessels out of it.
b. Of white and semi-transparent strata; from Ceylon.
c. Bluish grey; from Ceylon and Siberia.
(5.) The carnelian. *Carniolus.*
Is of a brownish red colour, and often entirely brown. Its name is originally derived from its resemblance to flesh, or to water mixed with blood.
a. Red. b. Yellowish brown, looks like yellow amber, from the river Tomm in Siberia. It is said not to be so hard as the chalcedony.
(6.) The fardonyx.
Is a mixture of the chalcedony and carnelian, sometimes stratum-wise, and sometimes confusedly blended and mixed together.
a. Striped with white and red-strata: this serves as well cut in cameo as the onyx.
b. White, with red dendritical figures. This very much resembles that agate which is called the mocha stone, but with this difference, that the figures are of a red colour in this, instead of black, as in that agate.
Between the onyx, carnelian, chalcedony, fardonyx, and agate, there seems to be no real difference, difference, except some inexplicable degrees of hardness.
(7.) The agate; *Achates*.
This name is given to flints that are variegated with different colours, promiscuously blended together; and they are esteemed in proportion to their mixture of colours, their beauty, and elegance. Hence also they have obtained variety of names, mostly Greek, as if the business of the lapidary in cutting of them, and admiring their several beauties and figures, had been derived from that nation alone.
a. Brown opaque agate, with black veins, and dendritical figures; the Egyptian pebble.
b. Of a chalcedony colour, *achates chalcedonians*.
c. Semi-transparent, with lines of a blackish brown colour, and dendritical figures; the mocha stone. This is much esteemed, and makes a valuable part of some collections, where it has a place chiefly for the sake of its figures, resembling vegetables, animals, &c. which however are often improved by art.
d. Semi-transparent, with red dots; *Gemma divi Stephani*. When the points are very minute, so as to give the stone a red appearance, it is by some called *Sardea*.
e. Semi-transparent, with clouds of an orange colour.
f. Deep red or violet, and semi-transparent.
g. Of many colours, or variegated.
h. Black.
VII. Jasper; *Jaspis*.
All the opaque flints are called by this name, whose texture resembles dry clay, and which have no other known quality, whereby they may be distinguished from other flints, except that they may be more easily melted in the fire; and this quality perhaps may proceed from some heterogeneous mixture, probably of iron.
(1.) Pure jasper; which by no means yet known can be decomposed.
a. Green with red specks or dots; the heliotrope, or blood-stone.
b. Green.
c. Red.
d. Yellow.
e. Red with yellow spots and veins.
f. Black.
(2.) Jaspers containing iron; *Jaspis martialis*, Sinope.
A. Coarse-grained.
a. Red and reddish brown; Sinope.
B. Steel-grained, or fine-grained.
a. Reddish brown: looks like the red ochre or chalk used for drawing; and has partition veins, which are unctuous to the touch, like a fine clay, and other like kinds.
C. Of a solid and shining texture, like a flag.
a. Liver-coloured; and, b. Deep red.
c. Yellow. This last mentioned, when calcined, is attracted by the loadstone; and being essayed, yields 12 to 15 per cent. of iron.
VIII. Rhombic quartz; *Spatum scintillans*, Feltspatum.
This has its name from its figure, but seems to be of the same substance as the jasper. We have not, however, ranked them together, for want of true marks to distinguish the different sorts of the flinty tribe from one another.
This kind is found,
1. Sparry.
a. White.
b. Reddish brown.
c. Pale yellow.
d. Greenish.
This last mentioned resembles very much the schorl or cockle-spar; but is neither so easy to melt in the fire, nor of so exact a figure.
2. Crystallised.
a. In separate or distinct rhomboidal crystals.
The Third Order.
The Garnet kind; *Terrae granatae*.
The matter composing the substance of garnet, and schorl or cockle, except that small portion which is metallic, does in its indurated state resemble the filaceous tribe, so far as relates to external appearance and hardness; and therefore we would willingly have followed the opinion commonly received, of considering these two substances as arising from one another, if we had not been persuaded to the contrary by the following qualities of the garnet.
1. It is more fusible, in proportion as it contains less metallic matter, and is more transparent or glassy in its texture; which is quite contrary to the filaceous kind.
2. This is the reason, perhaps, why the garnet, mixed with the salt of kelp, may on a piece of charcoal be converted to a glass by the blowpipe, which cannot be done with the flints: and,
3. Why the most transparent garnet may, without any addition, be brought to a black opaque flag by the same means.
4. It is never, so far as is hitherto known, found pure, or without some mixture of metal; and especially iron, which may be extracted by the common methods.
5. The garnet matter, during the crystallisation, has either been formed in small detached quantities, or else has had the power of shooting into crystals, though closely confined in different substances; since garnets are generally found dispersed in other solid stones, and oftentimes in the harder ones, such as quartz and chert.
I. Garnet; *Granatus*. Which is a heavy and hard kind of stone, crystallising in form of polygonal balls, and is mostly of a red, or reddish brown colour.
A. Garnet mixed with iron; *Granatus martialis*.
1. Coarse-grained garnet-stones, without any particular figure; in Swedish called *Granatberg*; in German, *Granatstein*. a. Reddish-brown garnet.
b. Whitish-yellow.
c. Pale yellow.
2. Crystallised garnet.
a. Black.
b. Red: semi-transparent, and cracked; transparent.
c. Reddish yellow transparent; the jacinth, or hyacinth.
d. Reddish brown.
e. Green.
f. Yellowish green.
B. Garnet mixed with iron and tin.
1. Coarse-grained, without any particular figure.
a. Blackish-brown.
2. Chrysoz. Order III.
2. Crystallised. a. Blackish-brown. b. Light-green or white.
The bergs-radets, or mine-masters, Mr Brandt and Mr Rinman, have published some experiments on this kind of garnet, in the Memoirs of the Royal Academy of Sciences at Stockholm.
C. Garnet mixed with iron and lead. 1. Crystallised. a. A reddish-brown, discovered and accurately examined by the bergs-radet Mr Von Swab (c).
II. Cockle, or shirl. Basalter; Corneus crystallifatus Wallerii; Stannum crystallis columnaribus nigris Linnei.—Is a heavy and hard kind of stone, which shoots into crystals of a prismatical figure, and whose chief colours are black or green. Its specific gravity is the same as the garnets, viz. between 3000 and 3400, though always proportionable to their different solidity.
A. Cockle, or shirl, mixed with iron. 1. Coarse, without any determined figure. a. Green, found in most of the Swedish iron mines.
2. Sparry. a. Deep green, (the mother of the emeralds), from Egypt. b. Pale green. c. White.
This occurs very frequently in the scaly limestones; and its colour changes from deep green to white, in proportion as it contains more or less of iron.
3. Fibrous, striated cockle, or shirl: it looks like fibres or threads made of glass. a. Of parallel fibres. a. Black. b. Green. c. White.
b. Of concentrated fibres. The starred cockle, or shirl, from its fibres being laid stellarwise. a. Blackish green, from Salberg, in Westmanland; where, being found together with a steel-grained lead ore, the whole is called grau-ris-malm, or pine-ore, from its resemblance to the branches of that tree. This kind of cockle is also found at Uto in Malaren. b. Light green. c. White.
4. Crystallised cockle, or shirl. a. Black.
To this species of cockle, or shirl, belong most of those substances called imperfect albeiti; and as the cockle perfectly resembles a flag from an iron furnace, both in regard to its metallic contents and its glassy texture, it is no wonder that it is not soft enough to be taken for an albeitis. It has, however, only for the sake of its structure, been ranked among the albeitis. The striated cockle, or shirl, compared to the albeiti, is of a shining and angular surface (though this sometimes requires the aid of the magnifying-glass to be discovered), always somewhat transparent, and is pretty easily brought to a glass with the blow-pipe, without being confused as the pure albeiti seem to be.
b. Deep green, from Salberg in Westmanland. c. Light green, from Enighets-grufvan at Norberg in Westmanland. d. Reddish brown; from Sorvik at Grengie in Westmanland, and Glanshammar in the province of Nerike.
The tauffstein, from Basil, is of this colour, and consists of two hexagonal crystals of cockle grown together in form of a cross: this the Roman Catholics wear as an amulet, and is called in Latin lapis crucifer, or the cross-stone.
It is not impossible that there may be some kinds of cockles, or shirls, which, besides iron, also contain tin or lead, as the garnets: it has been said, that lead has been melted out of a cockle, from Rodbeck's Eng at Umea in Lapland; and it seems likewise very probable that the cockles which are found in the English tin-mines may contain some tin. There are some crystals of cockle found which are fusible to a greater degree than any sort of stone whatsoever: these are always of a glassy texture, and semi-transparent.
The figure of the cockle crystals is uncertain, but always prismatical: the cockle from Yxflo at Nya Kopparberg, is quadrangular: the French kind has nine sides, or planes; and the tauffstein is hexagonal.
The name cockle for these substances is an old Cornish mineral name; but is also given sometimes to other very different matters.
We have not in England any great quantity of species of cockles; the chief are found in the tin mines of Cornwall, and some fine crystallised kinds have been brought from Scotland.
The English mineral name of call, has been used by some authors as synonymous with cockle, and they are confounded together at the mines; but the call, definitely speaking, is the substance called wolfram by the Germans, &c.
Garnets, though small, are often found in micaeous stones in England; but extreme good garnets are found in great plenty also in like stones in Scotland.
The Fourth Order.
The Argillaceous kind.
The principal character whereby these may be distinguished from other earths is, that they harden in the fire, and are compounded of very minute particles, by which they acquire a dead or dull appearance when broken.
I. Porcelain I. Porcelain clay; Terra porcellanea, vulgo Argilla apyra.
This is very refractory in the fire, and cannot in any common strong fire be brought into fusion any farther than to acquire a tenacious softness, without losing its form: it becomes then of a dim shining appearance and solid texture, when it is broke; strikes fire with steel; and has consequently the best qualities required as a substance whereof vessels capable of resisting a melting and boiling heat, and of holding salts and acids, can be made. It is found,
(1.) Pure, Pura.
A Diffusible in water.
1. Cohesive and dry. a. White. Mr Cronstedt affirms that he has seen a root of a tree changed into this clay. 2. Friable and dry. a. White.
These may be called pure, since, after being burnt, they are quite white, though they have been exposed to a quick melting heat; and it may be queried, if all such clays must not be somewhat harsh, or at least unctuous to the touch.
(2.) Mixed with phlogiston, and a very small quantity of inseparable heterogeneous substances.
Of these are,
A. Diffusible in water. a. White and fat pipe-clay. b. Of a pearl colour. c. Bluish grey. d. Grey. e. Black. f. Violet.
These contain a phlogiston which is discovered by exposing them to quick and strong fire, in which they become quite black internally, assuming the appearance of the common flints, not only in regard to colour, but also in regard to hardness; but if heated by degrees, they are first white, and afterwards of a pearl colour. The fatter they seem to be, which may be judged both by their feeling smooth and unctuous, and by their shining when scraped with the nail, they contain a larger quantity of the inflammable principle. It is difficult to determine, whether this strongly inherent phlogiston be the cause of the above-mentioned pearl colour, or prevents them from being burnt white in a strong fire: yet no heterogeneous substance can be extracted from them, except sand, which may be separated from some by means of water, but which sand does not form any of the constituent parts of the clays. If they be boiled in aqua regis in order to extract any iron, they are found to lose their viscoity.
B. Indurated.
Is commonly unctuous to the touch, and more or less difficult to be cut or turned in proportion to its different degrees of hardness; is not diffusible in water; grows hard, and is very refractory in the fire; pounded and mixed with water, it will not easily cohere in a paste: however, if it is managed with care, it may be baked in the fire to a mass, which, being broke, shews a dull and porous texture. It takes for the most part, and without much labour, a fine polish. It is found,
A. Compact and soft; Smelting, Briançon or French chalk. a. White. b. Yellow. c. Red and white, and which looks like Caftile soap.
B. Solid and compact steatites, and also soap-rock. a. White or light green. b. Deep green. c. Yellow.
It is a very difficult matter to specify all the varieties of the soap-flones in regard to their hardness or softness, since they cannot be compared with any standard measure. Those from River, Sikkioberg, and China, are a great deal harder and more solid than the English kind from Land's End, which breaks between the fingers; but are soft in comparison to that from Salberg, which is there called serpentine, although both these varieties may in indiscriminately be made use of for cutting and turning. The soft ones, however, are not apt to crack, when they are worked, as the harder. But none of these varieties is found in the rock, without being interspersed with the unctuous clefs. When they are too many, too close to one another, and make the stone unfit for use, they are in this case called by the Swedish miners, Skioligas; and of this kind is a great quantity found at Salberg and Swartvik. Most part of the soap-rock which is found in Sweden, is likewise mixed with glimmer or mica; and then it is called teigsten, that is, ollaris.
C. Solid, and of visible particles; serpentine stone.
1. Of fibrous and coherent particles. This is composed, as it were, of fibres; and might therefore be confounded with the asbestos, if its fibres did not cohere so closely with one another as not to be seen when the stone is cut and polished. The fibres themselves are large, and seem as if they were twisted. a. Deep green. This is sold for the lapis nephriticus, and is dug at some unknown place in Germany. b. Light green from Skienshyttan, in Västmanland; in Sweden it is used by the plate-smiths instead of the French chalk.
2. Fine-grained serpentine stone: the Zoebitz serpentine. a. Black. b. Deep green. c. Light green. d. Red. e. Bluish grey. f. White.
These colours are all mixed together in the serpentine stone from Zoebitz, but the green is the most predominant colour.
(3.) Mixed with iron. This is,
A. Diffusible in water. a. Red. Some of the bricks which are imported ported from certain places in Germany, seem to be made of this kind.
B. Indurated.
1. Martial soap-earth; Creta Brianzonica martialis. a. Red, and mixed with some calcareous matter. 2. Martial soap-rock; Steatites martialis. a. Black. b. Red.
II. Stone-marrow; Lithomarga. Kefekil of the Tartars.
1. When dry, it is as fat and slippery as soap: but, 2. Is not wholly diffusible in water, in which it only falls to pieces, either in larger bits, or resembles a curd like mats. 3. In the fire it easily melts to a white or reddish frothy flag, consequently is of a larger volume than the clay was before being fused. 4. It breaks into irregular scaly pieces. a. Of coarse particles: Coarse stone-marrow. a. Grey, from Olfmundberget, in the parish of Rettwik, in Dalarna; and is there called ovallkera, that is, fuller's earth. It is mentioned in an account of Olmundberget, published in the Transactions of the Academy of Sciences at Stockholm, in the year 1739, by the berg's-radet, or mine-master, Mr Tilas. b. Whitish yellow, from the Crim Tartary, where it is called keffekil, and is said to be used for washing instead of soap. b. Of very fine particles; fine stone-marrow. a. Yellowish-brown; Terra Lemnia.—Is of a shining texture, falls to pieces in the water with a crackling noise; it is more indurated than the preceding, but has otherwise the same qualities.
III. Bole.
Is a fine and dense clay of various colours, containing a great quantity of iron, which makes it impossible to know the natural and specific qualities of the bole itself, by any easy method hitherto in use. It is not easily softened in water, contrary to what the porcelain and the common clays are, (I. & V.), but either falls to pieces in form of small grains, or repels the water, and cannot be made ductile. In the fire it grows black, and is then attracted by the loadstone.
A. Loose and friable boles, or those which fall to a powder in water. a. Flesh-coloured bole. b. Red. 1. Fine; Bolus Armenus. 2. Coarse; Bolus communis officinalis. 3. Hard; Terra rubrica. 4. Green; Terra verte. 1. Fine. 2. Coarse. d. Bluish-grey, is ductile as long as it is in the rock, but even then repels the water; it contains 40 per cent. of iron; which metal being melted out of it in a close vessel, the iron crystallizes on its surface.
e. Grey. 1. Crystallized in a spherical polygonal figure. 2. Of an undeterminate figure.
At the time when the terre figillate, or sealed earths, were in general use, the druggits endeavoured to have them of all colours, and for that reason they took all sorts of clays, and sealed them; not only the natural ones, but likewise such as had been coloured by art, or had been mixed with magnesia alba officinalis, or other things, were afterwards vended for true boles; and for this reason the species of boles is still thought to comprehend so many varieties. Thus the Cologne clay is by the druggits ranked among the white sealed earths, and is called a white bole: and this same clay is by the Swedish potters called Engelsk jord, or English earth; and by the tobacco-pipe makers pip-lera, or pipe-clay, &c.: which shews how great a confusion there must ensue, if the knowledge of these bodies was not founded upon a surer ground than the colour, figure, and names invented by common mechanics. Since the most part of these terre figillate, or sealed earths, are found to contain iron, we may conclude that the bole must be a martial clay; and, as such, it seems to be more fit for medical uses than other clays, if any dead earth must be used internally, when there is such an abundance of finer substances.
B. Indurated bole.
A. Of no visible particles.
This occurs very often in form of slate, or layers, in the earth; and then is made use of as an iron ore. However, it has usually been considered more in regard to its texture than to its constituent parts; and has been called slate, in common with several other earths which are found to have the same texture. a. Reddish-brown; in most collieries, between the seams of coal. b. Grey; from Coalbrookdale in Shropshire, and most collieries of England. b. Of scaly particles.—The hornblende of the Swedes. Is distinguished from the martial glimmer, or mica, by the scales being less shining, thicker, and rectangular. a. Black.—This, when rubbed fine, gives a green powder. b. Greenish.
Both these, particularly the black, are found everywhere in Sweden among the iron ores, and in the Grunten. The hornblende grows hard in the fire, which is the reason why it is ranked here among the clays, though in all its other qualities it much resembles the cockle or shell.
IV. Tripoli. Terra Tripolitana.
Is known by its quality of rubbing hard bodies, and making their surfaces to shine; the particles of the tripoli being so fine as to leave even no scratches on the surface. This effect, which is called polishing, may likewise be effected by other fine clays when they have been burnt a little. The tripoli grows somewhat harder in the fire, and is very refractory; it is with difficulty dissolved by borax, and still with greater difficulty by the microcosmic salt. It becomes white when it is heated; when crude, it imbibes water, but is not diffusible in it: it tastes like common chalk, and is rough or sandy between the teeth, although no sand can by any means be separated from it. It has no quality common with any other kind of earth, by which it might be considered as a variety of any other. That which is here described is of a yellow colour, and is sold by druggists. This kind of tripoli has been lately discovered in Scotland. But the rotten-stone, so called, is another sort found in England, viz. in Derbyshire. It is in common use in England among workmen for all sorts of finer grinding and polishing, and is also sometimes used by lapidaries for cutting of stones, &c.
V. Common clay, or brick clay. Argilla communis; vulgaris plasica.
This kind may be distinguished from the other clays, by the following qualities.
1. In the fire it acquires a red colour, more or less deep. 2. It melts pretty easily into a greenish glass. 3. It contains a small quantity of iron and of the vitriolic acid, by which the preceding effects are produced.
It is found,
A. Diffusible in water.
1. Pure. a. Red clay. b. Flesh-coloured, or pale-red. c. Grey. d. Blue. e. White, is found in the woody parts of Sodermanland, Dalarne, and of other provinces. It is often found in a flat form, with fine sand between its strata. It is not easy to be baked in the fire: when it is burnt, it is of a pale-red colour, and is more fusible than the preceding ones.
f. Fermenting clay. Argilla intumescens.
This is very like the preceding, as to the external appearance and other qualities; but when they are both found in the same place, which is not uncommon in several of our mine countries, they seem to be different in regard to the fermenting quality of this variety. This fermentation cannot be the effect of the sand mixed with it, because sand is found in them both: and besides, this kind ferments in the same manner when it is mixed with gravel or stones; and then it ferments later in the spring than the other, since by the stones, perhaps, the frost is longer retained in it.
2. Mixed with lime. See MARLE, no 95.
B. Indurated.
1. Pure. a. Grey flaky. b. Red flaky, from Kinnekulle, in the province of Westergötland.
2. Mixed with phlogiston, and a great deal of the vitriolic acid. See ALUM ORES, no 173.
3. Mixed with lime; (no 98).
The Fifth Order.
The Micaceous kinds. The glimmer, daze, or glass.
These are known by the following characters.
1. Their texture and composition consist of thin flexible particles, divisible into plates or leaves, having a shining surface.
2. These leaves, or scales, exposed to the fire, lose their flexibility, and become brittle, and then separate into thinner leaves: but in a quick and strong fire, they curl or crumple, which is a mark of fusion; though it is very difficult to reduce them into a pure glass by themselves, or without addition.
3. They melt pretty easily with borax, the microcosmic salt, and the alkaline salt; and may, by means of the blow-pipe, be brought to a clear glass with the two former salts. The martial mica is, however, more fusible than the uncoloured ones.
There is not yet discovered any loose earth of this kind, but it is always found indurated.
A. Colourless or pure mica; daze, glimmer, or glass.
1. Of large parallel plates; Mucovoy glass. Is transparent as glass; found in Siberia, and Elfdalen in the province of Wermland in Sweden. 2. Of small plates; from Silfverberget, at Runneby, in the province of Blekinge, in Sweden. 3. Of particles like chaff; chaffy mica. 4. Of twisted plates; crumpled mica.
B. Coloured and martial glimmer.
1. Of large parallel plates; Martialis. a. Brown semi-transparent. 2. Of fine and minute scales. a. Brown. b. Deep green. c. Light green; Talcum officinale. d. Black, found in granites. 3. Twisted or crumpled glimmer. a. Light green, in the alaris. 4. Chaffy glimmer. a. Black, is found in the stone called hornberg, which occurs in most of the Swedish copper-mines. 5. Crystalised glimmer; Mica drufica. 1. Of concentrated and erect scales. 2. Of hexagonal horizontal plates.
The Sixth Order.
The fluors, Fluores minerales. Succ. Flussarten. Germ. Flussarten.
These are commonly called fluxing, vitreous, or glass fleurs, because most part of them have a sparry Order VI.
**MINERALOGY.**
Earth's form and appearance: they are, however, often met with in an indeterminate figure.
There are only known in an indurated state; and distinguish themselves from the other earths by the following characters:
1. They are scarce harder than a calcareous spar, and consequently do not strike fire with steel. 2. They do not ferment with acids, neither before nor after calcination, notwithstanding a phlogiston or an alkali had been added in the calcination. 3. They do not melt by themselves, but only split to pieces when exposed to a strong fire. 4. In mixtures with all other earths, they are very fusible, and especially when they are blended with the calcareous earth, with which they melt to a corroding glass, which dissolves the strongest crucibles, unless some quartz or apyrrus clay is added thereto. 5. When heated slowly, and by degrees, they give a phosphorescent light; but as soon as they are made red-hot, they lose this quality. The coloured ones, and especially the green, give the strongest light, but none of them any longer than whilst they are well warm. 6. They melt and dissolve very easily by the addition of borax, and next to that by the microcosmic salt, without ebullition.
A. Indurated fluor.
(1.) Solid, of an indeterminate figure. Is of a dull texture, semi-transparent, and full of cracks in the rock.
a. White.
(2.) Sparry fluor has nearly the figure of spar, though, on close observation, it is found not to be so regular, nothing but the glossy surface of this stone giving it the resemblance of spar.
a. White. b. Blue. c. Violet. d. Deep green. e. Pale green. f. Yellow, from Gillof in Skone.
(3.) Crystallised fluor, when in single crystals; but fluor druse, when many crystals are heaped together.
1. Of an irregular figure.
a. White. b. Blue. c. Red.
2. Of a cubical figure.
a. Yellow. b. Violet.
3. Of a polygonal spherical figure.
a. White. b. Blue.
4. Of an octahedral figure.
a. Clear and colourless.
The Seventh Order.
The Asbestos kind; Asbestinae.
These are only yet discovered in an indurated state: their characters are as follow,
1. When pure they are very refractory in the fire. 2. In large pieces they are flexible. 3. They have dull or uneven surfaces. 4. In the fire they become more brittle. 5. They do not strike fire with the steel. 6. They are not attacked by acids. 7. They are easily brought into fusion by borax.
In this order are included both those varieties which by systematics have been mentioned under the names amianti and asbestos, and have often been confounded together.
I. Asbestos which is compounded of soft and thin membranes; Amiantus Wallerii.
A. Of parallel membranes; Corium, five caro montana, mountain-leather.
1. Pure.
a. White.
2. Martial.
a. Yellowish brown, from Storrginningen, at Dannemora, in the province of Upland.
This melts pretty easily in the fire to a black flag, or glass.
B. Of twisted felt membranes, mountain-cork.
1. Pure.
a. White.
2. Martial.
a. Yellowish brown. This has the same quality in the fire as the martial mountain-leather.
II. Offine and flexible fibres; Asbestos, or earth-flax; Asbestos Wallerii.
A. With parallel fibres; Byssus.
1. Pure and soft.
a. Light green.
b. White.
2. A little martial, and more brittle.
a. Greenish; from Baftnas Grufva, at Rydardarhyttan in Västmanland in Sweden.
There it forms the greatest part of the vein out of which the copper ore is dug; a great part of it is consequently melted together with the ore, and is then brought to a pure semi-transparent martial flag or glass.
B. Of broken and recombined fibres.
1. Martial.
a. Light green.
The Eighth Order.
Zeolites.
This is described in its indurated state, in the Transactions of the Academy of Sciences at Stockholm for the year 1756; and there methodised as a stone sui generis, in regard to the following qualities:
1. It is a little harder than the fluor, and the calcareous kind: it receives however scratches from the steel, but does not strike fire with it. 2. It melts easily by itself in the fire, with a like ebullition as borax does, into a white frothy flag, which not without great difficulty can be brought to a solidity and transparency. 3. It is easier dissolved in the fire by the mineral alkali (cal soda), than by the borax and microcosmic salt. 4. It does not ferment with this last salt, as the lime does; nor with the borax, as those of the gypseous kind. 5. It dissolves very slowly, and without any effervescence, in acids, as in oil of vitriol and spirit of nitre. If concentrated oil of vitriol is poured on pounded zeolites, a heat arises, and the powder... powder unites into a mass (1).
6. In the very moment of fusion it gives a phosphorus or light.
The zeolites is found in an indurated state.
(1.) Solid, or of no visible particles.
A. Pure; Zeolites durus. a. White, from Iceland. B. Mixed with silver and iron. a. Blue; Lapis lazuli, from the Buckarian Calmucks. This, by experiments made with it, has discovered the following properties: 1. It retains for a long time its blue in a calcining heat, but is at last changed into a brown colour. 2. It melts easily in the fire to a white frothy flag; which, when exposed to the flame of a blow-pipe, is greatly puffed up, but in a covered vessel, and with a stronger heat, becomes clear and solid, with blue clouds in it. 3. It does not ferment with acids; but, 4. Boiled in oil of vitriol, it dissolves slowly, and loses its blue colour.
When a fixed alkali is added to this solution, a white earth is precipitated, which being scorified with borax, yields a silver regulus, that varies in bigness according to the various samples of the stone.
5. By scorification with lead, there has been extracted two ounces of silver out of 100 pounds weight of the stone.
6. The presence of silver is not discovered with the same certainty by the spirit of nitre as by oil of vitriol.
7. When the spirit of sal ammoniac is added to any solution, made either of crude or of a perfectly calcined lapis lazuli, there is no blue colour produced; which proves that this colour is not owing to copper, as some have pretended; and this is farther confirmed by the fixity of the blue colour in the fire (1, 2.), and by the colour of the flag or glass (2).
8. It is a little harder than the other kinds of zeolites; but does not, however, in hardness approach to the quartz, or to other stones of the siliceous kind in general; because the purest and finest blue lapis lazuli may be rubbed with the steel to a white powder, although it takes a polish like marble.
9. The lapis lazuli, when perfectly calcined, is a little attracted by the loadstone; and scorified with lead, the flag becomes of a greenish colour, not such a colour as copper gives, but such as is always produced by iron mixed with a calcareous substance.
(2.) Sparry zeolites.
This resembles a calcareous spar; though it is of a more irregular figure, and is more brittle.
a. Light red, or orange-coloured; from Nya
(1) Other varieties of the zeolites have been discovered, particularly at Adelfors's gold-mines in Smoland in Sweden; of which some sorts do not melt by themselves in the fire, but dissolve readily in the acid of nitre, and are turned into a firm jelly.
Krongrufvan, one of the gold-mines at Adelfors, in the province of Smoland.
(3.) Crystallic zeolites is more common than the two preceding kinds; and is found,
A. In groups of crystals in form of balls, and with concentrical points. a. Yellow. b. White.
B. Prismatical and truncated crystals. a. White.
C. Capillary crystals are partly united in groups, and partly separate. In this latter accretion they resemble the capillary or feather silver ore; and is perhaps sometimes called floe ferri, at places where the nature of that kind of stone is not yet fully known.
These crystals are found, a. White.
The Ninth Order.
The Manganese kind; Magnesia.
The stones belonging to this order are in Swedish called brunsten, in Latin sideres, or magnesia nigra; in order to distinguish them from the magnesia alba officinalis, and in French mangonef, &c. They are by some lithographers entirely omitted, and by others ranked among the iron ores.
1. The manganese consists of a substance which gives a colour both to flags and to the solutions of salts, or, which is the same thing, both to dry and to liquid menstrua, viz.
a. Borax, which has dissolved manganese in the fire, becomes transparent, of a reddish brown or jacinth colour. b. The microcosmic salt becomes transparent with it, of a crimson colour, and moulders in the air. c. With the fixed alkali, in compositions of glass, it becomes violet; but if a great quantity of manganese is added, the glass is in thick lumps, and looks black. d. Scorified with lead, the glass gets a reddish brown colour. e. The lixivium of a deflagrated manganese is of a deep red colour.
2. It deflagrates with nitre, which is a proof that it contains some phlogiston.
3. When reckoned to be light, it weighs as much as an iron ore of the same texture.
4. Being melted together with glass-compositions, it ferments during the solution; but it ferments in a still greater degree when it is melted with the microcosmic salt.
5. It does not excite any effervescence with the spirit of nitre; aqua regia, however, extracts the colour out of the black, and dissolves likewise a great deal of it, which, by means of an alkali, is precipitated to a white powder.
6. Such colours as are communicated to glasses by manganese, are easily destroyed by the calx of arsenic oxyn; they also vanish from themselves in the fire.
7. It is commonly of a loose texture, so as to colour the fingers like soot, although it is of a metallic appearance when broke.
Manganese Order IX.
Manganese is found,
Earths: A. Loose and friable, a. Black, seems to be decayed particles of the indurated kind. B. Indurated.
1. Pure, in form of balls, whose texture consists of concentric fibres. a. White, Magnesia alba striata sic dicta, is very scarce. Mr Cronstedt saw a specimen of this kind in a collection from an unknown place in Norway; and by examining a piece of it, he found that it differed from the common manganese, by giving to the borax a deep red colour in the fire: this fort acquires a reddish brown colour when it is calcined.
b. Red manganese is said to be found in Piedmont. This Mr Cronstedt has never seen; but has been told that this variety is free from iron, and gives to glaas rather a red than a violet colour.
2. Mixed with a small quantity of iron. a. Black manganese, with a metallic brightness. This is the most common kind, and is employed at the glaas-houses and by the potters.
It is found, 1. Solid, of a flaky texture; Magnesia tectura vitrea. 2. Steel-grained. 3. Radiated. 4. Crystalized.
a. In form of coherent hemispheres.
3. Blended with a small quantity of iron and tin; Spuma lugi, or Wolfram.
Wolfram is a name which is also sometimes given to mock lead, and sometimes to coke or shirl, as also to other minerals; however, it is chiefly given to this species of manganese, when it occurs in the tin mines.
1. With coarse fibres. a. Of an iron colour. This gives to the glaas compositions, and also to borax and the microcosmic salt, an opaque whitish yellow colour, which at last vanishes.
SECOND CLASS.
The salts. By this name those mineral bodies are called which can be dissolved in water, and give it a taste; and which have the power, at least when they are mixed with one another, to form new bodies of a solid and angular shape, when the water in which they are dissolved is diminished to a less quantity than is required to keep them in solution; which quality is called crystallization.
No other salts ought to be considered and ranked in a mineral system but those which are found natural in the earth; and for this reason a great number of salts will be in vain looked for here, viz. all such as are either natural or prepared by art in the other two kingdoms of nature, and from substances belonging to them. Amongst these is nitre itself and its acid, and the vegetable acid, since these are never had from true mineral bodies; nor is it demonstrated that they have their origin from the true mineral vitriolic and muriatic acids. There have, indeed, been many attempts made to reduce most of them to a vitriolic acid, which by many is called the universal acid: but experiments will not agree with it; at least nobody has yet been able, by uniting a phlogiston with any other acid than the true vitriolic, to produce a sublimate in every particular resembling the true brimstone, or sulphur.
In regard to the known principal circumstances or qualities of the mineral salts, they are divided into
1. Acid salts, or mineral acids. 2. Alkaline salts, or mineral alkalis.
The First Order.
Acid salts; the characters of which are, that they
1. Have a sour taste. 2. Are corrosive; that is to say, have a power of dissolving a great number of bodies. 3. They have a strong attraction to the alkaline salts and earths, whence they always unite with them with an effervescence, and sometimes with a strong heat: by this mixture bodies are produced, which are employed in common life under the names of vitriol, neutral salts, gypsum, &c. 4. They change most of the expressed blue juices of vegetables into red. 5. They separate the alkali from the fat, when they have been united in soap; which effect is called curdling or coagulation. 6. They are volatile and subtile, so as never to be observable by the naked eye, unless they are mixed with heterogeneous bodies; and therefore the figure of the pure mineral acids cannot be defined but by guess.
A. The vitriolic acid; Acidum vitrioli, aluminiis, et sulphatis.
1. The pure vitriolic acid is, in abstract, considered as possible to occur in nature: its qualities, when mixed with water, in which it is caught by distillation, are as follows: 1. When mixed with the least possible quantity of water, it is of an unctuous appearance, and is for that reason improperly called oil of vitriol. 2. It has in that state a considerable heaviness, viz. in comparison to water, as 1700 to 1000. 3. It dissolves silver, tin, the regulus of antimony, and quicksilver; but, 4. When mixed with more water, it dissolves zinc, iron, and copper. 5. It dissolves likewise the calcareous earth, and precipitates with it in form of a gypsum, of which a part shoots into gypseous druses, sclerites et crystalli gypsi. 6. It unites with the earth of quartz, when it has been previously dissolved in the liquor ficicum; and with a pure argillaceous earth, dissolving it without any fermentation: with both these earths it makes alum. 7. It has a stronger attraction to the inflammable substance than to the alkaline salt, and forms with it a body which properly may be called the mineral sulphur. 8. When it is perfectly united with phlogistic substances belonging to the vegetable kingdom, dom, and the water has been completely separated, this mixture catches flame in the open air; and is consumed; as may be seen by the powder called pyrophorus.
9. It attracts water strongly, and the aqueous vapours out of the air; and if a great quantity of water is added to it at once, a strong heat arises.
10. It unites readily and easily with the alkalis, whereby, according to their nature, different compounds are produced, which have obtained the names of tartarum vitriolatus, sal mirabile, and sal ammoniacum fixum.
II. The vitriolic acid mixed or saturated.
A. With metals; Vitriola, vitriols.
a. Simple vitriols.
1. Martial vitriol; green vitriol, or copperas.
This is the common green vitriol, which naturally is found dissolved in water, and is produced in abundance by decayed or calcined marcasites.
2. Copper vitriol; blue vitriol. This is of a deep blue colour, and is found in all ziment waters, as they are called; for instance, at Neufohl in Hungary, in St Johan's mine at Fahlune in the province of Dalarne, at Nya Kopparberg in Valtmanland, and the copper-mines at Wicklow in Ireland, &c. It is, however, seldom perfectly free from an admixture of iron and zinc.
3. Zinc vitriol, is white and clear as alum, and is found at the Ramelsberg in the Hartz, as also in the rubbish at Stollgruvan in Valtmanland in Sweden, where the mock lead has decayed either spontaneously, or after having been burnt.
b. Compound vitriols.
1. Vitriol of iron and copper, is of a bluish green colour.
2. Vitriol of iron, zinc, and copper. This verges more to the blue than to the green colour. It is made at Fahlune in Dalarne, from the water which is pumped out of the copper mines: in this water large crystals of vitriol are often ready formed. If this vitriol is dipped in water, and afterwards rubbed on clean iron, the copper does not precipitate from it.
3. Vitriol of zinc and iron. This is the green vitriol from Goslar in the Hartz.
4. Vitriol of zinc and copper. This is the blue vitriol from Goslar.
5. Vitriol of nickel and iron, is of a deep green colour, and is contained in the ochre or decayed parts of the nickell, at the cobalt-mines at Los, in the province of Helsingland.
Most part of the vitriols owe their formation to art: because when such ores as contain sulphur are dug out of the mines by means of fire, the phlogiston of the sulphur is by the heat expelled, leaving the acid behind; which, being let loose or freed, is thereby enabled to attract and unite with watery vapours, dissolving at the same time the metals; and it is thus the vitriols are formed. Every sort of ore does not commonly decay or weather in a natural manner, without being promoted by art; and this decaying or weathering is mostly performed in the open air: for which reason no very great quantity of vitriol can be expected in that way; for when any ore thus weathers or decays, the dissolved particles are by degrees carried off by the rain, and are at last found in a dissolved state in certain springs or mineral waters. All such ores may therefore be called true vitriol ores, as contain iron, copper, zinc, and nickel mineralised with sulphur. The acid in the vitriols, however, is not dulcified by the metals, as it is by the alkali in the true neutral salts.
B. The acid of vitriol mixed or saturated with earths.
1. With a calcareous earth. Gypsum.
2. With an argillaceous earth. The alum kind.
a. With a small quantity of clay. Native or plumose alum.
Is found on decayed alum ores in very small quantities.
The gypsa and albiti, but more especially the latter, have been used through ignorance in most countries for plumose native alum, on account of the similarity of structure.
b. With a greater quantity of pure clay. White alum ore.
1. Indurated pale red alum ore. Is employed at Lumini, not far from Civita Vecchia in Italy, to make the pale red alum called roche-alum. This is, of all alum ores, the most free from iron; and the reddish earth which can be precipitated from it does not show the least marks of any metallic substance.
c. With a very large quantity of martial clay, which likewise contains an inflammable substance. Common alum ore.
Is commonly indurated and flaky, and is therefore generally called alum plate.
It is found,
1. Of parallel plates, with a dull surface; from Andrarum in the province of Skone, Hunneberg and Billingen in the province of Westergottland, Rodoen in the province of Jemtland, and the island of Oesland, &c.
2. Undulated and wedge-like, with a shining surface. This at first sight resembles pit-coal: it is found in great abundance in the parish of Nas in Jemtland.
c. Vitriolic acid united with phlogiston. The fulphur kind.
D. Vi- Order I.
B. Vitriolic acid saturated with alkaline salt.
a. With the alkali of the common salt or sea-salt.
This is a neutral salt, prepared by nature as well as by art, containing more or less of iron, or of a calcareous earth, from which arises also some difference in its effects when internally used. It shoots easily into prismatic crystals, which become larger in proportion to the quantity of water evaporated before the crystallization. When laid on a piece of burning charcoal, or else burnt with a phlogiston, the vitriolic acid discovers itself by the smell like to the kepar sulphuris.
It is found in a dissolved state in springs and wells, and in a dry form on walls, in such places where aphronitrum has effloresced through them, and the vitriolic acid has happened to be present; for instance, where marcasites are roasted in the open air. This salt is often confounded with the aphronitrum, or a pure mineral alkali; and a learned dispute once arose, which of these salts ought with the greatest propriety to be called natron, Baurach vetrum, sal mirabile, or Epsom salt; whereas it might easily have been decided by chemical experiments, if their qualities had been regarded in preference to their figures or their native places.
This may be called English or Epsom salt, when it has naturally as equal a copious portion of the calcareous earth as of the artificial one; but in regard to its effects, for which it has been most valued by Glauber, Mr Cronstedt has ranked all the less considerable varieties of this neutral salt, when natural, under the name of salmirabile.
B. Acid of common or sea-salt. This acid, considered in that state in which it can be had, viz. in mixture with water, has the following qualities:
1. It does not alter the fluidity of water, nor considerably augment its heaviness, as the vitriolic acid does.
2. It is somewhat less corrosive and four than the said vitriolic acid.
3. It strongly attracts the alkaline salts; but, however, is forced to quit them to the vitriolic acid, when that is added.
4. It dissolves the calcareous earth, and makes with it a substance called sal ammoniacum fixum.
5. When exposed to the fire, combined with a phlogiston, it burns with a yellowish green flame.
6. When highly concentrated and pure, as when it is distilled from common salt mixed with pipe-clay, it dissolves tin and lead; but less pure, it dissolves copper, iron, zinc, and the regulus of antimony; the copper is, however, more easily dissolved when it is in form of a calx, as the calces of quicksilver and cobalt likewise are.
7. It unites with silver dissolved in aquafortis, and with lead dissolved in aqua-regia, falling with them to the bottom in form of a white spongy mass. This precipitation, exposed to the fire, still retains the acid, and melts with it into a glassy substance, which does not dissolve in water.
8. It is apt to attract the humidity of the air, and to promote the decaying of those dry substances with which it has been united.
9. Mixed with the spirit of nitre, it makes the solution called aqua-regia, which is the true liquid menstruum for gold.
This acid seems also, on certain occasions, to have got loose from those substances with which it had been originally united in the earth: the sal ammoniacum naturale at Solfatara in Italy, and the horn silver ore, appear to be proofs of this, as they seem to be the products of time.
I. Mixed or satiated acid of sea-salt.
a. With earths.
1. With a calcareous earth; sal ammoniacum fixum.
This somewhat decays, or attracts the humidity of the air: it is found in abundance in the sea-water. See the calcareous kind, (91, &c.)
b. With alkaline salts.
(1.) With the fixed mineral alkali, or sea alkali; common salt, or sea-salt.
This shoots into cubical crystals during the evaporation; it crackles in the fire, and attracts the humidity of the air.
a. Rock salt, fossil salt.
Occurs in form of solid strata in the earth.
1. With fealy and irregular particles.
a. Grey, and
b. White. These are the most common, but the following are scarcer:
c. Red,
d. Blue, and
e. Yellow, from Cracow in Poland, England, Salzberg, and Tirol.
2. Crystallized rock-salt.
a. Transparent, from Cracow in Poland, &c.
b. Sea-salt.
Is produced from sea-water, or from the water of salt lakes, by evaporation in the sun, or by boiling.
The seas contain this salt, though more or less in different parts. In Siberia and Tartary, there are lakes that contain great quantities of salt.
2. Spring-salt.
(2.) Saturated with a volatile alkali. Native sal-ammoniac.
This is of a yellowish colour, and is sublimed from the flaming vents or crevices at the Solfatara near Naples.
c. United with phlogiston; amber, succinum.
d. United with metals.
1. With silver; Minera argenti cornea, horn silver ore. The hornetz of the Germans.
The Second Order.
ALKALINE mineral salts.
There are known by their action on the above-mentioned acids when they are joined together, whereby, whereby a fermentation arises, and a precipitation ensues of such bodies as either of them had before kept in dissolution, uniting at the same time together; by which new compositions are made, that are called neutral salts, or salia neutra.
These alkaline salts are,
I. Fixed in the fire.
A. Alkali of the sea, or of common salt.
(1.) Pure.
This has nearly the same qualities with the lixivious salt which is prepared from the ashes of burnt vegetables; it is the same with the sal fidei, or kelp, because the kelp is nothing else than the ashes remaining after the burning of certain herbs that abound with common salt; but which common salt, during the burning of those vegetables, has quitted its acid.
This, 1. Ferments with acids, and unites with them. 2. Turns the syrup of violets to a green colour. 3. Precipitates sublimate mercury in an orange-coloured powder. 4. Unites with fat substances to make soap. 5. Dissolves the siliceous earth in the fire, and makes glass with it, &c. It distinguishes itself from the salt of the pot-ashes, by the following properties: that, 6. It shoots easily into prismatical crystals; which 7. Fall to powder in the air, in consequence of their easily losing their humidity. 8. Mixed with the vitriolic acid, it makes the sal mirabile. 9. It melts easier; and perhaps it is also more conveniently applied in the preparation of several medicines. 10. It is somewhat volatile in the fire.
(2.) Mixed with a small quantity of the calcareous earth.
This is so strongly united with the calcareous earth, that the latter enters with it into the very crystals of the salt: though, by repeated solutions, the earth is by degrees separated from it, and falls to the bottom after every solution. It grows in form of white frost on walls, and under vaults, and in places where it cannot be washed away by the rain. When it contains any considerable quantity of the calcareous earth, its crystals become rhomboidal, a figure which the calcareous earth often assumes in shooting into crystals; but when it is purer, the crystals shoot into a prismatical figure. This is a circumstance which necessarily must confuse those who know the salts only by their figure, and shews at the same time how little certainty such external marks afford in a true distinction of things. This salt is therefore very often confounded with the sal mirabile.
(3.) Saturated with mineral acids. Neutral salts.
B. Borax.
Many experiments have been made with this salt, in order to discover its origin and constituent parts, the most remarkable of which are mentioned under the article Chemistry No. 170, and its following qualities are to be observed.
1. It swells and froths in the fire, as long as any humidity remains in it; but melts afterwards very easily to a transparent glass, which, as it has no attraction to the phlogiston, keeps itself in the form of a pearl on the charcoal when melted with the blowpipe.
2. It changes the syrup of violets into green; and precipitates the solution of alum, and that of metals made with acids.
3. It unites with mineral acids to a neutral salt, which shoots into very fine and subtile hair-like crystals, and is called sal fedativum. In a certain composition it is volatile; and mixed with limmus, or succus heliotropii, and the syrup of violets, it discovers marks both of an alkali and an acid.
4. When it has been united with the vitriolic acid and a phlogiston, no hepatic sulphur is produced.
5. After being refined, it shoots into irregular figures; but the crystals, which form themselves after the first operation, and are called tincal, consist of octagonal prisms, flat at the extremities, and with their angles cut off or truncated.
II. Volatile. This perfectly resembles that salt which is extracted from animals and vegetables, under the name of alkali volatile, or sal urinosa, and is commonly considered as not belonging to the mineral kingdom; but since it is discovered not only in most part of the clays, but likewise in the sublimations at Solfatara near Naples, it cannot possibly be quite excluded from the mineral kingdom.
Its principal qualities are, That,
a. In the fire it rises in a dry form, and volatilizes in the air in form of corrosive vapours, which are offensive to the eyes and nose.
b. It precipitates the solution of the mercurial sublimate into a white powder.
c. It also precipitates gold out of aqua regia, and detonates with it.
d. It has a reaction in regard to the acids, tho' not so strongly as other alkalies.
e. It tinges the solution of copper blue, and dissolves this metal afresh, if a great quantity is added.
f. It deflagrates with nitre, which proves that it contains a phlogiston.
It is never found pure; but,
A. Mixed,
1. With salts. a. With the acid of common salt. Native sal ammoniac. 2. With earths.
a. Clay. Class III.
Mineral Inflammable Substances.
To this class belong all those subterraneous bodies that are dissoluble in oils, but not in water, which they repel; catch flame in the fire; and are electrical.
It is difficult to determine what constitutes the difference between the purer sorts of this class, since they all must be tried by fire, in which they all yield the same product; but those which in the fire show their differences by containing different substances, are here considered as being mixed with heterogeneous bodies: that small quantity of earthy substance, which all phlogiston leave behind in the fire, is, however, not attended to.
I. Ambergrise, is commonly reckoned to belong to the mineral kingdom, although it is said to have doubtful marks of its origin.
a. It has an agreeable smell, chiefly when burnt. b. It is consumed in an open fire. c. It softens in a gentle degree of heat, so as to stick to the teeth like pitch. d. It is of a black or grey colour, and of a dull fine-grained texture. The grey is reckoned the best, and is sold very dear.
II. Amber. Ambra flavia; succinum; eleftrum. There are often found fish, insects, and vegetables included in it, which testify its once having been liquid. It is more transparent than most part of the other bitumens, and is doubtless that substance which first gave rise to electrical experiments.
Its varieties are reckoned from the colour and transparency: it is found,
A. Opake. a. Brown. b. White. c. Blackish.
B. Transparent. a. Colourless. b. Yellow. The greatest quantity of European amber is found in Prussia; but it is, besides, collected on the sea-coast of the province of Skone, and at Biorko, in the Lake Malaren, in the province of Upland; as also in France and in Siberia. It is chiefly employed in medicines, and for making varnishes.
III. Rock-oil; Petroleum. It is an inflammable mineral, of a light-brown colour, which cannot be decompounded, but is often rendered impure by heterogeneous admixtures. In length of time, it hardens in the open air, like a vegetable resin; and then becomes of a black colour, whether it is pure, or mixed with other bodies. It is likewise found in the earth.
A. Liquid. 1. Naphtha. This is said to be of a very fragrant smell, transparent, extremely inflammable, and attracts gold. It is gathered from the surface of the water in some wells in Persia.
2. Rock-oil; Petroleum, properly so called. This smells like the oil of amber, though more agreeable, and is likewise very ready to take fire. It is collected in the same manner as the naphtha, from some wells in Italy, and in a deserted mine at Ofsmundberg in the province of Dalarna in Sweden: at this last-mentioned place it is found in small hollows in the limestone, as resin is in the wood of the pines.
B. Thick and pitchy rock-oil, or Barbadoes tar; Petroleum tenax; maltha. Resembles soft pitch.
C. Hardened rock-oil; Petroleum induratum. Fossil pitch; Pix montana.
1. Pure; Asphaltum. This leaves no ash or earthy substance when it is burnt. From this or the preceding substance, it is probable the asphaltum was prepared that the Egyptians used in embalming their dead bodies, and which is now called mummia.
2. Impure; Pix montana impura. This contains a great quantity of earthy matter, which is left in the retort after distillation, or upon the piece of charcoal if burnt in an open fire; it coheres like a flag, and is of the colour of black lead; but in a calcining heat this earth quickly volatilizes; so that the nature of it is not yet known. The substance which rises, and then falls into the receiver during the distillation of this fossil pitch, is entirely the same as the common natural liquid rock-oil.
IV. Mineral phlogiston, or bitumen, united with the vitriolic acid. Sulphur, or brimstone. This is very common in the earth, and discovers itself in many and various forms. It is found,
A. Native sulphur. In this the two constituent parts are mixed in due proportion in regard to each other, according to the rules of that attraction which is between them; it is easily known,
1. By its inflammability, and by its flame. 2. By its smell when burnt; and, 3. By its producing a liver of sulphur, when mixed with a fixed alkali, like that made from artificial sulphur.
It is found,
a. Pellucid, of a deep yellow colour. b. Opake, white, and greyish. It is often found on limestone, which the vitriolic acid has left untouched, having a stronger attraction to the phlogiston, and therefore wholly uniting with that.
B. Sulphur that has dissolved or is saturated with metals.
1. With iron. Pyrites, or copperas-stone; Pyrites. This is the substance from which most sulphur is prepared, and is therefore ranked here with all its varieties. It is hard, and of a metallic shining colour.
a. Pale yellow pyrites; Pyrites subflavus. Marcasite. This is very common, and contains a proportionable quantity of sulphur with respect to the iron; when once thoroughly inflamed, it burns by itself. a. Of a compact texture; Polita piedra del yugo, Hispanorum.
b. Steel-grained.
c. Coarse-grained.
d. Crystalized. It floats mostly into cubic and octohedral figures, tho' it also crystallizes into innumerable other forms.
b. Liver-coloured marcasite. Its colour cannot be described, being betwixt that of the preceding marcasite, and the azure copper ore. The iron prevails in this kind; it is therefore less fit to have sulphur extracted from it, and also for the smelting of copper ores. It is found,
a. Of a compact texture.
b. Steel-grained.
c. Coarse-grained.
2. Iron and tin. Black-lead, or wadd; Molybdena. If by such a mixture as this the iron and tin be not rendered too volatile, it must be supposed that the great loss the black lead suffers in the calcining heat is occasioned from the sulphur, and that the sulphur consequently makes out the greatest part of the black lead. It is found,
a. Lamellar and shining, of the same colour as the potters lead ore.
b. Of a steel-grained and dull texture. It is naturally black, but when rubbed it gives a dark lead colour.
c. Of a fine scaly and coarse-grained texture; coarse black lead. It has at the same time a scaly and a granulated appearance. From Gran in the province of Upland, and from Tavastehuslan in Finland. Professor Pott has examined the black lead in covered vessels, and Mr Quilt in an open fire; from which difference in the method of treating it, different notions have arisen: because the black lead is nearly unalterable when exposed to the fire in covered vessels, or when immediately put into a strong charcoal fire, but it is almost wholly volatile in a calcining heat. This is the case with several others of the mineral phlogistics; and from this we may in general learn, how necessary it is to examine the mineral bodies by many and different methods, and to endeavour to multiply the experiments more than what has been hitherto done.
3. Sulphur with iron and copper; yellow or marcasitical copper ore.
4. Sulphur with iron and lead; potters lead ore.
5. Sulphur with iron and zinc; mock lead, black jack, or blende.
6. Sulphur with iron and arsenic; arsenical pyrites.
7. Sulphur with iron and cobalt.
8. Sulphur with iron and bismuth.
9. Sulphur with iron and nickel.
10. Sulphur with iron and gold; pyritical gold ore.
11. Sulphur with silver; glass silver ore.
12. Sulphur with copper; grey or vitreous copper ore.
13. Sulphur with lead; potters lead ore.
14. Sulphur with bismuth.
15. Sulphur with quicksilver; cinnabar.
16. Sulphur with arsenic, orpiment, realgar.
V. Mineral phlogiston united with earths.
A. With a calcareous earth.
1. With pure calcareous earth; the fetid or fumine spar.
2. With the calcareous earth and vitriolic acid; the leberstein or liverstone of the Swedes.
B. With an argillaceous earth.
1. With a small quantity of argillaceous earth and vitriolic acid; Coal; Lithantrax. It is of a black colour, and of a shining texture; it burns, and is mostly consumed, in the fire; but leaves, however, a small quantity of ashes.
a. Solid coal.
b. Slaty coal.
2. With a greater quantity of argillaceous earth and vitriolic acid; the kalm of the Swedes. This is of the same appearance with the former, though of a more dull texture; it burns with a flame, and yet is not consumed, but leaves behind a flag of the same bulk or volume as the coal was.
3. With abundance of argillaceous earth; stone coal. It burns with a flame by itself, otherwise it looks like other slates.
VI. Mineral phlogiston mixed with metallic earths.
This is not found in any great quantity: in regard to its external appearance, it resembles pit-coal; and the fat substance contained in it, at times, partly burns to coal, and partly volatilizes in a calcining heat.
The only known varieties of this kind are,
A. Minera cupri phlogistica.
When it has been inflamed, it retains the fire, and at last burns to ashes, out of which pure copper can be melted.
B. Minera ferri phlogistica.
This is not very different in its appearance from the pit-coal or fossil pitch, but it is somewhat harder to the touch. There are two varieties of this species:
1. Fixed in the fire; Minera ferri phlogistica fixa.
Exposed to a calcining heat, it burns with a very languid though quick flame; it preserves its bulk, and loses only a little of its weight. It yields above 30 per cent. of iron.
a. Solid, resembles black sealing-wax.
It is found in the liver-coloured marcasite in Waskberget, at Norrberke in Westmanland.
b. Cracked, and friable.
2. Volatile in the fire.
This is unalterable in an open fire, either of charcoal, or even upon a piece of charcoal before the flame of the blow-pipe; but under a muffle the greatest part of it volatilizes, so that only a small quantity of calx of iron remains. It is found,
a. Solid.
b. Cracked.
This last kind leaves more ashes: these ashes, ashes, when farther exposed to the fire, become first yellowish-green, and afterwards reddish-brown; when, besides iron, they then also discover some marks of copper; it has, however, not been possible to extract any metallic substance from them, the effects of the loadstone, and the colour communicated to the glass of borax, having only given occasion to this suspicion.
FOURTH CLASS.
METALS.
Are those mineral bodies which, with respect to their volume, are the heaviest of all hitherto-known bodies; they are not only malleable, but they may also be decomposed, and in a melting heat be brought again to their former state, by the addition of the phlogiston they had lost in their decomposition.
Those metals which in a calcining heat lose their phlogiston, and consequently with that the former coherency of their particles, are called imperfect; as tin, lead, copper, and iron, and all the semi-metals (of which more hereafter): notwithstanding which, they may be malleable. But those which cannot be destroyed in the fire alone are called perfect; as gold, silver, and platina del pinto. Nevertheless, the metals have commonly been considered more with regard to their malleability than to their fixity in the fire; and are therefore divided into,
A. Malleable, which are called metals; and, B. Brittle, which are called semi-metals.
The zinc is, however, as a medium between these two divisions, just as the quicksilver is between the perfect and imperfect metals; because the quicksilver may indeed be so far destroyed in the fire, that its particles are separated during their volatilisation; but every one of them, even the minutest, retains, however, the phlogiston united with it.
The First Order. True Metals.
I. GOLD; Aurum, sol chymicorum.
This is by mankind esteemed as the principal and first among the metals; and that partly for its scarcity, but chiefly for the following qualities:
1. It is of a yellow shining colour. 2. It is the heaviest of all known bodies, its specific gravity to water being as 19,640 to 1000. 3. It is the most tough and ductile of all metals; because one grain of it may be stretched out so as to cover a silver wire of the length of 98 yards, by which means \(\frac{1}{3500}\) grain becomes visible to the naked eye. 4. Its softness comes nearest to that of lead, and consequently it is but very little elastic. 5. It is fixed and unalterable in air, water, and fire, because it does not easily quit its phlogiston; its liquid menstruum being only made by art.
It has, however, according to Homberg's experiments, when exposed to Tschirnhausen's burning-glass, been found partly to volatilise in form of smoke, and partly to scorify: but this wants to be farther examined. It is also said, that gold, in certain circumstances, and by means of certain artifices in electrical experiments, may be forced into glass; and that on this occasion it becomes white, leaving a black dust behind it; which, if so, confirms certain other chemical experiments, viz. That gold can, together with its colour, lose something of its phlogiston, and yet retain its heaviness, ductility, &c.
6. When melted, it reflects a bluish-green colour from its surface. 7. It dissolves in aqua regia, which is composed of the acids of sea-salt and nitre; but not in either alone, nor in any other solution of salt or acid whatsoever. 8. When mixed with a volatile alkali and a little of the acid of nitre, by means of precipitation out of aqua regia, it burns off quickly, in the least degree of heat, with a strong fulmination. 9. It is dissolved, in forma ficca, by the liver of sulphur, and also somewhat by the glass of bismuth. 10. It is not carried away by the antimony during the volatilisation of that semi-metal, and is therefore conveniently separated from other metals by the help of crude antimony; in which process the other metals are partly made volatile, and fly off with the antimony, and partly unite with the sulphur, to which the gold has no attraction, unless by means of some uniting body, or by a long digestion. 11. The phosphorus is said to have ingress into gold. 12. If mixed with a less portion of silver, platina, copper, iron, and zinc, it preserves tolerably well its ductility. But, 13. When mixed with tin, it becomes very brittle; and it attracts likewise the smoke of that metal so as to be spoiled, if melted in an hearth where tin has been lately melted: And this is perhaps the reason why gold becomes brittle, and of a paler colour, when melted in a new black lead crucible. 14. It requires a strong heat before it melts, nearly as much, or a little more than copper. 15. It mixes or amalgamates readily with quicksilver.
A. Native gold is in its metallic form commonly pure: and in this state most part of this metal used in the world is found. With respect to either the figure or the quantity in which it is found in one place, it is by miners divided into,
1. Thin superficial plated or leaved gold; which consists of very thin plates or leaves, like paper. 2. Solid or massive, is found in form of thick pieces. 3. Crystallised, consists of an angular or crystalline figure. 4. Wash gold, or gold dust, is washed out of sands, wherein it lies in form of loose grains. and lumps. The gold is in general more frequently imbedded and mixed with quartz than with any other kind of stone; and the quartz in which the gold is found in the Hungarian gold mines is of a peculiar appearance. All other sorts of stones, however, are not to be excluded, since gold is likewise found in some of them; for instance, in limestone, in Adolph Fredrik's Gruva at Adelfors in the province of Smoland in Sweden; in Hornblende, in Battnas Gruva at Riddarhyttan in the province of Valtmanland; not to mention several other gold mines.
B. Mineralised gold. This is an ore in which the gold is so far mineralised, or so entangled in other bodies, as not to be dissolved by the aqua regia:
1. Mineralised with sulphur. a. Mineralised by means of iron. Marcasite gold ore; Pyrites aureus. It is found at Adelfors, in the province of Smoland; and contains an ounce of gold, or less, in 100 pounds. b. Mineralised by means of quicksilver. It is found in Hungary. c. Mineralised by means of zinc and iron; Aurum sulphure mineralisatum mediathe zince & ferro, aut argento. The Schemnitz blende. At Schemnitz in Hungary are found zinc ores, which contain a great deal of silver, and this silver is very rich in gold. Since gold and sulphur have no immiscible power or attraction to one another, many have insisted that gold never could be found in marcasite, or those ores which contain sulphur; but since we know by experience that gold can be melted out of the above-mentioned ores, although they have been previously digested in aqua-regia; and that gold likewise mixes and dissolves into a regulus; there is the greatest reason to believe that a third substance, which here is a metal, must necessarily have by its admixture enabled the sulphur to unite with a certain quantity of gold. Scheffer has given upon this subject some very curious and useful observations, in his History of the Refining of Metals, inserted in the Transactions of the Academy of Sciences at Stockholm.
It is, however, by no means hereby intended to confirm the credulous in their opinion, that the marcasites in general contain more gold than what true metallurgists have asserted; because fraud might then perhaps become too common. It is only meant to indicate, that, as no gold is to be expected from marcasites, where no native gold is found in the neighbourhood, in the same manner no marcasites ought to be despised which are found in tracks where gold ores are dug; but at the same time care must be taken not to be deluded by the mention of volatile gold, as it is a notion really contradictory and suspicious; and then there can be no fear of being misled.
II. Silver; Argentum, luna. Which is,
a. Of a white shining colour. b. Its specific gravity to water is 11,091 to 1000. c. It is very tough or ductile, so that a grain of it may be stretched out to three yards in length, and two inches in breadth. d. It is unalterable in air, water, and fire. e. It dissolves in the acid of nitre, and also by boiling in the acid of vitriol. f. If precipitated out of the acid of nitre with the common salt, or with its acid, it unites so strongly with this last acid, that it does not part from it, even in the fire itself, but melts with it into a mass like glass, which is called luna cornea. g. It does not unite with the semi-metal nickel, during the fusion. h. It amalgamates easily with quicksilver. i. It is in the dry way dissolved by the nitre of sulphur. k. It has a strong attraction to sulphur, so as readily to take a reddish yellow or black colour, when it is exposed to sulphureous vapours. l. It has no attraction to arsenic; whence, when the red arsenical silver ore, or rothgulden ertz of the Germans, is put into the fire, the arsenic flies off, and leaves the sulphur (which in this compound was the medium unions) behind, united with the silver in form of the glass silver ore, or glass ertz. m. It is not dissolved by the glass of lead, and consequently it remains on the cupel. n. It is exhaled or carried off by volatile metals and acids, as by the vapours of antimony, zinc, and the acid of common salt. o. It melts easier than copper.
Silver is found,
A. Native or pure. Native silver most generally is nearly of sixteen carats standard.
1. Thin superficial plated or leaved silver. 2. It is also found in form, a. Of snaggles, and coarse fibres. b. Of fine fibres. Capillary silver. c. Arboraceous. From Potosi in America, and Kongsberg in Norway. d. Crystaline, or figured. This is very scarce to be met with; it has distinct figures, with shining surfaces; it is, however, sometimes found at Kongsberg.
The silver from America is said to be found for the most part native; so it is likewise at Kongsberg in Norway; but it is not commonly so in the other European mines. In Sweden, it is found native in a very small quantity, in the mines of Salberg in Valtmanland, of Lofoten in Dalarna, of Hevafjord, and Sladkier in the province of Dal, of Sunnerfjord in the province of Smoland, and in the island Utoen in the Lake Malarern. It was once found in pretty large lumps in a vein. vein of clay in one of the iron mines at Normark, in the province of Wermeland. It was there mixed with nickel, which was partly decayed or withered; and under this circumstance it formed the compound ore called the *stercus argentinum* or *goose-dung ore*. At this place the argillaceous vein crosses the veins of the iron ore, and will perhaps be found to have more of these riches, even in several other places, if well searched, as is done in other countries, oftentimes not on such evident marks or signs.
**B. Dissolved and mineralised.**
(1.) With sulphur alone. Glass silver ore,
This is ductile, and of the same colour as lead; but, however, becomes blacker in the air. It has, therefore, very undefendedly got the name of glass-ore; for that name rather belongs to the minera argentii cornea, or horn silver ore, if indeed any silver ore can be considered as glassy.
It is found in the same manner as native gold; viz.
1. In crusts, plates, or leaves. 2. Grown into
a. Snags, and b. Chrysaline figures.
It is generally either of a lamellar or a grained texture, and is found at Kongberg and in the Saxon mines.
The glass silver ore is the richest of all silver ores; since the sulphur, which is united with the silver in this ore, makes out but a very small quantity of its weight.
(2.) With sulphur and arsenic. The red or ruby-like silver ore. The rothgulden of the Germans.
The colour of this ore varies as the proportion of each of these ingredients varies in the mixture; viz. from dark grey to deep red; but when it is rubbed or pounded, it always gives a red colour. When put in the fire, it crackles and breaks; and when the crackling ceases, it melts easily, the arsenic at the same time exhaling in smoke.
a. Grey arsenical silver ore: which is either, 1. Plated, crustled, or leaved; and, 2. Solid. b. The red arsenical silver ore: 1. Plated, crustled, or leaved; 2. Solid or scaly; and, 3. Crystalised.
In this last form it shows the most beautiful red colour, and is often semi-transparent. It contains about 60 per cent. in silver; and is found in the greatest quantity at Andreasberg in the Hartz.
(3.) With sulphurated arsenic and copper. The weissgulden of the Germans.
This, in its solid form, is of a light grey colour, and of a dull and steel-grained texture. The more copper it contains, the darker is the colour. It often holds seven pounds of silver per cent. It is,
a. Friable, withered, or decayed, of a black or footy colour; and is therefore by the Germans called *silber-schwartz*, or *Rüffig-tes-ertz*.
b. Solid, of a light grey colour, and is that fort properly called *weissgulden*.
It is found at St Mary of the Mines in Alsfatia, the Saxon mines, and at St Andreasberg in the Hartz.
(4.) With sulphurated arsenic and iron. The *weissertz*, or white silver ore, of the Germans.
This is an arsenical pyrites, which contains silver; it occurs in the Saxon mines, and so exactly resembles the common arsenical pyrites as not to be distinguished from it by sight alone, or without other means. The silver it contains may perhaps consist of very subtle capillary silver mixed in it.
(5.) With sulphurated antimony.
a. Of a dark-grey and somewhat brownish colour. The *leberertz*, from Braunsdorf in Saxony. b. Of a blackish blue colour.
1. In form of capillary crystals. *Federertz*, or plumose silver ore.
It is found in Saxony, and contains only two or four ounces of silver per cent.
(6.) With sulphurated copper and antimony. The Dal falertz.
This resembles, both in colour and texture, the dark-coloured weissgulden, or falertz. When rubbed, it gives a red powder.
a. Solid. b. Crystalised, is found in the parish of Aminikog in the province of Dal; and at that place has been for several years melted by a method invented for the different mixture of the ores; which process must be very troublesome to those who are not perfectly well versed in metallurgy.
It contains 13 ounces of silver, and 24 per cent. of copper.
(7.) With sulphurated zinc. The pechblende of the Germans.
This is a zinc ore, mock lead, or blende, which contains silver, and is found among rich silver and gold ores; for instance, in the Hungarian and Saxon mines.
a. Of a metallic changeable colour:
1. Solid, and with fine scales. 2. In form of balls. The *kugel-ertz*, or ball ore.
It is found at Schemnitz, and contains also gold. Its yield of silver is 24 ounces per cent. and 30 per cent. of zinc.
b. Black mock lead, or blende, found in Saxony. This is also found,
1. Solid, and with fine scales; 2. And in form of balls.
(8.) With sulphurated lead; potters ore. *Galen*, *bleeglanz*.
(9.) With... (9.) With sulphurated lead and antimony, called striperz.
(10.) With sulphurated iron. Silberhaltiger kies; marcasite holding silver.
At Kongberg in Norway, it is said, a liver-coloured marcasite is often found, particularly at the mine called Fraulein Christiana, &c. This marcasite contains of silver from three ounces to three and an half per cent.
(11.) With the acid of common salt. Minera argenti cornua. Hornertz, or horn-silver ore.
This is the rarest silver ore; it is of a white or pearl colour, changeable or varying on the surface, semi-transparent, and somewhat ductile both when crude and when melted. It cannot be decomposed without some admixture of such substances as attract the acid of the sea-salt. It is found in very thin wrought leaves or crusts, at Johan Georgenstadt, in Saxony.
III. Platina del Pinto; Juan blanca.
This metal is a recent discovery of our times; and is described with great accuracy by Scheffer, in the Acts of the Royal Academy of Sciences at Stockholm for the year 1752; as also by Dr Lewis, in the Philosophical Transactions for the year 1754, vol. xlviii. And though these two gentlemen agree in the principal circumstances relating to this metal, yet it is very plain by their descriptions, that neither of them knew anything of the other's experiments. By these descriptions we are convinced of the resemblance this metal bears to gold; and therefore we must allow it to be called white gold, though, both theoretically and practically, it may be distinguished from gold by the following qualities.
1. It is of a white colour.
2. It is so refractory in the fire, that there is no degree of heat yet found by which it can be brought into fusion by itself, the burning-glass excepted, which has not yet been tried. But, when mixed with other metals and semi-metals, it melts very easily, and especially with arsenic, both in its metallic form and in form of a calx or glass.
3. It does not amalgamate with quicksilver by itself, but only by means of the acid of common salt after a long trituration. This metal is therefore really separated from gold by amalgamation, at those places where it is found; and without this quality it would be very difficult to separate it.
4. It is harder and less coherent than gold.
5. It is heavier than gold; and therefore the heaviest of all bodies hitherto discovered: for though the specific gravity of platina, in the hydrostatical experiments made by Dr Lewis, is found to be to water only as 17,000 to 1000; yet, when melted with other certain metals, its specific gravity has, by an exact calculation, been found to be considerably augmented, even so much as to 22,000.
6. Dissolved in aqua regia, and precipitated with tin, or with a solution of that metal, it yields no purpura mineralis.
Except these, this metal has the same qualities as gold; but it cannot, on account of its refractoriness in the fire, be worked off pure on the cupel, nor can it be worked with antimony; because, before it is rendered perfectly pure, it cools, grows hard, and retains always some part of the added metals. It is brought to us only in its native state, in small, irregular, rugged grains; and it is yet uncertain whether it is found naturally mineralised. The platina is brought to Europe from the Rio del Pinto, in the Spanish West Indies.
IV. Tin; Stannum; Jupiter.
This is distinguished from the other metals by the following characters and qualities.
a. A white colour, which verges more to the blue than that of silver.
b. It is the most fusible of all metals; and,
c. The least ductile; that is, it cannot be extended or hammered out so much as the others.
d. In breaking or bending it makes a crackling noise.
e. It has a smell particular to itself, and which cannot be described.
f. In the fire it is easily calcined to white ashes, which are 25 per cent. heavier than the metal itself. During this operation, the phlogiston is seen to burn off in form of small sparkles among the ashes, or calx.
g. This calx is very refractory; but may, however, with a very strong degree of heat be brought to a glas of the hard resin. But this calx is easily mixed in glas compositions, and makes with them the white enamel.
h. It unites with all metals and semi-metals; but renders most of them very brittle, except lead, bismuth, and zinc.
i. It amalgamates easily with quicksilver.
k. It dissolves in aqua-regia, the spirit of sea-salt, and the vitriolic acid; but it is only corroded into a white powder by the spirit of nitre.
The vegetable acid, soaps, and pure alkaline salts, also corrode this metal by degrees.
l. Its specific gravity to water is as 7400 to 1000, or as 7321 to 1000.
m. Dissolved in aqua-regia, which for this purpose ought to consist of equal parts of the spirit of nitre and sea-salt, it heightens the colour of the cochineal, and makes it deeper; for otherwise that dye would be violet.
Tin is not found naturally in the earth in any other state than,
(i.) In form of a calx.
A. Indurated, or vitrified.
1. Mixed with a little of the calx of arsenic.
A. Solid tin ore, without any determinate figure; tin-stone.
It resembles a garnet of a blackish-brown colour, but is a great deal heavier; and has been considered, at the English tin-mines, as a stone containing no metal, until some years ago it began to be melted to great advantage.
n. Crystalized; tin-grains.
Is like the garnets, of a spherical polygonal polygonal figure, but looks more uncultuous on the surface.
1. In larger grains; and, 2. In smaller grains.
2. Mixed with the calx of iron. 3. Mixed with the manganese. 4. Mineralised with sulphur and iron; black lead.
V. Lead; Plumbum, Saturnus. It is,
a. Of a blueish-white colour when fresh broke, but soon dulls or fullies in the air. b. Is very heavy; viz. to water as 11,325 to 1000. c. Is softer next to gold; but has no great tenacity, and is not in the least fonoorous. d. It is easily calcined; and, by a certain art in managing the degrees of the fire, its calx becomes white, yellow, and red. e. This calx melts easier than any other metallic calx to a glass, which becomes of a yellow colour, and semi-transparent. This glass brings other bodies, and the imperfect metals, into fusion with it. f. It dissolves, 1st, In the spirit of nitre; 2dly, In a diluted oil of vitriol, by way of digestion; 3dly, In the vegetable acid; 4thly, In alkaline solutions; and 5thly, In expressed oils, both in the form of metal and of calx; g. It gives a sweet taste to all solutions. h. It amalgamates with quicksilver. i. With the spirit of sea-salt it has the same effect as silver, whereby is produced a saturnus corrosive. k. It does not unite with iron, when it is alone added to it in the fire. l. It works on the cupel, which signifies that its glass enters into certain porous bodies, destitute of phlogiston and alkaline salts. m. It melts in the fire before it is made red-hot, almost as easily as the tin. n. Its calx or glass may be reduced to its metallic state by pot-ashes.
Lead is found,
A. In form of a calx.
(1.) Pure. a. Friable; lead ochre; native cerus. This is found at Kristersberget in Westmanland in Sweden, on the surface of the potter's ore. b. Indurated; lead spar, or spatole lead ore. 1. Radiated, or fibrous. a. White. 2. Crystallised into a prismatical figure. a. White. b. Yellowish green.
(2.) Mixed. a. With the calx of arsenic; arsenic lead-spar. 1. Indurated. a. White. Mr Cronstedt has tried such an ore from an unknown place in Germany, and found that no metallic lead could be melted from it by means of the blow-pipe, as can be done out of other lead spars; but it must be performed in a crucible, and then that part of the arsenic which did not fly off in smoke during the experiment was likewise reduced, and found in form of grains dispersed, and forced into the lead. Another ore of this kind, which likewise was not easily reduced by means of the blow-pipe, did always, after being melted, and during the cooling, hastily shoot into polygonal, but mostly hexagonal crystals, with shining surfaces. Can this crystallisation be owing to salts, which are said not to act in this manner but when they are dissolved in water?
B. Mineralised.
1. With sulphur alone: the bley-schweif, or bley-glanz, of the Germans. a. Steel-grained lead-ore; from the mines at Hellefors, in the province of Westmanland. b. Radiated, or antimoniated lead-ore. c. Teffellated, or potter's lead-ore.
At Villach in Austria there is said to be found a potter's lead-ore, which contains not the least portion of silver.
2. With sulphurated silver. Galena; also called bleyglanz, by the Germans. a. Steel-grained. b. With small scales; is found at Selberg, and is there particularly called blyschweif. c. Fine-grained. d. Of a fine cubical texture; and, e. Of coarse cubes. These two varieties are found in all the Swedish silver-mines.
f. Crystallised.
The steel-grained and scaly ores are of a dim and dull appearance when they are broke, and their particles have no determined angular figure: they are therefore in Swedish commonly called blyschweif; in opposition to the cubical ores, which are called blyglanz. The most part of the ores called blyglanz contain silver, even to 24 ounces per cent, of which we have instances in the mines of Salberg, where it has been observed, that the coarse cubical lead ores are generally the richest in silver, contrary to what what is commonly taught in books; the reason of which may perhaps be, that, in making the essays on these two ores, the coarse cubical can be chosen purer or freer from the rock than the fine cubical ores.
3. With sulphurated iron and silver. This is found, a. Fine-grained. b. Fine cubical. c. Coarse cubical. When this ore is scorched, it yields a black flag; whereas the preceding lead-ores yield a yellow one, because they do not contain any iron.
4. With sulphurated antimony and silver; antimonated or radiated lead-ore. This has the colour of a blyglanz, but is of a radiated texture.
It is found, a. Of fine rays and fibres; and, b. Of coarse rays or fibres. The lead in this ore prevents any use being made of the antimony to advantage; and the antimony likewise in a great measure hinders the extracting of the silver.
VI. Copper; Cuprum, Venus, &c.
This metal is, a. Of a red colour. b. The specific gravity of the Japan copper is 9000, and of the Swedish 8784 or 8843 to 1000. c. It is pretty soft and tough. d. The calx of copper being dissolved by acids becomes green, and by alkalies blue. e. It is easily calcined in the fire into a blackish blue substance, which, when rubbed to a fine powder, is red; when melted together with glass, it tinges it first reddish brown, and afterwards of a transparent green or sea-green colour. f. It dissolves in all the acids; viz. the acids of vitriol, sea-salt, nitre, and the vegetable; and likewise in all alkaline solutions. That it becomes rusty, and tarnishes in the air (a consequence of a former solution), depends very much on some vitriolic acid which is left in the copper in the refining of it. This metal is easier dissolved when in form of a calx than in a metallic state, especially by the acids of vitriol and sea-salt, and the vegetable acid. g. Vitriol of copper is of a deep blue colour; but the vegetable acid produces with the copper a green salt, which is verdigrise. h. It can be precipitated out of the solutions in a metallic state; and this is the origin of the precipitated copper of the mines, called Ziment copper. i. It is not easily amalgamated with quicksilver; but requires for this purpose a very strong trituration, or the admixture of the acid of nitre. k. It becomes yellow when mixed with zinc, which has a strong attraction to it, and makes brats, pinchbeck, &c. l. It is easily dissolved by lead glass, which last is coloured green by it. m. When this metal is exposed to the fire, it gives a green colour to the flame in the moment it begins to melt, and continues to do so afterwards, without losing anything considerable of its weight. n. It requires a strong degree of heat before it melts, yet is it a lesser degree than for iron.
Copper is found in the earth,
A. Native, or in a metallic state; virgin or native copper. 1. Solid, is found in the iron mine of Hefslakulla in the province of Nerieke, and at Sunnerskog in the province of Smoland; also in the Russian Karelia, and in other foreign places. 2. Friable, in form of small, and somewhat coherent grains. Precipitated or ziment copper. It is found at Riddarhyttan in Westmanland, at Falun in Dalarna, and in Hungary.
It has been observed, that both copper and silver glass ore, being precipitated from water, become friable and granulated, but that they in time grow solid and ductile: whence the dispute about the distinction between native and precipitated copper may cease; the rather as native copper will scarcely be found in other places, and in any other kinds of stones, than those thro' which the ziment or vitriolic waters have circulated; although the fissures through which it has run may afterwards be filled with a stony substance.
B. In form of a calx.
(1.) Pure. A. Loose or friable; Ochra veneris. 1. Blue; Cæruleum montanum. Is very seldom found perfectly free from a calcareous substance. 2. Green; Viride montanum. Both these colours depend on menstrua, which often are edulcorated or washed away. 3. Red. This is an efflorescence of the glass copper ore. It is found in the province of Dal, and at Ostanberg in the province of Dalarna.
B. Indurated. Glass copper ore. a. Red. This is sometimes as red as sealing wax, and sometimes of a more liver-brown colour. It is found in Sandbacken, at Norberg in Westmanland, at Ordal in Norway, in Siberia, and in Swabia in Germany.
This ore is always found along with native copper, and seems to have lost its phlogiston by way of efflorescence, and to be changed into this form. It is likewise found along with the sulphurated copper; and is commonly, though very improperly, called glass copper ore.
(2.) Mixed. A. Loose or friable; Ochra veneris friabilis impura. 1. Mixed with a calcareous substance; Cæruleum montanum. In this state copper blue is mostly found. It ferments during the solution in aquafortis. 2. Mixed with iron. Black. It is the decom- decomposition of the Fahlun copper ore.
b. Indurated. 1. Mixed with gypsum, or plaster. Green. Is found at Ordal in Norway, and there called malachites. 2. Mixed with quartz. Red. From Sunner-skog, in the province of Smoland. 3. Mixed with lime. Blue. This is the lapis armenus, according to the accounts given of it by authors.
C. Dissolved and mineralised; Cuprum mineralisatum.
(1.) With sulphur alone. Grey copper ore. Is improperly also called glaas copper ore. a. Solid, without any certain texture. This is very soft, so that it can be cut with a knife, almost as easily as black lead. b. Fine-cubical; Minera cupri sulphurata tessilis confusa minoribus. Both these varieties are found at Sunnerskog in Smoland; where the last is sometimes found decomposed or weathered, and changed into a deep mountain blue.
(2.) With sulphurated iron. Minera cupri pyritacea; yellow copper ore. Marcaitical copper ore; Pyrites cupri. This is various both in regard to colour, and in regard to the different proportion of each of the contained metals; for instance, a. Blackish grey, inclining a little to yellow; Pyrites cupri griseus. When decayed or weathered, it is of a black colour; is the richest of all the varieties of this kind of copper ore, yielding between 50 and 60 per cent. and is found in Spain and Germany. b. Reddish yellow, or liver brown, with a blue coat on the surface; Minera cupri lazurea. This ore yields between 40 and 50 per cent. of copper, and is commonly said to be blue, though it is as red, when fresh broke, as a red copper regulus. c. Yellowish green; Pyrites cupri flavo viridescentes. This is the most common in the north part of Europe; and is, in regard to its texture, found, 1. Solid, and of a shining texture, from Oltanberg in the province of Dalarn. 2. Steel-grained, of a dim texture, from the same place, and Falun in Dalarn. 3. Coarse-grained, is of an uneven and shining texture. It occurs in most of the Swedish and Norwegian copper mines. 4. Crystallised marcasitical copper ore. a. Of long octahedral crystals. This is found at Hevafjord in the province of Dal, and in Lovilagruva in Westmanland; notwithstanding its existence is denied by Henckel and his followers. d. Pale-yellow. This cannot be described but as a marcasite, though an experienced eye will easily discover some difference between them. It yields 22 per cent. of copper.
e. Liver-coloured. This is found at Falon, in Darlarne in Sweden, where it contains copper; though at most other places where it occurs, it does not contain any copper, but is only a martial marcasite.
(3.) With sulphurated arsenic and iron. White copper ore. It is said to be found in the Hartz in Germany, and to resemble an arsenical pyrites; but most of the pyritical copper ores, as well as the marcasites, contain a little arsenic, though it is in too small a quantity to be observable.
(4.) Dissolved by the vitriolic acid; Vitriolum venetum.
(5.) With phlogiston. Copper coal-ore.
VII. Iron; Ferrum, Mars. It is, a. Of a blackish blue shining colour. b. It becomes ductile by repeated heating between coals, and hammering. c. It is attracted by the lodestone, which is an iron ore; and the metal itself may also be rendered magnetic. d. Its specific gravity to water is as 7,645, or 8000 : 1000. e. It calcines easily to a black scaly calx, which, when pounded, is of a deep red colour. f. When this calx is melted in great quantity with glass compositions, it gives a blackish brown colour to the glass; but in a small quantity a greenish colour, which at last vanishes, if forced by a strong degree of heat. g. It is dissolved by all salts, by water, and likewise by their vapours. The calx of iron is dissolved by the spirit of sea-salt, and by aqua regia. h. The calx of the dissolved metal becomes yellow, or yellowish brown; and in a certain degree of heat, it turns red. i. The same calx, when precipitated from acids by means of the fixed alkali, is of a greenish colour; but it becomes blue, when precipitated by means of an alkali united with phlogiston; in which last circumstance the phlogiston unites with the iron: these two precipitates lose their colour in the fire, and turn brown. k. The vitriol of iron is brown. l. It is the most common metal in nature, and at the same time the most useful in common life; notwithstanding which, its qualities are perhaps very little known.
Iron is found,
A. In form of calx. [1.] Pure. a. Loose and friable. Martial ochre; Alnora ochracea. 1. Powdery; Ochra ferris. This is commonly yellow or red, and is iron which has been dissolved by the vitriolic acid. 2. Concreted. Bog-ore. a. In form of round porous balls. b. More solid balls. c. In small flat pieces, like cakes, or pieces of money.
Vol. VII.
Class IV.
a. In small grains. b. Indurated. The bloodstone; Hematites. (1.) Of an iron colour; Hematites coruscans. This is of a blueish grey colour; it is not attracted by the loadstone, yields a red powder when rubbed, and is hard. a. Solid, and of a dim appearance when broken. b. Cubical, and of a shining appearance when broken. c. Fibrous, is the most common torsten of Sweden. d. Scaly; the eisenman of the Germans. 1. Black; from Gellebeck, in Norway. 2. Blueish grey; from Reka Klitt. When this is found along with marcasite, as at Sandfwar in Norway, it is not only attracted by the loadstone, but is of itself really a loadstone. c. Crystallised. 1. In octohedral crystals. 2. In polyhedral crystals. 3. In a cellular form. These varieties are the most common in Sweden, and are very seldom blended with marcasite, or any other heterogeneous substance, except their different beds. It is remarkable, that, when these ores are found along with marcasite, those particles which have lain nearest to the marcasite are attracted by the loadstone, although they yield a red, or reddish brown powder, like those which are not attracted by the loadstone: it is likewise worth observation, that they generally contain a little sulphur, if they are imbedded in a lime-stone rock, which, however, very seldom happens in Sweden; but there is one such instance at Billsta in Soderberke, in the province of Dalarne.
(2.) Blackish brown bloodstone; Hematites nigrescens. Kidney ore. This yields a red or brown powder when it is rubbed; it is very hard, and is attracted by the loadstone. a. Solid, with a glassy texture. b. Radiated. c. Crystallised. 1. In form of cones, from Siberia. 2. In form of concentric balls, with a faceted surface. These are very common in Germany, but very scarce in Sweden.
(3.) Red bloodstone; Hematites ruber. Red kidney ore.
a. Solid, and dim in its texture. b. Scaly. The eisenman of the Germans. This is commonly found along with the iron-coloured iron glimmer, and smears the hands. c. Crystallised, in concentric balls, with a flat or faceted surface.
(4.) Yellow bloodstone; Hematites flavus. a. Solid. b. Fibrous, from Lamerhof in Bohemia. The varieties of the colours in the bloodstone are the same with those produced in the calces of iron, made by dry or liquid menstrua, and afterwards exposed to different degrees of heat.
[2.] Iron in form of calx, mixed with heterogeneous substances. A. With a calcareous earth. White spathose iron ore. The stabelflein of the Germans. B. With a siliceous earth. The martial jasper of Sinople. C. With a garnet earth. Garnet and cockle or shirl. D. With an argillaceous earth. The bole. E. With a micaeous earth. Mica. F. With manganese. G. With an alkali and phlogiston. Blue martial earth. Native Prussian-like blue. 1. Loofe or powdery; found among the turf in the levels of the province of Skone; also in Sax Weissenfels, and at Norvlanden in Norway, &c. H. With an unknown earth, which hardens in water. Tarras; Cementum. 1. Loofe or granulated; Terra Puzzolana: from Naples and Civita Vecchia in Italy. This is of a reddish brown colour, is rich in iron, and is pretty fusible. 2. Indurated; Cementuminduratun. This is of a whitish yellow colour, contains likewise a great deal of iron, and has the same quality with the former, to harden soon in water, when mixed with mortar. This quality cannot be owing to the iron alone, but rather to some particular modification of it occasioned by some accidental causes, because these varieties rarely happen at any other places except where volcanos have been, or are yet in the neighbourhood.
I. Calx of iron, united with another unknown earth. The tungsten of the Swedes. This is also, though improperly, called white tin-grains. This resembles the garnet-stone, and the tin-grains; is nearly as heavy as pure tin; very refractory in the fire, and excessively difficult to reduce to metal. Iron has, however, been melted out of it to more than 30 per cent. It is very difficultly dissolved by borax and alkaline salts, but melts very easily with the microcosmic salt; giving a black slag; and for this reason, this last mentioned salt must be employed in the experiments on this stone. It is found,
1. Solid and fine-grained. a. Reddish or flesh-coloured. b. Yellow.
2. Spathose, and with an unctuous surface. a. White. b. Pearl-coloured. This kind of stone is very seldom met with, but in such places where black-lead is common in the neighbourhood; and the history of the black lead, inserted in the Memoirs of the Swedish Academy of Sciences, gives reason to believe, that this may contain some tin; which merits further examination.
Mr Cronstedt has in the said Memoirs communicated his experiments upon this kind of stone from Riddarhyttan, and Bipsberg in Westmanland; as has also Mr Rinman, on a great number of other martial earths. See the Memoirs for the years 1751 and 1754.
B. Dissolved or mineralised iron.
[1.] With sulphur alone. a. Perfectly saturated with sulphur; Ferrum sulphure saturatum. Marcasite. b. With very little sulphur. Black iron ore. Iron stone.
This is either attracted by the loadstone, or is a loadstone itself attracting iron; it resembles iron, and yields a black powder when rubbed.
(1.) Magnetic iron ore. The loadstone, Magnes. a. Steel-grained, of a dim texture, from Hogberget in the parish of Gagnef in Dalarne: it is found at that place almost to the day, and is of as great strength as any natural loadstones were ever commonly found. b. Fine grained, from Saxony. c. Coarse-grained, from Spetallgrufvan at Norberg, and Kiergrufvan, both in the province of Westmanland. This loses very soon its magnetic virtue. d. With coarse scales, found at Sandvær in Norway. This yields a red powder when rubbed.
(2.) Refractory iron ore. This in its crude state is attracted by the loadstone. a. Giving a black powder when rubbed; Tritura atra. Of this kind are, 1. Steel-grained. 2. Fine-grained. 3. Coarse-grained. This kind is found in great quantities in all the Swedish iron mines; and of this most part of the fusible ores consist, because it is commonly found in such kinds of rocks as are very fusible: and it is as seldom met with in quartz as the haematites is met with in limestone.
b. Rubbing into a red powder. These are real haematites, that are so far modified by sulphur or lime as to be attracted by the loadstone. 1. Steel-grained. 2. Fine-grained. Emery. This is imported from the Levant: it is mixed with mica, is strongly attracted by the loadstone, and smells of sulphur when put to the fire. 3. Of large shining cubes. 4. Coarse, scaly. The ejenglimmer or eisenman, from Gellebeck in Norway.
These are very scarce in Sweden, most part of the Swedish bloodstones being pure, as has already been said, and form that very profitable ore in Swedish called torrfsten.
[2.] With arsenic; Ferrum arsenico mineralisatum. Called milspickel by the Germans, and plate mundic in Cornwall.
[3.] With sulphurated arsenic. Arsenical pyrites.
[4.] With vitriolic acid. Martial vitriol.
[5.] With phlogiston. Martial coal ore.
[6.] With other sulphurated and arsenicated metals. See these in their respective arrangements.
Second Order. Semi-metals.
There are but seven semi-metals yet discovered, viz.
I. Quicksilver, mercury; Argentum vivum, mercurius, hydrargyrum.
This distinguishes itself from all metals, by the following qualities: a. Its colour is white and shining, a little darker than that of silver. b. It is fluid in the cold, and divisible by the least force; but as it only sticks to a few bodies, to which it has an attraction, it is said that it does not wet. c. It is volatile in the fire. d. Its weight is next to that of the gold, viz. to water, as 13,1593 : : 1000. e. It attracts the other semi-metals and metals, and unites with them all, except cobalt and nickel, with which it cannot by any means yet known be made to mix. This union is called an amalgamation. This amalgamation, or mixture of metallic bodies, according to the readiness with which they unite or mix, is in the following progression, viz. gold, silver, lead, tin, zinc, bismuth, copper, iron, and the regulus of antimony: but the three latter, however, do not very readily amalgamate. The iron requires a solution of the vitriol of iron, as a medium to promote the union. f. It dissolves in the spirit of nitre, out of which it is precipitated by a volatile alkali, and the common salt, in form of a white powder; but if a fixed alkali is used, into a yellow powder or calx.
g. It dissolves in the oil of vitriol by a strong boiling.
h. It is not affected by the acid of common salt, unless it be previously dissolved by other acids; in which case only they unite with one another, and may be sublimed together, which sublimation is a strong poison.
i. It unites with sulphur by grinding; and then produces a black powder called *ethiops mineralis*, which sublimes into a red striated body called *fusitious cinnabar*.
k. The sulphur is again separated from the quicksilver, by adding iron or lime, to which the sulphur attaches itself, leaving the quicksilver to be distilled over in a metallic form; but if a fixed alkali is added to it, some part of the quicksilver will remain in the residuum, and in that case makes a liver of sulphur.
Quicksilver is found,
A. Native, or in a metallic state. This is found in the quicksilver mines at Idria in Friuli, or the Lower Austria, in clay, or in a black flaky lapis ollaris, out of which it runs, either spontaneously or by being warmed even in the hands. It has several times been found at Herr Sten's Bottn, in the mines of Salberg in Westmanland, and sometimes also amalgamated with native silver.
B. Mineralised,
(1.) With sulphur. Cinnabar; *Cinnabaris nativa*. This is of a red colour, and its specific gravity to water is as 7500 to 1000.
a. Loose or friable cinnabar; looks like red ochre.
b. Indurated. Solid cinnabar. Is of a deep red colour; and, with respect to its texture, is either,
1. Steel-grained: 2. Radiated:
3. Composed of small cubes, or scaly:
4. Crystallised, a. In a cubical form; it is transparent, and deep red as a ruby.
(2.) With sulphur and copper; *Mercurius cupro sulphurato mineralisatus*. This is blackish grey, of a glassy texture, and brittle; crackles and splits excessively in the fire; and when the quicksilver and sulphur are evaporated, the copper is discovered by its common opaque red colour in the glas of borax, which, when farther forced in the fire, or diluted, becomes green and transparent.
II. Bismuth; tin-glas. *Vifmutum, bismutum, marcapita officinalis*. It is,
a. Of a whitish yellow colour.
b. Of a laminated texture, soft under the hammer, and nevertheless very brittle.
c. Its specific gravity to water is, as 9700 : 1000.
d. It is very fusible; calcines and scorifies like lead, if not rather earlier; and therefore it works on the cuppel. It is pretty volatile in the fire.
e. Its glas or flag becomes yellowish brown, and has the quality of retaining some part of the gold, if that metal has been melted, calcined, and vitrified with it.
f. It may be mixed with the other metals, except cobalt and zinc, making them white and brittle.
g. It dissolves in aquafortis, without imparting to it any colour; but to the aqua-regia it gives a red colour, and may be precipitated out of both these solutions with pure water, into a white powder, which is called *Spanisch white*. It is also precipitated by the acid of sea-salt; which last unites with it, and makes the *vifmutum cornicum*.
h. It amalgamates easily with quicksilver. Other metals are so far attenuated by the bismuth, when mixed with it, as to be strained or forced along with the quicksilver through skins or leather.
Bismuth is found in the earth.
A. Native. This resembles a regulus of bismuth, but consists of smaller scales or plates.
1. Superficial, or in crusts.
2. Solid, and composed of small cubes. This is found in and with the cobalt ore, at Schneeberg in Saxony, and other foreign places; likewise along with the copper ore, at Nyberget, in the parish of Stora Skedwi, in the province of Dalarne.
B. In form of calx.
1. Powdery or friable; *Ochra vifmuti*. This is of a whitish yellow colour; it is found in form of an efflorescence, to the day, at Los in the province of Helsingland.
It has been customary to give the name of flowers of bismuth to the pale red calx of cobalt, but it is wrong; because neither the calx of bismuth, nor its solutions, become red, this being a quality belonging to the cobalt.
C. Mineralised bismuth. This is, with respect to colour and appearance, like the coarse tessellated potter's lead ore; but it consists of very thin square plates or flakes, from which it receives a radiated appearance when broken crosswise.
1. With sulphur.
a. With large plates or flakes, from Bastnas at Riddarhyttan, Bafringe and Stripas in Westmanland.
b. With fine or small scales, from Jacobsgruvan at Riddarhyttan, and the mines at Los in the parish of Farila in Helsingland.
2. With sulphurated iron.
a. Of coarse, wedge-like scales, from Kongruben, at Gellebeck in Norway.
This mineralised bismuth ore yields a fine radiated regulus; for which reason it has been ranked among the antimonial ores, by those who have not taken proper care to melt a pure regulus or destitute of sulphur from it; while others, who make no difference between regulus and pure metals, have still more positively asserted it to be only an antimonial ore.
III. Zinc; spelter. *Zincum*.
a. Its colour comes nearest to that of lead, but it does not so easily tarnish.
b. It shows a texture, when it is broken, as if it were compounded of flat pyramids. c. Its specific gravity to water is, as 6,900 or 7,000 to 1,000.
d. It melts in the fire before it has acquired a glowing heat; but when it has gained that degree of heat, it burns with a flame of a changeable colour, between blue and yellow; and if in an open fire, the calx rises in form of soft white flowers; but if in a covered vessel, with the addition of some inflammable, it is distilled in a metallic form; in which operation, however, part of it is sometimes found vitrified.
e. It unites with all the metals, except bismuth, and makes them volatile. It is, however, not easy to unite it with iron without the addition of sulphur. It has the strongest attraction to gold and copper, and this last metal acquires a yellow colour by it; which has occasioned many experiments to be made to produce new metallic compositions.
f. It is dissolved by all the acids: of these the vitriolic acid has the strongest attraction to it; yet it does not dissolve it, if it is not previously diluted with much water. The abundance of phlogiston in this semi-metal is perhaps the reason of its strong attraction to the vitriolic acid.
g. Quicksilver amalgamates easier with zinc than with copper, by which means it is separated from compositions made with copper.
h. It seems to become electrical by friction, and then its smaller particles are attracted by the loadstone; which effects are not yet perfectly investigated; but they may excite philosophers to make farther experiments, in order to discover whether the electrical power shews itself in the metals by being attracted by the loadstone, or whether the magnetic power can be exerted on other metals than iron.
Zinc is found,
A. In form of calx.
(1.) Pure. a. Indurated. i. Solid. ii. Crystallised. This is of a whitish grey colour, and its external appearance is like that of a lead spar; it cannot be described, but is easily known by an experienced eye. It looks very like an artificial glass of zinc; and is found among other calamines at Namur, and in England.
(2.) Mixed. a. With a martial ochre; Ochra five calx zinci martialis. i. Half indurated. Calamine; Lapis calcinarius. a. Whitish yellow, b. Reddish brown. This seems to be a mouldered or weathered blende.
b. With a martial clay or bole. c. With a lead ochre and iron.
B. Mineralised zinc.
(1.) With sulphurated iron. Blende, mock-lead, black-jack, mock-ore; pseudogalena and blende of the Germans.
A. Mineralised zinc in a metallic form. Zinc ore.
This is of a metallic blueish grey colour, neither perfectly clear as a potter's ore, nor so dark as the Swedish iron ores.
1. Of a fine cubical or scaly texture. 2. Steel-grained.
B. In form of calx. Blende. Mock-lead; Sterile nigrum. Pseudogalena. This is found,
1. With coarse scales, a. Yellow; semi-transparent. b. Greenish. c. Black; pitchblende or pitch blende of the Germans. d. Blackish brown.
2. With fine scales, a. White. b. Whitish yellow. c. Reddish brown.
3. Fine and sparkling; at Goslar called braun bleiertz. a. Dark brown.
The zinc, in these last kinds of blends, is as it were in form of a calx or glass, so that they are often transparent: on the contrary, in the zinc ore, (no 261,) it seems rather to be in a metallic form, or, like most other metals, mineralised with sulphur. The sulphur, nevertheless, exists in the different kinds of blende, equally as in the zinc ore; and this remarkable difference in their appearance must be accounted for from another principle than the quantity of the zinc which they contain; because the yellow and white blends are often found richer than the zinc ores; but the zinc ores are, however, more easy to melt, and consequently more profitable. Perhaps it is because the blende does not contain a sufficient quantity of the phlogiston of the sulphur, to prevent the calcination of the zinc.
It is no matter whether a calcined blende is called calamine or not, provided it has such properties that it may be employed to the same purpose, and with the same advantage, as that calamine which nature has freed from its sulphur by its weathering or decaying. This may be done with some kinds of blende; and Mr Von Swab has given evident and excellent proofs of it in Sweden; in somuch that it would demonstrate a want of experience to insist that sulphur cannot be expelled by calcination, without destroying the zinc itself, and that flowers of zinc may be produced from zinc ores in a calcining heat, without addition of any phlogiston. Mr Justi however avers, that he has found an ore of this quality, which in his Mineralogy he calls Zinkspat; but there is great reason to doubt if it really contains any zinc, until it is proved whether the author added any phlogiston during the calcination, or reduced the zinc out of it; because, although the flowers of zinc may not always be perfectly well calcined, yet there is no instance of a natural zinc ore being discovered, which by itself yields those flowers during the calcination: and it requires, besides, a strong heat to produce these flowers from a perfect calx or glass of this semi-metal, either natural or artificial, though mixed with a phlogiston; for it could not have been a native zinc, since it resembled a spar, and such a one very likely is not to be found in nature.
IV. Antimony; Antimonium Stibium. This semi-metal is,
a. Of a white colour almost like silver. b. Brittle; and in regard to its texture, it consists of shining planes, of greater length than breadth. c. In the fire it is volatile, and volatilizes part of the other metals along with it, except gold and platinum. It may, however, in a moderate fire, be calcined into a light grey calx, which is pretty refractory in the fire, but melts at last to a glass of a reddish brown colour. d. It dissolves in spirit of sea-salt and aqua regia, but is only corroded by the spirit of nitre into a white calx; it is precipitated out of the aqua regia by water. e. It has an emetic quality when its calx, glass, or metal, is dissolved in an acid, except when in the spirit of nitre, which has not this effect. f. It amalgamates with quicksilver, if the regulus, when fused, is put to it; but the quicksilver ought for this purpose to be covered with warm water: it amalgamates with it likewise, if the regulus of antimony be previously melted with an addition of lime.
Antimony is found in the earth.
A. Native.
This is of a silver colour, and its texture is composed of pretty large shining planes.
This kind was found in Carls Ort, in the mine of Salberg, about the end of the last century; and specimens thereof have been preserved in collections under the name of an arsenical pyrites, until the mine-master Mr Von Swab discovered its real nature, in a treatise he communicated to the Royal Academy of Sciences at Stockholm in the year 1748. Among other remarkable observations in this treatise, it is said, first, That this native antimony easily amalgamated with quicksilver; doubtless, because it was imbedded in a lime-stone; since, according to Mr Pott's experiments, an artificial regulus of antimony may, by means of lime, be disposed to an amalgamation: Secondly, That when brought in form of a calx, it shot into crystals during the cooling.
B. Mineralised antimony.
(1.) With sulphur.
This is commonly of a radiated texture, composed of long wedge-like flakes or plates; it is nearly of a lead colour, and rough to the touch.
a. Of coarse fibres. b. Of small fibres. c. Steel-grained, from Saxony and Hungary. d. Crystallised, from Hungary.
1. Of a prismatical, or of a pointed pyramidal figure, in which last circumstance the points are concentrical.
Mr Cronstedt mentions a specimen of this, in which the crystals were covered with very minute crystals of quartz, except at the extremities, where there was always a little hole: this specimen was given for a floes ferris spar.
(2.) With sulphur and arsenic. Red antimony ore; Antimonium folare.
This is of a red colour, and has the same texture with the preceding, though its fibres are not so coarse.
a. With small fibres. b. With abrupt broken fibres, from Braunsdorf in Saxony, and from Hungary.
All antimonial ores are somewhat arsenical, but this is more so than the preceding kinds.
(3.) With sulphurated silver. Plumose silver-ore.
(4.) With sulphurated silver, copper, and arsenic.
(5.) With sulphurated lead.
V. Arsenic. This is,
a. In its metallic form, nearly of the same colour as lead, but brittle, and changes sooner its shining colour in the air, first to yellow, and afterwards to black. b. It appears laminated in its fractures, or where broken. c. Is very volatile in the fire, burns with a small flame, and gives a very disagreeable smell like garlic. d. It is, by reason of its volatility, very difficult to be reduced, unless it is mixed with other metals: However, a regulus may be got from the white arsenic, if it is quickly melted with equal parts of pot-ashes and soap; but this regulus contains generally some cobalt, most of the white arsenic being produced from the cobalt ores during their calcination. The white arsenic, mixed with a phlogiston, sublimes likewise into octahedral crystals of a metallic appearance, whose specific gravity is 8.308. e. The calx of arsenic, which always, on account of of its volatility, must be got as a sublimation, is white, and easily melts to a glaas, whose specific gravity is 5,000. When sulphur is blended in this calx, it becomes of a yellow, orange, or red colour; and according to the degrees of colour is called orpiment or yellow arsenic; sandarach, realgar, or red arsenic; and also rubinus arsenici.
f. This calx and glaas are dissoluble in water, and in all liquids; though not in all with the same facility. In this circumstance arsenic resembles the salts; for which reason it also might be ranked in that class.
g. The regulus of arsenic dissolves in spirit of nitre; but as it is very difficult to have it perfectly free from other metals, it is yet very little examined in various menstrua.
h. It is poisonous, especially in form of a pure calx or glaas: But probably it is less dangerous when mixed with sulphur, since it is proved by experience, that the men at mineral works are not so much affected by the smoke of this mixture as by the smoke of lead; and that some certain nations make use of the red arsenic in small doses as a medicine.
i. It unites with all metals, and is likewise much used by nature itself to dissolve, or, as we term it, to mineralise, the metals, to which its volatility and dissolubility in water must greatly contribute. It is likewise most generally mixed with sulphur.
k. It absorbs or expels the phlogiston, which has coloured glasses, if mixed with them in the fire.
Arsenic is found,
[1.] Native; called Scherbencobalt and Fliegenstein by the Germans.
It is of a lead colour when fresh broken, and may be cut with a knife, like black lead, but soon blackens in the air. It burns with a small flame, and goes off in smoke.
A. Solid and testaceous.
This is found in the mines of Saxony, the Hartz, and Hungary.
B. Scaly, at Kongberg in Norway.
C. Friable and porous; Fliegenstein.
(1.) With shining fissures.
This is by some called Spigel cobalt, (minera cobalti specularis), according to their notions of the affinity of these metals to one another. However, there always remains after the volatilisation of the scherbencobalt, some calx, either of cobalt or bismuth, and some silver, though in too small a quantity to deserve any notice.
(2.) In form of a calx.
A. Pure, or free from heterogeneous substances.
1. Loose or powdery. 2. Indurated, or hardened. This is found in form of white semi-transparent crystals.
B. Mixed with sulphur.
1. Hardened. a. Yellow. Orpiment; Auripigmentum. b. Red. Native realgar, or sandarach.
The orpiment may perhaps be found naturally in loose scaly powder, as it is sometimes met with in the shops; however, the hardened fort is seldom found but in collections.
C. Mixed with the calx of tin, in the tin-grains.
D. With sulphur and silver, in the rothgulden, or red silver ore.
E. With calx of lead, in the lead-spar.
F. With calx of cobalt, in the efflorescence of cobalt.
[2.] Mineralised.
A. With sulphur and iron. Arsenical pyrites or marcasite. These kinds in Cornwall are called silvery or white mundics, and plate mundics.
This alone produces red arsenic, when calcined, and is found in great quantities in the mines of Loras in the province of Dalarne: It is of a deeper colour than the following.
B. With iron only. This differs with regard to its particles, being,
1. Steel-grained; 2. Coarse-grained, from Westerfjellverberget; 3. Crystallised.
a. In an octahedral figure. This is the most common kind.
b. Prismatical. The sulphureous marcasite is added to this kind, when red arsenic is to be made; but in Sweden it is scarcer than the sulphureous arsenical pyrites.
C. With cobalt, almost in all cobalt ores.
D. With silver.
E. With copper.
F. With antimony.
VI. Cobalt.
This semi-metal is,
a. Of a whitish grey colour, nearly as fine-tempered steel.
b. Is hard and brittle, and of a fine-grained texture; hence it is of a dulky, or not shining appearance.
c. Its specific gravity to water is 6000 to 1000.
d. Is first in the fire, and becomes black by calcination; it then gives to glasses a blue colour, inclining a little to violet, which colour, of all others, is the most fixed in fire.
e. The concentrated oil of vitriol, aquafortis, and aqua-regia, dissolve it; and the solutions become red. The cobalt calx is likewise dissolved by the same menstrua, and also by the volatile alkali and the spirit of sea-fall.
f. When united with the calx of arsenic in a flow (not a brisk) calcining heat, it assumes a red colour: the same colour is naturally produced by way of efflorescence, and is then called the bloom, or flowers of cobalt. When cobalt and arsenic are melted together in an open fire, they produce a blue flame.
g. It does not amalgamate with quicksilver by any means hitherto known.
h. Nor does it mix with bismuth, when melted with it, without addition of some medium to promote their union.
The cobalt is most commonly found in the earth mixed with iron. A. In form of a calx.
(1.) With iron without arsenic. a. Loose or friable. Cobalt ochre. It is black, and like the artificial zaffre. b. Indurated; the schlacken or flag cobalt. This is likewise of a black colour, but of a glassy texture; and seems to have lost that substance which mineralised it, by being decayed or weathered. It is often confounded with the scherbencobalt, for it is seldom quite free from arsenic; and there may perhaps exist a progressive series from the schlacken kind to the scherbencobalt kind.
(2.) With the calx of arsenic. Cobalt-blut; Ochra cobalti rubra; bloom, flowers, or efflorescence, of cobalt. a. Loose or friable. This is often found of a red colour like other earths, spread very thin on the cobalt ores, and is, when of a pale colour, erroneously called flowers of bismuth. b. Indurated. Hardened flowers of cobalt. This is commonly crystallised in form of deep red semi-transparent rays or radiations.
A white cobalt-earth, or ochre, is said to have been found. It has been seen and examined by a celebrated mineralist, who has found it in every respect, except the colour, to resemble the cobalt flowers; and it is very possible that those cobalt flowers might in length of time have lost their red colour, and become white.
B. Mineralised.
(1.) With arsenic and iron in a metallic form. This is of a dim colour when broken, and not unlike steel. It is found, a. Steel-grained. b. Fine-grained. c. Coarse-grained. d. Crystallised. 1. In a dendritical or arborescent form. 2. Polyédral, with shining surfaces; the glanzkoholt of the Germans. 3. In radiated nodules.
(2.) With sulphurated iron. This is of a lighter colour than the preceding, nearly like to tin or silver. It is found, a. Crystallised. 1. In a polygonal form. a. Of a flaky texture. b. Coarse-grained. This kind discovers not the least mark of arsenic. The coarse-grained becomes flaky in the fire, and sticks to the stirring hook during the calcination, in the same manner as many regulus do; and is a kind of regulus prepared by nature.
That sort of a flaky texture is very martial, and is described by the mine-master Mr Brandt, in the Acts of the Swedish Academy of Sciences for the year 1746. Both these give a beautiful colour.
(3.) With sulphur, arsenic, and iron. This resembles the arsenicated cobalt ore, being only rather of a whiter or lighter colour. It is found, a. Coarse-grained. b. Crystallised. 1. In a polygonal figure, with shining surfaces, or glanzkoholt. It is partly of a white or light colour, and partly of a somewhat reddish yellow.
(4.) With sulphurated and arsenicated nickel and iron; see no 279.
VII. Nickel; Niccolum. This is the latest discovered semi-metal. It was first described by its discoverer Mr Cronstedt, in the Acts of the Royal Academy of Sciences at Stockholm for the years 1751 and 1754, where it is said to have the following qualities: That,
1. It is of a white colour, which, however, inclines somewhat to red. 2. Of a solid texture, and shining in its fractures. 3. Its specific gravity to water is as 8,500 to 1000. 4. It is pretty fixed in the fire; but, together with the sulphur and arsenic, with which its ore abounds, it is so far volatile as to rise in form of hairs and branches, if in the calcination it is left without being stirred. 5. It calcines to a green calx. 6. This calx is not very fusible, but, however, tinged glass of a transparent reddish-brown or jacinth colour. 7. It dissolves in aquafortis, aqua regia, and the spirit of sea-salt, but more difficulty in the vitriolic acid, tinging all these solutions of a deep green colour. Its vitriol is of the same colour; but the colcothar of this vitriol, as well as the precipitates from the solutions, become by calcination of a light green colour. 8. These precipitates are dissolved by the spirit of sal ammoniac, and the solution has a blue colour; but being evaporated, and the sediment reduced, there is no copper, but a nickel regulus is produced. 9. It has a strong attraction to sulphur; so that when its calx is mixed with it, and put on a scorifying test under the mussel, it forms with the sulphur a regulus: this regulus resembles the yellow steel-grained copper-ores, and is hard and shining on its convex surface. 10. It unites with all the metals, except quicksilver and silver. When the nickel regulus is melted with the latter, it only adheres close to it, both the metals lying near one another on the same plane; but they are easily separated with a hammer. Cobalt has the strongest attraction to nickel, after that to iron, and then to arsenic. The two former cannot be separated from one another but by their scorification; which is easily done, since
11. This semi-metal retains its pilogiston a long time in the fire, and its calx is reduced by the help of a very small portion of inflammable matter: it requires, however, a red heat before it can be brought into fusion, and melts a little sooner, or almost as soon as copper or gold, consequently sooner than iron. The nickel is found.
A. In form of a calx. Nickel ochre.
1. Mixed with the calx of iron. This is green, and is found in form of flowers on Kupfer-nickel.
B. Mineralised nickel.
1. With sulphurated and arsenicated iron and cobalt. Kupfernickel. This is of a reddish yellow colour; and is found,
a. Of a flaggy texture, in Saxony.
b. Fine-grained; and
c. Scaly, in Loos cobalt-mines in the province of Helsingeland, at which place it is of a lighter colour than the foreign ones. These two are often from their colour confounded with the liver-coloured marcasite.
2. With the acid of vitriol. This is of a beautiful green colour, and may be extracted out of the nickel ochre, or efflorescence of the Kupfernickel.
Of Saxa and Petrifications.
Though the Saxa, and fossils commonly called petrifications, cannot be ranked in a mineral system, as consisting of principles already taken notice of; yet as these bodies, especially the latter, occupy so considerable a place in most mineral collections, and the former must necessarily be taken notice of by the miners in the observations they make in the subterranean geography, it appeared proper to subjoin them in such an order as may answer the purpose for which they are regarded by miners and mineralogists.
First Order.
SAXA. Petrae.
These may be divided into two kinds.
1. Compound saxa, are stones whose particles, consisting of different substances, are so exactly fitted and joined together, that no empty space, or even cement, can be perceived between them; which seems to indicate, that some, if not all, of these substances have been soft at the instant of their union.
2. Conglutinated stones, are stones whose particles have been united by some cementitious substance, which, however, is seldom perceivable, and which often has not been sufficient to fill every space between the particles: in this case the particles seem to have been hard, worn off, and in loose, single, unfigured pieces, before they were united.
I. Compound saxa.
A. Ophites. Scaly limestone with kernels or bits of serpentine stone in it.
1. Kolmord's marble. It is white and green.
2. Serpentino antico, is white, with round pieces of black fleatites in it. This must not be confounded with the serpentino verde antico.
3. The Haraldsio marble. White, with quadrangular pieces of a black fleatites.
4. The marmor pozzevera di Genova. Dark green marble, with white veins. This kind receives its fine polish and appearance from the serpentine stone.
B. Stellsten or gestellstein; Saxum compositum par-
Vol. VII. not perfectly free from cross veins of quartz, which always are in the surface of the rock, and spoil the whetstones. It is also said to be found in Tellemarken in Norway. The best of this sort come from the Levant, and are pretty dear. The whetstone kinds, when they split easily, and in thin plates, are very fit to cover houses with, tho' most of them are not used for that purpose.
E. The tegsten of the Swedes. Lapis allaris. Saxum compositum jaspite et mica. a. Light grey. b. Whitish yellow. c. Dark grey. d. Dark green. This is employed with great advantage to build fire-places and furnaces, &c. and when it is flaty, the extremities of the strata must be turned towards the fire.
F. Porphyry; Porphyrites. Italorum porfido. Saxum compositum jaspide et feltspato, interdum mica et bafalite. a. Its colour is green, with light green feltspat, Serpentino verde antico. It is said to have been brought from Egypt to Rome, from which latter place the specimens of it now come. b. Deep red, with white feltspat. c. Black, with white and red feltspat. d. Reddish brown, with light-red and white feltspat. e. Dark grey, with white grains of feltspat also. Many varieties of this kind in regard to colour are found in form of nodules or loose stones in Sweden; but we have only mentioned the hardest and finest of those which are found in the rocks; because, besides these, there are coarse porphyries found, which scarce admit of any polish. The dark red porphyry has been most employed for ornaments in building; yet it is not the only one known by the name of porfido, the Italians applying the same name also to the black kind.
G. The trapp of the Swedes. Saxum compositum jaspide martiali mollis, seu argillae martiali indu-ralis, et. This kind of stone sometimes constitutes or forms whole mountains; as, for example, the mountain called Hummelberg in the province of Västergötland, and at Drammen in Norway; but it is oftenest found in form of veins in mountains of another kind, running commonly in a serpentine manner, contrary or across to the direction of the rock itself. It is not homogeneous, as may be plainly seen at those places where it is not pressed close together; but where it is pressed close, it seems to be perfectly free from heterogeneous substances. When this kind is very coarse, it is interspersed with feltspat; but it is not known if the finer sorts likewise contain any of it. Besides this, there are also some fibrous particles in it, and something that resembles a calcareous spar; this, however, does not ferment with acids, but melts as easy as the stone itself, which becomes a black solid glass in the fire. By calcination it becomes red, and yields in essays 12 or more per cent. of iron. No other sort of ore is to be found in it, unless now and then somewhat merely superficial lies in its fissures; for this stone is commonly, even to a great depth in the rock, cracked in acute angles, or in form of large rhomboidal dice. It is employed at the glass-houses, and added to the composition of which bottles are made. By the Germans it is called schwach or schwartsstein; at the Swedish glass-works, trappskoel, tegellskoel, or svartskoel; and at Jarlsberg in Norway, blabælt. In the air it decays a little, leaving a powder of a brown colour; it cracks commonly in the fire, and becomes reddish brown if made red-hot. It is found, 1. Of coarse chaffy particles. a. Dark grey. b. Black. 2. Coarse-grained. a. Dark grey. b. Reddish. c. Deep brown. 3. Of fine imperceptible particles. a. Black. The touchstone; Lapis lydius. b. Blueish. c. Grey. d. Reddish.
The black variety (3.a.) is sometimes found so compact and hard, as to take a polish like the black agate; it melts, however, in the fire to a black glass; and is, when calcined, attracted by the loadstone.
H. Amygdaloides. Saxum basi jaspide martiali, cum fragmentis spati calcarei et serpentinis, figu-rat elliptica. The carpolithi or fruit-stone rocks of the Germans. It is a martial jasper, in which elliptical kernels of calcareous spar and serpentine stone are included. a. Red, with kernels of white limestone, and of a green steatites. This is of a particular appearance, and when calcined is attracted by the loadstone; it decays pretty much in the air, and has some affinity with the trapp, and also with the porphyry. There are sometimes found pieces of native copper in this stone.
I. The gronsten of the Swedes. Saxum compositum micae et hornblende. Its basis is hornblende, intermixed with mica. It is of a dark green colour, and is dug in several places in Smoland, where it is employed in the iron furnaces as a flux to the bog ore.
K. The granites. Saxum compositum feltspato, micae et quartzoe, quibus accidentaliter interdum hornblende, fleatite, granatæ et bafalites immix-ti sunt. Its principal constituent parts are feltspat, or rhombic quartz, mica, and quartz.
It is found, (1.) Loose or friable. This is used at the Swedish brass-works to cast the brass in, and comes from France. (2.) Hard and compact.
Saxa.
Saxa.
Congluti- nated Stones.
a. Red. 1. Fine-grained. 2. Coarse-grained.
b. Grey, with many and various colours. The granites are seldom flatly or laminated, when their texture is close, and the harder particles, as the felt-spat or rhombic quartz, the quartz, and the flint, predominate in it. They admit of a good polish; for which reason the Egyptians in former times, and the Italians now, work them into large pieces of ornamental architecture; for which purpose they are extremely fit, as they do not decay in the air.
II. Conglutinated saxa.
A. Of larger or broken pieces of stones of the same kinds conglutinated together. Breccia.
1. Of limestone cemented by lime. a. The calcareous breccia; Breccia calcarea: the marmi brecciati of the Italians.
When these kinds have fine colours, they are polished and employed for ornaments in architecture, and other economical uses: they come from Italy.
b. The lumachella of the Italians, or shell-marbles. These are a compound of shells and corals, which are petrified or changed into lime, and conglutinated with a calcareous substance. When they have many colours, they are called marbles, and employed for the same purposes as the preceding.
2. Of kernels of jasper cemented by a jaspery substance. Breccia jaspidea. Diafragm brecciato of the Italians. Of this kind specimens from Italy are seen in collections. A coarse jasper breccia is said to be found not far from Frejus in Provence in France.
3. Of siliceous pebbles, cemented by a jaspery substance, or something like it. The plum-pudding stone of the English. Breccia silicea. Its basis, which at the same time is the cement, is yellow, wherein are contained single flinty or agaty pebbles, of a grey colour or variegated. This is of a very elegant appearance when cut and polished; it is found in England.
4. Of quartzose kernels combined with an unknown cement. Breccia quartzosa.
5. Of kernels of several different kinds of stones. Breccia saxosa. a. Of kernels of porphyry, cemented by a porphyry or coarse jaspery substance; Breccia porphyrea. b. Of kernels of several saxa; Breccia indeterminata. Is found in loose stones in Dalarne, and are originally broken from the Fiell tracts in Serna, which consist of nothing else but conglutinated stones. c. Of conglutinated kernels of sandstone; Breccia arenacea. This kind consists of sandstone kernels, which have been combined a second time together.
The above-mentioned brecciae of themselves must demand the distinctions here made between, but which perhaps may seem to be carried too far, since their particles are so big and plain as to be easily known from one another. These stones are a proof both of the subversions which the mountains in many centuries have undergone, and of some of hidden means which nature makes use of in thus cementing different kinds of stones together. Any certain signs for the kernels or lumps in such compounds, before they deserve the name of breccia, cannot be determined, because that depends on a comparison which every one is at liberty to imagine.
At one place in the mountain called Hekkerget, the kernels of porphyry have a diameter of six feet, while in other places they are no bigger than walnuts. At Maffewala, the kernels have a progressive size down to that of a fine sandstone. Most of this kind of stone is fit for ornaments, though the workmanship is very difficult and costly.
B. Conglutinated stones of grannies or sands of different kinds. Sandstone; Lapis arenaceus.
In this division are reckoned those which consist of such minute particles, that all of them cannot easily be discovered by the naked eye. The greatest part, however, consist of quartz and mica; which substances are the most fit to be granulated, without being brought to a powder.
1. Cemented by clay. a. With an argyrous or refractory clay; is of a loose texture, but hardens, and is very refractory in the fire. b. With common clay; from Burswick in the island of Gotland.
2. With lime; resembles mortar made with coarse sand. a. Consisting of transparent and greenish grains of quartz and white limestone. b. Of no visible particles. This is of a loose texture, and hardens in the air.
3. With an unknown cement. a. Loose. b. Harder. c. Compact. d. Very hard.
4. Cemented by the rust or ochre of iron. Is found in form of loose stones at several places, and ought perhaps to be reckoned among the minerae arenaceae or sand-ores; at least when the martial ochre makes any considerable portion of the whole.
C. Stones and ores cemented together; Minerae arenaceae.
1. Of larger fragments. a. Mountain green, or viride montanum cupri, and pebbles cemented together, from Siberia. b. Potters lead-ore, with limestone. c. Yellow or marcasitical copper ore, with small pebbles.
2. Of smaller pieces. a. Potters lead-ore with a quartzose fand. b. Mountain green with fand from Siberia. c. Cobalt ore with fand. d. Martial ochre with fand.
SECOND ORDER.
MINERAL CHANGES, or the PETRIFICATIONS.
Mineralia-Larvata, vulgo Petrifacta,
Are mineral bodies in the form of animals or vegetables, and for this reason no others belong to this order than such as have been really changed from the subjects of the other two kingdoms of nature. There is more difficulty to determine the first point, viz. from when these bodies are to be styled petrifications, than from when they cease to be such.
I. Earthy changes; Terre larvata. Terrificata.
A. Extraneous bodies changed into a lime substance, or calcareous changes; Larvae calcarea.
1. Loose or friable. Chalky changes; Crete larvata.
a. In form of vegetables. b. In form of animals.
1. Calcined or mouldered shells; Humus conchaceus.
2. Indurated; Petrifica calcarea.
a. Changed and filled with solid lime-stone. 1. In form of animals. 2. In form of vegetables.
b. Changed into a calcareous spar; Petrifica calcarea spatoa.
1. In form of animals. 2. In form of vegetables.
B. Extraneous bodies changed into a flinty substance. Siliceous changes; Larvae silicea. These are like the flint,
1. Indurated.
a. Changed into flints.
1. Carnelians in form of shells, from the river Tomm in Siberia. 2. Agat in form of wood. Such a piece is said to be in the collection of Count Teflin. 3. Coraloids of white flint, (Millepora). 4. Wood of yellow flint.
C. Extraneous bodies changed into clay. Argillaceous changes; Larvae argillacea.
A. Loose and friable.
1. Of porcelain clay. a. In form of vegetables.
A piece of white porcelain clay from Japan, with all the marks of the root of a tree, has been observed in a certain collection.
2. Indurated.
1. In an unknown clay. a. In form of vegetables.
Osteocolla. It is said to be changed roots of the poplar tree, and not to consist of any calcareous substance.
A fort of fossil ivory is said to be found, which has the properties of a clay; but it is doubtful if it is rightly examined.
II. Saline extraneous bodies, or such as are penetrated by mineral salts. Corpora peregrina insalita. Metallic changes, Larvae insalite.
A. With the vitriol of iron.
1. Animals.
a. Human bodies have been twice found in the mine at Falun in Dalarna; the last was kept a good many years in a glass-case, but began at last to moulder and fall to pieces.
2. Vegetables.
a. Turf, and b. Roots of trees.
These are found in water strongly impregnated with vitriol. They do not burn with a flame, but only like a coal in a strong fire; neither do they decay in the air.
III. Extraneous bodies penetrated by mineral inflammable substances, or mineral phlogiston.
A. Penetrated by the substance of pit-coals.
1. Vegetables, which commonly have been woods, or appertaining to them.
a. Fully saturated. Gagai. Jet.
The jet is of a solid shining texture.
b. Not perfectly saturated; Alumia vegetabilis. Is loose; resembles umbre, and may be used as such.
B. Penetrated by rock-oil or asphaltum.
1. Vegetables.
a. Turf.
The Egyptian mummies cannot have any place here, since art alone is the occasion that those human bodies have in length of time been penetrated by the asphaltum, in the same manner as has happened naturally to the wood in pit-coal strata.
C. Penetrated by sulphur which has dissolved iron, or by marcasite and pyrites; Pyrite impregnata. Petrifica pyritacea.
1. Human.
a. Bivalves, b. Univalves, c. Insects.
IV. Metals in form of extraneous bodies; Larvae metallicifera.
A. Silver; Larvae argentifera.
1. Native.
a. On the surfaces of shells.
2. Mineralised with copper and sulphur.
a. Fahlertz, or grey silver ore in form of ears of corn, &c. and supposed to be vegetables, are found in argillaceous slate at Frankenberg and Tahlitteren in Hesse.
B. Copper; Larvae cuprifera.
1. Copper in form of calx.
a. In form of animals, or of parts belonging to them.
1. Ivory, and other bones of the elephant.
The Turcois or Turkey stone. It is of a blueish-green colour, and much valued in the east.
At Simore in Languedoc bones of animals are dug, which during the calcination assume a blue colour; but it is not not probable that the blue colour is owing to copper.
(2.) Mineralised copper, which impregnates extraneous bodies; Caprum mineralisatum corpora peregrina ingressum.
A. With sulphur and iron. The yellow or marcasitical copper-ore that impregnates,
1. Animals. a. Shells. b. In form of fish.
B. With sulphur and silver. Grey silver-ore or sahlerls, like ears of corn, from the slate-quarries in Hesse.
C. Changes into iron; Larva ferriferae.
(1.) Iron in form of calx, which has assumed the place or the shape of extraneous bodies; Ferrum calciforme corpora peregrina ingressum.
a. Loofe; Larvae ochraceae.
1. Of vegetables.
Roots of trees, from the lake Langelma in Finland. See the acts of the Swedish Academy of Sciences for the year 1742.
b. Indurated; Larvae hematiticae.
1. Of vegetables.
(2.) Iron mineralised, assuming the shape of extraneous bodies.
a. Mineralised with sulphur. Marcasite. Larvae pyritaceae.
V. Extraneous bodies decomposing, or in a way of destruction; Corpora peregrina in gradibus destructionis considerata. Mould; Humus; Turf; Turba.
A. From animals. Animal-mould; Humus animalis.
1. Shells. Humus conchaceus.
2. Mould of other animals; Humus diversorum animalium.
B. Vegetable mould; Humus vegetabilis.
1. Turf; Turba.
a. Solid, and hardening in the air; Turba solidia aëre indurescens.—Is the best of this kind to be used for fuel, and comes nearest to the pit-coals. It often contains a little of the vitriolic acid.
b. Lamellated turba; Turba foliata. This is in the first degree of destruction.
2. Mould of lakes; Humus lacustris. This is a black mould which is edulcorated by water.
3. Black mould; Humus ater.
This is universally known, and covers the surface of that loose earth in which vegetables thrive best.
THIRD ORDER. NATURAL SLAGS.
Scoria Vulcanorum.
SLAGS are found in great abundance in many places in the world, not only where volcanoes yet exist, but likewise where no subterraneous fire is now known:
Yet, in Mr Cronstedt's opinion, they cannot be produced but by means of fire. These are not properly to be called natural, since they have marks of violence, and of the last change that mineral bodies can suffer without the destruction of the world; nor are they artificial, according to the universally-received meaning of this word. When we, perhaps, in future times, by new-discovered means, may be able to find out of what sort of earth stones are compounded, we shall still be forced to stop at the surface of them, and be contented with knowing that they contain a little iron.
A. Iceland agate; Achates islandicus niger.
It is black, solid, and of a glassy texture; but in thin pieces it is greenish and semi-transparent like glass-bottles, which contain much iron. The most remarkable is, that such large solid masses are found of it, that there is no possibility of producing the like in any glass-house.
It is found in Iceland, and in the island of Ascension: The jewellers employ it as an agate, though it is too soft to resist wear.
B. Rhenish millstone; Lapis molaris Rhenanus.
Is blackish-grey, porous, and perfectly resembles a sort of flag produced by mount Vesuvius.
C. Pumice-stone; Pumex.
Is very porous and blistered, in consequence of which it is specifically very light. It resembles that frothy flag which is produced in our iron furnaces.
1. White. 2. Black.
The colour of the first is perhaps faded or bleached, because the second kind comes in that state from the laboratory itself, viz, the volcanoes.
D. Pearl flag; Scoria conflantes globulis vitreis conglomeratis.
Is compounded of white and greenish glass particles, which seem to have been conglomerated while yet soft, or in fusion. Found on the isle of Ascension.
E. Slag-sand or ashes; Scoria pulverulentæ cineres vulcanorum.
This is thrown out from volcanoes in form of larger or smaller grains. It may perhaps be the principle of the Terra Puzzolana, because such an earth is said at this time to cover the ruins of Herculaneum near Naples, which history informs us was destroyed by a volcano during an earthquake.