that quality of certain bodies which excites the sensation of smell. In the Annales de Chimie, Vol. XXI. p. 254, we have a detailed account of certain experiments made by M. Benedict Prevost of Geneva, with a view to render the emanations of odorant bodies perceptible to sight. The account is by much too long for a work like ours; especially as we feel not ourselves inclined to attribute to the experiments all the importance which seems to have been allowed to them by the first class of the French National Institute. We shall therefore state only a few of them, which seem most to favour the author's hypothesis.
1. A concrete odorant substance, laid upon a wet glass or broad saucer, covered with a thin stratum of water, immediately causes the water to recede, so as to form a space of several inches around it.
2. Fragments of concrete odorant matter, or small morsels of paper or cork, impregnated with an odorant liquor, and wiped, being placed on the surface of water, are immediately moved by a very swift rotation. Romieu had made this observation on camphor, and erroneously attributed the effect to electricity. The motion was perceptible even in pieces of camphor of seven or eight gros.
3. An odorant liquor being poured on the water, stops the motion till it is diffused by evaporation. Fixed oil arrests the motion for a much longer time, and until the pellicle it forms on the water is taken off.
4. When the surface of the water is cleaned by a leaf of metal, of paper, or of glass, plunged in and withdrawn successively until the pellicle is removed, the gyratory motion is renewed. If a piece of red wax or of taper be dipped in water, and the drops shaken off into a glass of water containing odorant bodies in motion, the movement will be stopped. The same effect is not produced by metal.
5. A morsel of camphor, plunged to the depth of three or four lines in water, without floating, excites a movement of trepidation in the surrounding water, which repels small bodies in its vicinity, and carries them again to the camphor by flarts. The author concludes, that an elastic fluid escapes from the odorant body in the manner of the fire of a fuse or the discharge of fire-arms.
6. When there is a certain proportion between the height of the water and that of the small fragment of camphor, the water is briskly driven off, returns again to the camphor, and again retires, as if by an explosion, the recoil of which often causes the camphor to make part of a revolution on its axis.
7. Camphor evaporates thirty or forty times more speedily when placed upon water, than when entirely surrounded with air.
8. Camphor, during the act of dissipation in the air, preserves its form and its opaque whiteness; upon water it is rounded, and becomes transparent as if it had undergone a kind of fusion. It may be inferred, that this arises from the acquired motion, which causes it to present a greater surface to the air.
9. When small pieces of camphor are plunged in water, the camphor becomes rounded and transparent, does not acquire any motion, and its dissipation is less perceptible than in the air. The concurrence of air and water is therefore necessary to disengage the fluid which is the cause of the motion and total dissipation of odorant bodies.
10. The motion of odorant bodies upon water decays and ceases spontaneously at the end of a certain time; because the water having then contracted a strong smell, the volatilization takes place in all the points of its surface; and the small mass being thus surrounded by the odorant fluid, which is no longer air, dissolves, as in the ordinary odorant fluids, without forming the gaseous jet which is the cause of the motion. The author compares the volatilization of the aromatic substance to a combustion excited by water.
M. Prevost hopes, that these, and other experiments which he explains, will contribute to the theory of odours, which so nearly resembles that of the gases. He does not flatter himself with having exhausted this subject, but considers his discoveries as the means of rendering odour perceptible by water, not only to the sight, but even to the touch, as are likewise the vibrations of sonorous bodies. Men deprived of the sense of smell, and even the blind, according to him, may in this manner distinguish odorant bodies from those which have no smell. "Perhaps (says he) this kind of odoroscope may, by improvement, become an odorimeter. The exceptions, such for example as that of the cerumen of the ears, which produces much effect on water without being perceptibly odorant, and that of the fingers when hot or moist, are merely apparent; for if our senses do not in these cases discover odour, those of animals more powerfully energetic, such as the dog, perceive and distinguish individuals by its peculiar character. The odoroscope may afford the information which is wanting respecting these effluvia. Thus it is that the fat of game, the smell of which is nearly to us imperceptible, is very much so to dogs, and exhibits sensible marks by the odoroscope."
Professor Venturi of Modena, who heard Prevost's memoir read in the National Institute, had himself made some experiments with camphor kept separately in the air, in the water, and at the surface of the water; whence he deduces, that the most active virtue for dissolving camphor resides at that part where both the air and the water touch the camphor at the same time. Hence he explains why, in like circumstances, camphor evaporates more quickly in a moist than in a dry air; and why the Hollanders use water in their process for subliming this substance.
It might be thought that the camphor was decomposed at the surface of the water; that the water might seize the acidifying part, which renders the camphor concrete; and that the volatile part is diffused in the atmosphere. The author rejects this notion. He thinks that water with camphor floating on its surface becomes charged with no more than a very small portion: 1. Because in these circumstances the water acquires the same taste and smell of camphor as it obtains when a small quantity of this substance is kept plunged in the same fluid. This water, by exposure to the air, loses the qualities with which it had been charged, and becomes insipid, and without smell. 2. Because when the water is saturated with all it can take up, the dissipation of the camphor continues at its surface as before. 3. Because the aerial emanations of camphor made at the surface of water do themselves crystallize into camphor.
Camphor at the surface of the water does nothing, therefore, but dissolve; and when dissolved at the ordinary temperature of the atmosphere, it is not at first in the state of vapour, as has been thought. It is simply a liquid which extends itself over the surface of water itself; and by this means coming into contact with a great surface of air, it is afterwards absorbed and evaporated. This is proved by the following facts: 1. The solution of camphor at the surface of water is more rapid in proportion to the extent of the surface. In narrow vessels, the section of the column would not be completed in ten days, even though the water might be extremely pure. 2. When the column of camphor has projecting parts, the liquid may be seen issuing by preference from certain points of the column, covering the surface of the water, and driving small floating bodies before it, in the same manner as floating bodies go and return in a basin into which the water of a canal enters with rapidity. 3. If a small piece of camphor, already wetted at one end, be brought near the edge of water contained in a broad saucer, and be made to touch the saucer itself, it deposits a visible liquor, which is oily; and by attaching itself to the saucer, destroys the adhesion between the vessel and the border of the water, so that the water retires on account of the affinity of aggregation, which not being opposed by the attraction of the saucer, causes the water to terminate in a round edge. If you remove the piece of camphor, the water will not return to its place until the oily fluid is evaporated. 4. In the same manner, when the column of camphor is half immersed in the water, the oily liquor which issues forth destroys the adhesion of the water to the column, and produces a small surrounding cavity. The solution stops, or is retarded for a moment, until the fluid, extending itself over the water, becomes evaporated; the water then returns to its place, and touches the same part of the camphor; the solution begins again, and in this manner the process is effected by alternations of contact and apparent repulsion.
Of these memoirs by Prevost and Venturi, the English reader will find accurate and full translations in the first volume of Nicholson's Philosophical Journal, together with some judicious observations on them by the editor, which we shall take the liberty to adopt. "The philosophical consideration of odorant bodies is somewhat obscured by the old method of generalizing, or referring the properties of bodies to some distinct principle or thing supposed capable of being separated from the body itself. Thus the odours of bodies have been supposed to depend on a substance imagined in a loose way to be common to all and separable from them. Hence the terms, principle of smell, spiritus rectus, and even in the modern nomenclature we find aroma. There does not in effect seem to be any more reason to infer the existence of a common principle of smell than of taste. The smell of ammonia is the action of that gas upon the organ of sense; and this odorant invisible matter is exhibited to the sight when combined with an acid gas. But in the same manner as ammonia emanates from water, and leaves most part of that fluid behind, so will the volatile parts of bodies be most eminently productive of this action; and very few, if any, natural bodies will be found which rise totally. The most striking circumstance in the effect is, that an act of such power should be attended with a loss by exhalation which is scarcely to be appreciated by weight, or in any other method during a short interval of time. But we know too little of nervous action, and of other phenomena of electricity, of galvanism (See Galvanism in this Supplement), or even of heat, which strongly affect the senses, but elude measurement by gravitation, that the difficulty of weighing the effluvia of odorant bodies becomes less astonishing."
ECONOMISTS, a sect of philosophers in France, who have made a great noise in Europe, and are generally believed to have been unfriendly to religion. The founder of this sect was a Dr. Duquesnai, who had so well inculcated himself into the favour of Louis XV., that the king used to call him his thinker. The sect was called economists, because the economy and order to be introduced into the finances, and other means of alleviating the distresses of the people, were perpetually in their mouths. The Abbé Barruel admits, that there may have been some few of them who directed their speculations to no other object; but he brings very sufficient proof that the great aim of the majority of the sect was to eradicate from the minds of the people all reverence for divine revelation.
"Duquesnai (says he) and his adepts had more especially undertaken to persuade their readers, that the country people, and mechanics in towns, were entirely destitute of that kind of instruction necessary for their professions; that men of this class, unable to acquire knowledge by reading, pined away in an ignorance equally fatal to themselves and to the state; that it was necessary to establish free schools, and particularly throughout the country, where children might be brought up to different trades, and instructed in the principles of agriculture. D'Alembert, and the Voltairean adepts, soon perceived the advantages they could reap from these establishments. In union with the economists, they presented various memorials to Louis XV., in which not only the temporal but even the spiritual advantages of such establishments for the people are strongly urged. The king, who really loved the people, embraced the project with warmth. He opened his mind on the subject to Mr Bertin, whom he honoured with his confidence, and had entrusted with his privy purse; and it was with great difficulty that this minister could convince him of the dangerous designs of the sect.
"Determined (says he) to give the king positive proof that the economists imposed upon him, I sought to gain the confidence of those pedlars who travel through the country, and expose their goods to sale in the villages, and at the gates of country seats. I suspected those in particular who dealt in books to be nothing less than the agents of philosophy with the good country folks. In my excursions into the country I fixed my attention above all on the latter. When they offered me a book to buy, I questioned them what might be the books they had? Probably catechisms or prayer-books? Few others are read in the villages? At these words I have seen many smile. No, they answered, those are not our works; we make much more money of Voltaire, Diderot, and other philosophic writings. What! said I; the country people buy Voltaire and Diderot? Where do they find the money for such dear works? Their constant answer was, we have them at a much cheaper rate than prayer-books; we can sell them at ten sols (5 d.) a volume, and have a pretty profit in the bargain. Questioning some of them still farther, many of them owned that those books cost them nothing; that they received whole bales of them without knowing whence they came, but being simply desired to sell them in their journeys at the lowest price."
"Louis XV. warned by the discovery made by his minister, was at length satisfied that the establishment of these schools, so much urged by the conspirators, would only be a new instrument of seduction in their hands. He abandoned the plan; but, perpetually harassed by the protecting sophisters, he did not strike at the root of the evil, and but feebly impeded its progress. The pedlars continued to promote the measures of the conspirators; yet this was but one of the inferior means employed to supply the want of their free schools, as a new discovery brought to light one far more fatal.
"About the middle of the month of September 1789, little more than a fortnight antecedent to the atrocious 5th and 6th of October, at a time when the conduct of the National Assembly, having thrown the people into all the horrors of a revolution, indicated that they would set no bounds to their pretensions, Mr Le Roy, lieutenant of the King's Hunt, and an academician, being at dinner at the house of Mr D'Angerville, intendant of the buildings of his majesty, the..." conversation turned on the disasters of the revolution, and on those that were too clearly to be foreseen. Dinner over, the nobleman above-mentioned, a friend of Le Roy, hurt at having seen him so great an admirer of the philosophers, reproached him with it in the following expressive words: *Well! this, then, is the work of Philosophy! Thunderstruck at these words—Alas! cried the academician, to whom do you say so? I know it but too well, and I shall die of grief and remorse! At the word remorse, the same nobleman questioned him whether he had so greatly contributed towards the revolution as to upbraid himself with it in that violent manner?* Yes (answered he), I have contributed to it, and far more than I was aware of. I was secretary to the committee to which you are indebted for it; but I call heaven to witness, that I never thought it would go to such lengths. You have seen me in the king's service, and you know that I love his person. I little thought of bringing his subjects to this pitch, and I shall die of grief and remorse.*
"Prefixed to explain what he meant by this committee, this secret society, entirely new to the whole company, the academician resumed: *This society was a sort of club that we philosophers had formed among us, and only admitted into it persons on whom we could perfectly rely. Our fittings were regularly held at the Baron D'Holbach's. Left our object should be ruined, we called ourselves economists. We created Voltaire, though absent, our honorary and perpetual president. Our principal members were D'Alembert, Turgot, Condorcet, Diderot, La Harpe, and that Lamaron, keeper of the seals, who on his dismission shot himself in his park.*
"The whole of this declaration was accompanied with tears and sighs; when the adept, deeply penitent, continued: *The following were our occupations; the most of those works which have appeared for this long time past against religion, morals, and government, were ours, or those of authors devoted to us. They were all composed by the members or by the orders of the society. Before they were sent to the press, they were delivered in at our office. There we revised and corrected them; added to, or curtailed them, according as circumstances required. When our philosophy was too glaring for the times, or for the object of the work, we brought it to a lower tint; and when we thought that we might be more daring than the author, we spoke more openly. In a word, we made our writers say exactly what we pleased. Then the work was published under the title or name we had chosen, the better to hide the hand whence it came. Many, supposed to have been posthumous works, such as Christianity Unmasked, and divers others attributed to Ferret and Boulangier after their deaths, were issued from our society.*
"When we had approved of those works, we began by printing them on fine or ordinary paper, in sufficient number to pay our expenses, and then an immense number on the commonest paper. These latter we sent to hawkers and booksellers free of cost, or nearly so, who were to circulate them among the people at the lowest rate. These were the means used to pervert the people, and bring them to the state you now see them in. I shall not see them long, for I shall die of grief and remorse!*
"This recital is too well authenticated to be called in question, and too plain to need a commentary. Let it be a warning against all secret societies, by whatever title of benevolence they may be disguised by those who form them.
**Oil-mill**, a mill for expressing the oils from fruits, or grains, &c. As these kingdoms do not produce the olive, it would be needless to describe the mills which are employed in the southern parts of Europe. We shall content ourselves, therefore, with a description of a Dutch oil-mill, employed for grinding and pressing linseed, rape-seed, and other oleaginous grains. Further, to accommodate our description still more to our local circumstances, we shall employ water as the first mover; thus avoiding the enormous expense and complication of a windmill.
In Plate XXXVIII., fig. A,
1. Is the elevation of a wheel, over or undershot, as the situation may require.
2. The bell-metal socket, supported by masonry, for receiving the outer gudgeon of the water wheel.
3. The water course.
Fig. B.
1. A spur wheel upon the same axis, having 52 teeth.
2. The trundle that is driven by No. 1, and has 78 flaves.
3. The wallower, or axis for raising the pellets. It is furnished round its circumference with wipers for lifting the pellets, so that each may fall twice during one turn of the water wheel, that is, three wipers for each pellet.
4. A frame of timber, carrying a concave half cylinder of bell-metal, in which the wallower (casted in that part with iron plates) rests and turns round. It will be seen in profile, fig. G.
5. Masonry supporting the inner gudgeon of the water wheel and the above-mentioned frame.
6. Gudgeon of the wallower, which bears against a bell-metal step fixed in the wall. This double support of the wallower is found to be necessary in all mills which drive a number of heavy tampers.
Fig. C, Is the elevation of the kettle and press-frame, their furniture, the mortars, and the press-pellets.
1. The six pellets.
2. Cross pieces between the two rails of the frame, forming, with these rails, guides for the perpendicular motion of the pellets.
3. The two rails. The back one is not seen. They are checked and bolted into the standards No. 12.
4. The tails of the lift, corresponding to the wipers upon the wallower.
5. Another rail in front, for carrying the detents which hold up the pellets when not acting. It is marked 14 in fig. M.
6. A beam a little way behind the pellets. To this are fixed the pulleys for the ropes which lift and stop the pellets. It is represented by 16 in fig. M.
7. The said pulleys with their ropes.
8. The driver, which strikes the wedge that presses the oil.
9. The dishanger, a stamper which strikes upon the inverted wedge, and loosens the press. 10. The lower rail with its cross pieces, forming the lower guides of the pettles.
11. A small cog-wheel upon the wallower, for turning the spatule, which rises about the oil-feed in the chaffer-pan. It has 28 teeth, and is marked No. 6 in fig. M.
12. The four standards, mortised below into the block, and above into the joists and beams of the building.
13. The six mortars hollowed out of the block itself, and in shape pretty much like a kitchen pot.
14. The feet of the pettles, rounded into cylinders, and fitted with a great lump of iron.
15. A board behind the pettles, standing on its edge, but inclining a little backwards. There is such another in front, but not represented here. These form a sort of trough, which prevents the feed from being scattered about by the fall of the pettles, and loft.
16. The first press-box (also hollowed out of the block), in which the grain is squeezed, after it has come for the first time from below the millstones.
17. The second press-box, at the other end of the block, for squeezing the grain after it has passed a second time under the pettles.
18. Frame of timber for supporting the other end of the wallower, in the same manner as at No. 4, fig. D.
19. Small cog wheel on the end of the wallower for giving motion to the millstones. It has 28 teeth.
20. Gudgeon of the wallower, bearing on a bell metal socket fixed in the wall.
21. Vessels for receiving the oil from the press-boxes.
22. Joists supporting the block.
Fig. D. Elevation and mechanism of the millstones.
1. Upright shaft, carrying the great cog wheel above, and the runner millstone below in their frame.
2. Cog-wheel of 76 cogs, driven by No. 19. of fig. C.
3. The frame of the runners. This will be more distinctly understood in No. 4, fig. H.
4. The innermost runner, or the one nearest the shaft.
5. Outermost ditto, being farther from the shaft.
6. The inner rake, which collects the grain under the outer runner.
7. The outer rake, which collects the grain under the inner runner. In this manner the grain is always turned over and over, and crushed in every direction. The inner rake lays the grain in a slope, of which fig. O. is a section; the runner flattens it, and the second rake lifts it again, as is marked in fig. P; so that every side of a grain is presented to the millstone, and the rest of the lesser or nether millstone is so swept by them, that not a single grain is left on any part of it. The outer rake is also furnished with a rag of cloth, which rubs against the border or hoop that surrounds the nether millstone, so as to drag out the few grains which might otherwise remain in the corner.
8. The ends of the iron axle which passes through the upright shaft, and through the two runners. Thus they have two motions: 1st, A rotation round their own axis. 2nd, That by which they are carried round upon the nether millstone on which they roll. The holes in these millstones are made a little width, and the holes in the ears of the frame, which carry the ends of the iron axis, are made oval up and down. This great freedom of motion is necessary for the runner millstones, because frequently more or less of the grain is below them at a time, and they must therefore be at liberty to get over it without straining, and perhaps breaking, the shaft.
9. The ears of the frame which lead the two extremities of the iron axis. They are mortised into the under side of the bars of the square frame, that is carried round with the shaft.
10. The border or hoop which surrounds the nether millstone.
11. and 12. The nether millstone and masonry which supports it.
Fig. E. Form of the wallower, shewing the disposition of the wipers along its surface.
1. Two parts of this shaft, which are nicely rounded, and fortified with iron plates, and which rest upon the bell-metal concaves, which are represented in No. 4 of fig. C.
2. The little wheels at each end, for giving motion to the two spatules, marked No. 11, fig. C.
3. The wipers for the second press.
4. The wipers for the first press.
5. The wipers for the six pettles.
Fig. F. Represents the surface of the wallower unfolded into a rectangular parallelogram, in order to shew the distribution of the wipers, and consequently the succession of the strokes given by the different pettles. This distribution has something peculiar. Each pettle has three wipers; and there are also three for the driver and discharger of the second press. The driver and wiper of the first press have but one and a half; one for the driver, and the half for the discharger; so that it strikes twice, and the driver only once, in a turn of the shaft. This is the Dutch practice, which differs from that of Flanders. The succession of the strokes may be conceived as follows: Reckon the stampers, including those of the press, from the water wheel toward the other end of the wallower, and calling them a, b, c, d, e, f, g, h, i, k, and supposing that a makes the first stroke, they proceed in the following order for one turn of the wallower:
ab, df, b, c, e, g, ab, df, b, c, e, g.
Here it may be observed that a and b strike together. They would do so if allowed; but one of them is held up by its detent till the workman sees proper to disengage it. Each pettle, and the driver and discharger of the second press, makes three strokes for one turn of the wallower. But the driver k of the first press makes only one stroke in that time, namely, in the interval between the last stroke of e and g. The discharger i of this press makes two strokes; one of them in this same interval, and the other along with the first stroke of e. The second pressing requires a much more violent pressure than the first, because the cake must be left perfectly dry and hard.
Fig. G. Profile of the frame of timber which carries the wallower, and greatly contributes to render its motion steady.
Fig. H. Is a view of one of the millstones.
1. The nether millstones, and the masonry supporting the whole.
2. The runner. 3. A sort of case which encloses the two wings of the millstone at a very small distance from it, in order to prevent the grain which sticks to it from being scattered. There is another method practised at some mills.
Fig. I. Represents that of Sardamn. AA are two iron rods, about half an inch square, hanging on the axle, on each side of the millstone. These rods are joined by a cross piece C, which almost touches the millstone. A piece of leather is put between, which rubs upon the millstone, and clears it of the grain which chances to stick to it. No. 4. and 6. represent the ears of this frame, by which the end of the iron axle is supported, and carried round by the upright shaft n° 5.
Fig. K. Plan of the runner millstones, and the frame which carries them round.
1. Are the two millstones. 2. The outside pieces of the frame. 3. The cross bars of the frame which embrace the upright shaft 5, and give motion to the whole. 4. The iron axle upon which the runners turn. 5. The outer rake. 6. The inner ditto.
Fig. L. Represents the nether millstone seen from above.
1. The wooden gutter, which surrounds the nether millstone. 2. The border or hoop, about six inches high, all round, to prevent any feed from being scattered. 3. An opening or trap door in the gutter, which can be opened or shut at pleasure. When open, it allows the bruised grain, collected in and shoved along the gutter by the rakes, to pass through into troughs placed below to receive it. 4. Portion of the circle described by the outer runner. 5. Portion of the circle described by the inner one.
By these we see that the two stones have different routes round the axis, and bruise more feed.
6. The outer rake. 7. The inner ditto. 8. The sweep, making part of the inner rake, occasionally let down for sweeping off all the feed when it has been sufficiently bruised. The pressure and action of these rakes is adjusted by means of wooden springs, which cannot be easily and distinctly represented by any figure. The oblique position of the rakes (the outer point going foremost) causes them to shove the grain inwards or toward the centre, and at the same time to turn it over, somewhat in the same manner as the mould-board of a plough throws the earth to the right hand, and partly turns it over. Some mills have but one sweeper; and, indeed, there is great variety in the form and construction of this part of the machinery.
Fig. M. Profile of the pebble frame.
1. Section of the horizontal shaft. 2. Three wipers for lifting the pebbles. 3. Little wheel of 28 teeth for giving motion to the spatula. 4. Another wheel, which is driven by it, having 20 teeth. 5. Horizontal axle of ditto. 6. Another wheel on the same axle, having 13 teeth. 7. A wheel upon the upper end of the spindle, having 12 teeth. 8. Two guides, in which the spindle turns freely, and so that it can be shifted higher and lower.
9. A lever, moveable round the piece n° 14, and having a hole in it at 9, through which the spindle passes, turning freely. The spindle has in this place a shoulder, which rests on the border of the hole 9; so that by the motion of this lever the spindle may be disengaged from the wheel work at pleasure. This motion is given to it by means of the lever 10, 10, moveable round its middle. The workman employed at the chaffer pulls at the rope 10, 11, and thus disengages the spindle and spatula.
11. A pebble seen sidewise. 12. The lift of ditto. 13. The upper rails, marked n° 3. in fig. C. 14. The rail, marked n° 5. in fig. C. To this are fixed the detents, which serve to stop and hold up the pebbles. 15. A detent, which is moved by the rope at its outer end. 16. A bracket behind the pebbles, having a pulley, through which passes the rope going to the detent 15. 17. The said pulley. 18. The rope at the workman's hand, passing through the pulley 17, and fixed to the end of the detent 15.
This detent naturally hangs perpendicular by its own weight. When the workman wants to stop a pebble, he pulls at the rope 18, during the rise of the pebble. When this is at its greatest height, the detent is horizontal, and prevents the pebble from falling by means of a pin projecting from the side of the pebble, which rests upon the detent, the detent itself being held in that position by hitching the loop of the rope upon a pin at the workman's hand.
19. The two lower rails, marked n° 10. fig. C. 20. Great wooden, and sometimes stone, block, in which the mortars are formed, marked n° 21. in fig. C. 21. Vessel placed below the press boxes for receiving the oil. 22. Chauffer, or little furnace, for warming the bruised grain. 23. Basket in the front of the chauffer, tapering downwards, and opening below in a narrow slit. The hair bags in which the grain is to be pressed after it has been warmed in the chauffer, are filled by placing them in this basket. The grain is lifted out of the chauffer with a ladle, and put into these bags; and a good quantity of oil runs from it through the slit at the bottom into a vessel set to receive it.
24. The spatula attached to the lower end of the spindle, and turning round among the grain in the chauffer-pan, and thus preventing it from sticking to the bottom or sides, and getting too much heat.
Fig. N. Plan of part of the works.
1. Furnaces for warming the grain. 2. The baskets for holding the sacks while they are a-filling. 3. The pan in which the bruised grain is heated by the chauffer. 4. A trough for receiving the chips, into which the pressed oil-cakes are cut, to be afterwards put into the pan and warmed. 5. The press-box for the second pressing. 6. The press-box for the first pressing. 7. The fix mortars. 8. The sloping boards, to hinder the scattering of the oil seed. 9. The nether millstone, but out of its place. 10. Its centre a little higher than the rest. 11. A rib of wood going round the edge of the nether millstone, and even with its surface, but rising a very little outwards, and surrounded with a border or hoop about an inch high, to prevent the feed from being scattered on the ground.
Fig. Q. A section, lengthwise, of the great block, with the mortars and press-boxes. 1. The fix pellets. 2. The fix mortars, each of which has an iron plate at its bottom. 3. The driving flapper, which falls on the wedge of the first pressing. 4. Ditto, for the second ditto. 5. The dishanger, which strikes on the inverted wedge in order to free the press. 6. Ditto, for the second pressing. 7. Wedge for freeing the press. 8. Wedge for pressing. 9. Wooden cheeks, two inches thick, which are placed between the middle wedge and the sliding wedges on each side. 10. Press-irons, between which are placed the hair-bags containing the bruised grain. 11. Iron plate, called the fountain, at the bottom, pierced with holes, corresponding with a hole in the block, for allowing the oil to run off from the pressed grain. 12. Vessel for receiving ditto. 13. A long iron plate at the bottom of the press box, under the drawing and discharging wedges.
Fig. R. Another view of the press-irons. 1. The side-irons laid flat. 2. The same seen edgewise. 3. The pierced iron plate, upon which the two irons, no. 1. stand upright, with the hair-bag between them. 4. One of the hair-bags. It may be observed that the seams of these bags are made on the flat sides, and not on the edges, where they would be in danger of bursting. 5. A long hair-cloth, in which the bag is wrapped before it is set into the press. The bag, being filled with bruised grain, is placed with its bottom at a, and the top at b; the part ca is lapped over it, reaching to b, and then the other end d is lapped over that, and reaches to a, and the loop at its end serves as a handle by which to lift it, and place it properly between the press-irons.
Fig. S. The principal pieces of the press. 1. The wooden cheeks. 2. The discharging wedge. 3. The driving wedge. 4 and 5. The sliding blocks, which transmit the pressure produced by the driving wedge.
The foregoing enumeration and views of the different parts of a Dutch oil-mill, are sufficient, we imagine, to enable an intelligent mill-wright, to whom the machine is altogether new, to understand its manner of working, and its adaptation to the various parts of the process for extracting the oil from seeds or kernels. It would require a very minute description indeed to explain it to a person altogether unacquainted with mill-work.
The first part of the process is bruising the seed under the runner stones (a). That this may be more expeditiously done, one of the runners is set about ¼ of its own thickness nearer the shaft than the other. Thus they have different treads; and the grain, which is a little heaped towards the centre, is thus bruised by both. The inner rake gathers it up under the outer stone into a ridge, of which the section is represented in Plate XL fig. O. The stone passes over it and flattens it. It is gathered up again into a ridge, of the form of fig. P. under the inner stone, by the outer rake, which consists of two parts. The outer part presses close on the wooden border which surrounds the nether stone, and shoves the feed obliquely inwards, while the inner part of this rake gathers up what had spread toward the centre. The other rake has a joint near the middle of its length, by which the outer half of it can be raised from the nether stone, while the inner half continues pressing on it, and thus scrapes off the moist paste. When the feed is sufficiently bruised, the miller lets down the outer end of the rake. This immediately gathers the whole paste, and shoves it obliquely outwards to the wooden rim, where it is at last brought to a part that is left unboarded, and it falls through into troughs placed to receive it. These troughs have holes in the bottom, through which the oil drips all the time of the operation. This part of the oil is directed into a particular cistern, being considered as the purest of the whole, having been obtained, without prelude, by the mere breaking of the hull of the feed.
In some mills this operation is expedited, and a much greater quantity of this best oil is obtained, by having the bed of masonry which supports the lever formed into a little furnace, and gently heated. But the utmost care is necessary to prevent the heat from becoming considerable. This, enabling the oil to dissolve more of the fermentable substance of the feed, exposes the oil to the risk of growing soon very rancid; and, in general, it is thought a hazardous practice, and the oil does not bring to a high price.
When the paste comes from under the stones, it is put into the hair bags, and subjected to the first pressing. The oil thus obtained is also deemed as of the first quality, scarcely inferior to the former, and is kept apart (the great oil cistern being divided into several portions by partitions).
The oil cakes of this pressing are taken out of the bags, broken to pieces, and put into the mortars for the first flapping. Here the paste is again broken down, and the parenchyma of the feed reduced to a fine meal. Thus free grease is allowed to the oil from every vehicle in which it was contained. But it is now rendered much more clammy, by the forcible mixture of the musilage,
(a) We are told, that in a mill at Reichenhoffen in Alsace, a considerable improvement has been made by passing the feed between two small iron rollers, before it is put under the millstones. A great deal of work is said to be saved by this preliminary operation, and finer oil produced, which we think very probable. The flapping and pressing go on as in other mills. oil, and even of the finer parts of the meal. When sufficiently pounded, the workman stops the pestle of a mortar, when at the top of its lift, and carries the contents of the mortar to the first chafier pan; where it is heated to about the temperature of melting bees wax (this, we are told, is the test), and all the while stirred about by the spatula. From thence it is again put into hair bags, in the manner already described; and the oil which drips from it during this operation is considered as the best of the second quality, and in some mills is kept apart. The paste is now subjected to the second pressing, and the oil is that of the second quality.
All this operation of pounding and heating is performed by one workman, who has constant employment by taking the four mortars in succession. The putting into the bags and conducting of the pressing gives equal employment to another workman.
In the mills of Piccardy, Alfae, and most of Flanders, the operation ends here; and the produce from the chafier is increased, by putting a spoonful or two of water into the pan among the paste.
But the Dutch take more pains. They add no water to the paste of their first flambing. They say that this greatly lowers the quality of the oil. The cakes which result from this pressing, and are therefore sold as food for cattle, are still fat and softish. The Dutch break them down, and subject them to the pestles for the second flambing. These reduce them to an impalpable paste, stiff like clay. It is lifted out, and put into the second chafier pan; a few spoonfuls of water are added, and the whole kept for some time as hot as boiling water, and carefully stirred all the while. From thence it is lifted into the hair bags of the last press, subjected to the press; and a quantity of oil, of the lowest quality, is obtained, sufficient for giving a satisfactory profit to the miller. The cake is now perfectly dry, and hard, like a piece of board, and is sold to the farmers.
Nay, there are small mills in Holland, which have no other employment than extracting the oil from the cakes which they purchase from the French and Brandenburs; a clear indication of the superiority of the Dutch practice.
The nicety with which that industrious people conduct all their business is remarkable in this manufacture.
In their oil cisterns, the parenchymous part, which unavoidably gets through, in some degree, in every operation, gradually subsides, and the liquor, in any division of the cistern, comes to consist of strata of different degrees of purity. The pumps which lift it out of each division are in pairs; one takes it up from the very bottom, and the other only from half depth. The last only is barrelled up for the market, and the other goes into a deep and narrow cistern, where the dregs again subsides, and more pure oil of that quality is obtained. By such careful and judicious practices, the Dutch not only supply themselves with this important article, but annually send considerable quantities into the very provinces of France and Flanders where they bought the seed from which it was extracted. When we reflect on the high price of labour in Holland, on the want of timber for machinery, on the expense of building in that country, and on the enormous expense of windmill machinery, both in the first erection and the subsequent wear and tear, it must be evident, that oil mills erected in England on water falls, and after the Dutch manner, cannot fail of being a great national advantage. The chatellanie or seigneurie of Lille alone makes annually between 30,000 and 40,000 barrels, each containing about 26 gallons.
What is here delivered is only a sketch. Every person acquainted with machinery will understand the general movements and operations. But the intelligent mechanic well knows, that operations of this kind have many minute circumstances which cannot be described, and which, nevertheless, may have a great influence on the whole. The rakes in the bruising-mill have an office to perform which resembles that of the hand, directed by a careful eye and unceasing attention. Words cannot communicate a clear notion of this; and a mill, constructed from the best drawings, by the most skilful workman, may gather the seed to ill, that the half of it shall not be bruised after many rounds of the machinery. This produces a scanty return of the finest oil; and the mill gets a bad character. The proprietor loses his money, is discouraged, and gives up the work.—There is no security but by procuring a Dutch millwright, and paying him with the liberality of Britons. Such unhoped-for tasks have been performed of late years by machinery; and mechanical knowledge and invention is now so generally diffused, that it is highly probable that we should soon excel our teachers in this branch. But this very diffusion of knowledge, by encouraging speculation among the artists, makes it a still greater risk to erect a Dutch oil-mill without having a Dutchman, acquainted with its most improved present form, to conduct the work. We do our duty in giving this counsel.