(CHRISTIAN), an eminent German Philosopher and Essayist, was born on the 7th of January 1742, at Breslau, where his father exercised the trade of a dyer. He studied at the universities of Frankfort, Halle, and Leipsic; at which last place he obtained a professorship of philosophy, but was soon compelled to resign it, in consequence of bad health. He returned to his native town, where he continued to spend the remainder of his life in retirement. In his last years, he suffered much from a painful and incurable disease, which he endured with the most philosophical fortitude. He died at Breslau on the 1st of December 1798.

The character of Garve was exceedingly amiable, both as a man and a philosopher. His erudition was great; and his writings bear witness both to the extent of his knowledge, and the accuracy of his judgment. The celebrated Kant paid him the compliment of saying, that he was "a true philosopher, in the legitimate acceptation of the word."

Garve invented no system of his own, nor did he attach himself to the tenets of any one master. He belonged to that class of philosophers, who, without adopting any particular theory, take an impartial view of all systems of doctrine, and seek truth wherever it is to be found. The just and rational views which he inculcated on the subject of our moral and social duties, entitle him to the praise of a genuine practical philosopher. The history of philosophy is indebted to him for several new and ingenious illustrations; and he has left us a faithful though rapid sketch of the ancient and modern doctrines respecting the fundamental principles of moral philosophy. His literary essays display a refined taste, and a genius at once elegant and philosophical. His style is uniformly simple, perspicuous, and correct.

The principal works of Garve are, 1. Dissertatio de nonnullis que pertinent ad logicam probabilium, 1766, 4to. 2. Dissertatio de ratione scribendi historiam philosophicam. 3. A Prize Essay, in German, On the inclinations, which was crowned by the Royal Academy of Berlin, 1769, 4to. 4. Progr. legendorum philosophorum nonnulla et exemplum, 1770, 4to. 5. Remarks on the character and writings of Gellert, 1770, 8vo, in German. This treatise was translated into French, and inserted in the French translation of Gellert's works by Pajon. 6. A dissertation (in German) on the union of morals and politics, Breslau, 1788, 8vo; also translated into French. 7. Essays (in German) on various subjects in literature, morals, and social life. Of these, three volumes, we believe, were published during the author's life, and two have been added since his death. These volumes contain, among others, his Essays On society and solitude; On the existence of God; and his beautiful Treatise On patience, which he is said to have dictated on his death-bed. 8. A sketch (in German) of the most remarkable principles of moral philosophy, from the time of Aristotle to the present day; which was first prefixed to his translation of Aristotle's Ethics, and afterwards printed separately; Breslau, 1798, 8vo. 9. Some observations on the most general principles of morals, in German, Ibid. 1798, 8vo. Besides these works, Garve wrote a number of literary essays, which were inserted in various periodical publications. He also translated into German a variety of works, particularly from the English; many of which he enriched with valuable notes. Among these, we may notice the Ethics, Rhetoric, and Politics of Aristotle; Cicero's Offices; Burke On the Sublime and Beautiful; Smith's Wealth of Nations; Fergusson's Principles of Moral Philosophy; and Paley's Principles of Morals and Politics. Garve's Correspondence with Weisse, and some other friends, was published at Breslau, in 2 vols. 8vo.

See the Biographie Universelle, Tom. XVI. Art. Garve, by Degerando. GAS-LIGHTS.

Though the application of Gas-Lights to economical purposes is of recent date, a considerable time has elapsed since the public were, in some degree, made acquainted with the properties of the gas hitherto principally made use of for such purposes, and which is commonly known by the name of coal gas. The inflammable properties of gas, escaping from the surface of a spring in the neighbourhood of Wigan, in Lancashire, are described in the Philosophical Transactions for the year 1667; and in the volume for 1733, there is an account of the carbureted hydrogen, issuing from a coal-work in Cumberland, having been collected in a bladder, and burnt through a tube attached. In 1739, the Reverend John Clayton distilled coal in a close retort, and obtained therefrom a black oil, and a permanent gas (or spirit, as he calls it), and which latter he confined in bladders, and burned it through small orifices. There are other notices of burning wells and burning rocks, and of inflammable air having been found to arise from the distillation of coal, and of gases differently produced having been used for fire-works; but it does not appear that the idea of applying the light produced to useful purposes occurred to any person till the year 1792, when Mr William Murdock, of Soho, employed coal gas for the purpose of lighting his house and offices, then at Redruth, in Cornwall. The gas was generated in an iron retort, and conveyed in tubes to different situations, from whence it issued through proper apertures, and was there inflamed. Portions of the gas were also confined in portable vessels of tinned iron, and other substances, from which it was expelled when required, furnishing a moveable gas-light.

From this time forward, till about the year 1802, little more appears to have been done towards introducing this discovery to public notice. In the interval, however, Mr Murdock had made a number of experiments on the subject, and lighted up part of the manufactory at Soho; at which place a public display of the gas-lights was made in the spring of 1802, upon occasion of the general illumination for the peace then concluded at Amiens.

It has been asserted, that gas-lights were used in Paris previous to the British public being acquainted with them. The earliest date, however, assigned for their appearance is the winter of 1802: the gas used appears to have been obtained from wood.

In the years 1803 and 1804, gas-lights were exhibited in London; but a considerable time elapsed, and large sums of money were expended, before the metropolis was any way benefited by the introduction of Mr Murdock's discovery.

The first application, upon any considerable scale, of lighting by means of coal gas, was to the extensive cotton-mills of Messrs Philips and Lee of Manchester; the apparatus employed was erected in 1804 and 1805 under the directions of Mr Murdock, and it was found capable of supplying light equal nearly to what 3000 candles would yield. This system of lighting was shortly after adopted by many proprietors of cotton, woollen, and other manufactories in different parts of the kingdom, and has since been gradually introduced into most of the principal towns; and in America and on the Continent it appears to have been partially adopted.

About the year 1804, Mr Winsor, who had first exhibited the gas-lights in London, took out a patent for preparing and purifying coal gas; and, since that time, numerous others have been granted for effecting similar purposes; but, in general, their claims to novelty and utility are very limited.

Gases obtained from other combustible substances have been used for the purposes of affording light. Tallow, pitch, turpentine, turf or peat, some of the resinous woods and barks, all yield gases more or less fitted for the purposes of illumination; but with regard to the comparative economy of each, it does not appear that accurate results have been obtained from experience. Oil-gas has been extensively used, and will be treated of.

Apparatus requisite for preparing Coal Gas in a state fitted for the purposes of Illumination.

When pit-coal is made to undergo destructive distillation in a close vessel or retort, the products will, in general, be found to consist of the following substances; though, from the varying nature of the coal, they do not all exist in every species, some of them at least but very sparingly:

Coke or Charcoal. Tar and oil, two or three varieties. Water. Ammonia, partly as hydrosulphuret, and partly as subcarbonate. Carbureted hydrogen gas. Olefiant gas. Sulphureted hydrogen gas, besides portions of carbonic acid, of hydrogen gas, and common air; and also azotic gas, especially towards the end of the process.

The construction and management of the retort General will naturally come first under consideration; and in Process tracing the progress of the liquid and gaseous products, the condensing, collecting, and disposal of the latter come next to be treated of. The purification of the mixed gases, after they are separated from the tar and other liquids, forms an important subject of inquiry; and subsequent to which, the preservation of the purified gas in proper receptacles will be treated of. Its distribution to places where lights are required will then follow; and, lastly, a view of some facts relative to its combustion under different circumstances will complete this part of the subject. Of the Retort.

The retort first employed by Mr Murdock was made of cast-iron, and of a cylindrical form. See Plate LXXXI. fig. 1, where it is represented, as inserted into a common portable furnace: a, the retort; b, its cover made air-tight by luting; c, the tube or branch-pipe to convey away the gas and other products. This retort, being about two-thirds filled with coal, was submitted to the action of the fire; and, on its acquiring a red-heat, the decomposition of the coal commenced; the tar, oil, and gaseous products escaping through the tube c, and the charcoal or coke remaining behind in the retort.

It is obvious, that this form of retort is inconvenient, as regards the removal of the coke at the termination of each process, and, to remedy such inconvenience, a different construction was adopted, and which we saw in use as early as the year 1802. Of this a representation is given in fig. 2; a, the retort, consisting of a cylindrical vessel placed horizontally, with a door or cover b, to charge and discharge it of its contents, and branch pipe c to convey away the products of distillation; d the grate; the flues were so constructed that the flame surrounded the retort and afterwards made its escape at the chimney e. Retorts on this construction, from twelve to twenty inches diameter, and from three to seven feet in length, were found to answer tolerably well, and could be charged and discharged with facility.

Figures 3 and 4 represent the other varieties which we observed in use in the years 1804 and 1805. The peculiarity of these consists in their having each two openings or doors b and f, the first to admit the coal, and the other to allow of the discharge of the charcoal; a, d, c, refer to the same parts as in fig. 2. These retorts are necessarily more costly than those having only one opening, and they were, on the whole, found more troublesome to manage and keep in order.

Fig. 5 is a representation of one of the retorts first used at the works of Messrs Phillips and Lee, which differs little from fig. 1, except in magnitude, being made to contain about 15 cwt. of coal, while the other would hold only about the same number of pounds. The grate, flues, and chimney, and general construction, require no particular explanation, the letters referring to the same parts as in fig. 2. In order to facilitate the discharge of the cokes, an iron cage e, figured separate in the plate, formed somewhat like a grapple, was let down into the retort previous to its being charged with coal; and when the process of distillation was completed, the grappler was lifted out by means of a small crane, carrying the mass of charcoal along with it. Another grapple being then introduced, a fresh charge of coal was thrown in, and the process of distillation carried on with very little interruption. The quantity of gas produced from each cwt. of good common coal, obtained in the neighbourhood of Manchester, was from 330 to 360 cubic feet, when these retorts were employed, each yielding it at the rate of 160 cubic feet per hour on an average. The quantity of gas, however, varied considerably with the temperature at which the process was carried on; and the rate at Gas-Lights, which it was produced diminished greatly after the expiration of a few hours from the commencement of the distillation.

It is sufficiently obvious, from the construction of this retort, that, upon its being charged with fresh coal, and already of a red heat, the process of carbonization will proceed most rapidly at first; a crust of coke being speedily formed next to the heated metal, and this constantly increasing in thickness, prevents the free transmission of the heat, and the decomposition of the coal is consequently retarded more and more as the crust increases in thickness. As a remedy for this evil, and to which all the above forms of retort are liable (unless made of extremely small capacity, and thereby unfitted for practical use); one of the shape represented in fig. 6 was constructed, having an elliptical cross section, as shown at e, and placed, as regards the grate and brick-work, much in the manner of fig. 2, the letters referring to like parts. When filled about half full of coal, and previously brought to, and afterwards kept at a strong red heat, the quantity of gas produced was about 30 per cent. more than what the retort fig. 5 yielded, and the illuminating power, bulk for bulk, considerably increased. And the result of a great number of experiments, continued for a length of time, and under the varying circumstances of rapid and slow distillation, and large and small masses of coal, showed decisively, that the greater the rapidity with which the distillation was effected, the greater was the quantity of gas produced (from an equal weight of coal), and the more intense the illuminating power of that gas, volume for volume. The quantity of liquid product was also lessened, and the weight of the residual charcoal not so great as when the process was conducted with less rapidity.

The most advantageous results were obtained when the retort was heated to a bright red heat; when increased much beyond this point, so as nearly to approach a white heat, the production of gas was materially lessened.

We witnessed the above experiments, which were made at Soho, in 1807, and, as their results are of the first importance, the particulars of one series are given in the following table. The coal made use of was from the neighbouring collieries in Staffordshire, and of inferior quality, but that circumstance does not affect the comparative results of the experiments. The best Staffordshire coal will yield about 530 cubic feet of gas from each cwt.

<table> <tr> <th rowspan="2">No. of Experiment.</th> <th rowspan="2">Time of Distilling the Coal.</th> <th colspan="2">Cubic Feet of Gas produced.</th> <th colspan="2">Weight of Coke.</th> <th rowspan="2">Weight of the Tar, Water, and Oils.</th> <th rowspan="2">Time which the Gas supplied the Light of one Candle.</th> </tr> <tr> <th>Hours.</th> <th>lbs. oz.</th> <th>lbs. oz.</th> <th>Hours.</th> </tr> <tr> <td>1</td> <td>3</td> <td>41.3</td> <td>8</td> <td>8</td> <td>2</td> <td>3</td> <td>115</td> </tr> <tr> <td>2</td> <td>7</td> <td>37.5</td> <td>8</td> <td>8</td> <td>3</td> <td>1</td> <td>86</td> </tr> <tr> <td>3</td> <td>12</td> <td>33.5</td> <td>8</td> <td>13</td> <td>-</td> <td>-</td> <td>78</td> </tr> <tr> <td>4</td> <td>25</td> <td>31.7</td> <td>0</td> <td>9</td> <td>3</td> <td>3</td> <td>69</td> </tr> </table> The above table gives the results obtained from 56 lbs. of coal. This quantity was broken into small pieces, and mixed so as to render any portion of it of equal quality with the rest; it was then divided into four equal parts, each weighing 14 lbs., and these submitted separately to the action of the fire. In experiment No. 1, the retort was heated so as to complete the distillation in three hours; in No. 2, seven hours, &c. as specified in the second column. The third column gives the number of cubic feet of gas obtained in each case; the fourth, the weight of the charcoal remaining in the retort; and the fifth, that of the liquid products: the last column shows the number of hours which each portion of gas supplied the light of one candle; and these numbers are, therefore, expressive of the comparative value of the gas obtained in each experiment from an equal weight of coal. Generally, it was observed, that, in keeping these elliptical, or other flat-shaped retorts at a bright red heat, and introducing the coal into them when in that state, the quantity of gas was increased from one-third to one-half (compared with what the retorts fig. 5 yielded); the time of distillation greatly shortened; and the quality of the gas much improved; giving results, on the whole, not less favourable than those particularized in the above table.

The degree of heat, however, which was found to be most advantageous for the production of gas, was very destructive to the cast iron of which the retorts were formed; and to preserve these from rapid oxidation, their lower sides were made to rest upon thin firebricks, as represented in fig. 7, where the section of the retort is varied somewhat from the figure of an ellipse, as shown at n, to apply with greater exactness to the upper side of the protecting bricks g g; i, other bricks set on end to support the former, and standing upon an arch f, over the fire place; the flame, rising through the opening, e, and circulating at h h, underneath the bricks g g, escapes through two side flues, one of which is shown at k; and, after rising and passing over the top of the retort, enters the chimney: a, b, c, d, refer as in the former figures.

A somewhat simpler arrangement is shown in fig. 8, where the under side of the retort a is curved upwards, so as to apply directly to the back of a thin fire-brick arch, e, through which the heat is transmitted. The flame from the fire d, after acting against the brick arch, divides and escapes through the flues, f f; and, after uniting again at the upper side of the retort, ascends into the chimney. The conducting pipe is here shown issuing from the lower part of the door-piece b, and descends, instead of rising or passing away in a horizontal direction, thereby lessening its liability to be choked up by tar condensing therein.

This construction of retort is probably not inferior to any that has been used. When made of the dimensions represented (being drawn to a scale of one-fourth inch to the foot) it will contain about one cwt. of coal, when somewhat more than half filled, and produce gas at the average rate of 100 to 150 cubic feet per hour, according to the nature of the coal employed. With proper attention, it will work off six charges of coal in 24 hours; and last, when in constant use, from nine to twelve months.

The first description given to the public of an apparatus for producing coal gas for useful purposes, appears to have been in 1808, by Mr Samuel Clegg, in a paper transmitted to the Society of Arts. He therein describes a retort similar to fig. 2 in form, and protected from the immediate action of the fire by an interposed curved plate of iron. This cylindrical figure has been generally adopted at the gas works in the metropolis, and those of many provincial towns. Elliptical ones, similar to fig. 6, have, however, lately been introduced into the Westminster works; and, though much superior to the former, are yet less perfect than that shown in fig. 8, a construction which has been extensively used since the year 1808 in the northern manufacturing districts of England, and in Scotland.

Retorts, having for their vertical section a square or parallelogram, are also used (figs. 9 and 10), and these, as well as those of the cylindrical and elliptical shape, are occasionally placed so that two or three more are heated from the same fire; or a number of retorts, arranged with fires common to all. Figs. 11, 12, 13, 14 exhibit varieties of these; all, however, are liable to the objection that, when any retort becomes useless, those connected with it require to be stopped and disused during the time the faulty one is replacing. Constructions have been proposed which should admit of these repairs without causing interruption; but there is no great appearance of practicability in any plan for this purpose hitherto made public. When a number of retorts have to be heated from the same fire, any thing like regularity of temperature is difficult to obtain, on account of the different distances at which they must be placed from the source of heat; and, on the whole, except the circumstance of saving a little room, the plan has nothing to recommend it.

The fuel necessary to decompose any given quantity of coal may generally be stated at about one-third of its weight. There are statements published where less than one-fourth is mentioned as sufficient; but, where the retorts are to be kept at a proper, or bright red heat, so as to be capable of producing the largest and best supply of gas, less than one-third cannot be reckoned upon with certainty; and, as inferior coal is frequently used for fuel, the proportion may, in such cases, amount to, or even exceed, one-half the weight of the coal to be distilled.

It would much exceed our limits to notice every variety of retort which has been proposed. It may yet, however, be proper to notice another device for which the last person named obtained a patent, three to four years since. An outline of this machine, comprising an horizontal and vertical section, is drawn in fig. 15; a, a, a, a, is a flat cylindrical vessel of iron, having an aperture, b, at one side, and door to close it. In the centre is a vertical spindle, c, carrying a number of horizontal arms, d d; e is a representation of a pan or vessel for containing the coal, and with one of which each arm, d, is furnished. About one-third part of the lower and upper surface of the vessel, a a, is exposed to the action of a fire, f, and Lights, kept red hot; the flues, g g, conducting the flame to the chimney, in the manner shown in the figure; and the pans of coal (being, by means of the aperture b, introduced upon the arms d d) are brought in succession over the heated part, and there lowered, so that they may rest upon the red hot surface. The distillation is thus carried on, and, when completed, the axle is turned partially round, and another pan, or set of pans, exposed to heat in the like manner. This is a complex and expensive apparatus; and, inasmuch as the coal is not brought into immediate contact with the red hot surface, it must necessarily be inferior in performance to the elliptical or other forms, figs. 6, 7, 8; and, though there are statements before the public which represent the results in a very advantageous light, these must be received with caution. It is mentioned,* that, by the use of this retort, 16,000 cubic feet of gas, and upwards, may be obtained from one London chaldron of Newcastle coals, being 590 cubic feet to the cwt.; and that the same weight of coal distilled in a cylindrical retort will not give more than 370 cubic feet to the cwt. By using flat elliptical retorts, however, and exposing the coal in very thin layers, upwards of 600 cubic feet have been obtained; and, for general practice, where the coal is of good quality, 500 to 550 cubic feet may be calculated upon as the product of each cwt.

The quantity of gas which one chaldron of Staffordshire coal yielded, when distilled in the retort last described (fig. 15), was, according to Mr Accum, 11,000 cubic feet, or about 400 to the cwt. This falls much short of what has already been stated as the product of the best coal from that district.

A retort constructed so that the coal (broken small) could be exposed in very limited quantities at once to the action of the fire, and, at the same time, scattered so as to cover a large surface of the heated vessel, would be desirable. The constant charging and discharging of such a retort, however, where each process of distillation would be completed in a few minutes, is a serious objection. Forms have been devised for effecting these ends during the carbonization of a number of successive portions of coal, without opening the doors of the retort; but the internal machinery requisite for this purpose is liable to derangement and uncertainty of action, owing to the great heat it must necessarily be exposed to. We have not hitherto seen or heard of any constructions wherein the requisites of simplicity, durability, and certainty of effect are attained to such a degree as to warrant their being substituted for others, the results of which are known from long experience.

The quality of coal gas varies considerably during the period of distillation, the first products usually containing carbolic acid, olefiant, and sulphurated hydrogen gases; while those obtained towards the end of the process contain hydrogen gas and carbolic oxide. The quantity of gas produced in a given time varies also very considerably: such a retort, as is shown in fig. 8, will generate it at the rate of about three cubic feet per minute at the commencement, and continue to do so, or with little variation, for nearly two hours, when the quantity rapidly decreases till the end of the operation, which will occupy from three and a half to nearly four hours, when the retort is kept at a proper temperature.

Separation of the Gaseous and Liquid Products obtained from Coal.

It has already been stated, that the liquid substances obtained from coal by distillation are tar, oil, and water; the latter generally holding in solution a portion of hydrosulphuret and subcarbonate of ammonia. As all of these leave the retort in a vaporous state, the condensation of this vapour is an object necessary to be attended to, and it is more or less perfectly effected by passing the same through tubes or vessels surrounded with cold water, or otherwise exposed to a cooling medium.

Refrigerators for this purpose have been variously constructed; some differing, in no respect, from the worm of a still-tub; others so arranged as to present broad, flat, or curved surfaces to the action of the cooling body;—all these, and similar contrivances, do not, however, effect the separation of the tar and oils;—a minute portion remains suspended in the gas, of which it is not easily deprived. Time and stillness, or the absence of agitation or currents, have a considerable influence in inducing a deposition; and by constructing the internal parts of the condensing apparatus very large and roomy, as regards their transverse section (but, at the same time, of forms exposing a great surface), the gas is required to travel through it with a proportionably slow current, thereby giving the tar a better opportunity of depositing, than if the vessels were of a less area of section, and greater in extent otherwise. It is therefore of little consequence of what particular forms the condensing vessels are made; a flat tube, of considerable area, placed perpendicular, or nearly horizontal (and surrounded with water), and extended in one continued line or otherwise, as circumstances will admit of, and having proper apertures for the admission and discharge of the gas, and a suitable reservoir and outlets for the tar and other fluids, will be found to answer the purpose as well as constructions of greater complexity.

Such an apparatus is represented in Plate LXXXII. fig. 1, where a a is a water-tight cistern; b b, a range of tubes placed vertical, connecting with each other as shown; c, entrance-pipe for the gas, and d, that where it makes its exit; e, a pipe to convey away the tar and other condensible liquids which fall down into the lower part of the vessel, f f.

Another construction is represented in fig. 2, where a a is a close cistern or vault of brick, stone, or iron, having an opening b, for admitting the whole of the volatile products of the distillation; another

* Accum's Description of the Process of Manufacturing Coal Gas, 1819, p. 44. at c, for drawing off the tar and other fluids at any particular level, the pipe there attached being made to slide vertically through a stuffing box. A vertical partition is placed in the vault, extending nearly the whole of its length, to cause the gas to circulate through it previous to its passing into a third opening d, which conveys away the crude gas, and so much of the tar, &c. as has not got deposited in the vault a; e e, a water-tight cistern of iron or other material, through which a current of cold water is continually circulating; it may either be placed over the former, or in any other convenient situation, and the pipe ffff, traverses this vessel as shown, sloping gradually upwards till its termination at k, where it passes forward to the purifier. The gas in its ascent along this pipe is exposed to the action of the cold surface, and the tar and oils which are thereby condensed run back into the vault a a.

It is not easy to assign a limit to the magnitude of this part of a coal gas apparatus; the slower the passage of the gas through it, and the larger the capacity of the tar-vault and condensing tubes, the more perfect will the separation of the tar and gas be. But, in fixing the opposite limit, it will be advisable to make these of such capacity, that each portion of the gas may be detained at least three quarters of an hour in its passage through the same.

The quantity of tar, and other liquid products, yielded by a given weight of coal, varies considerably, not only according to the quality of the coal, but from the manner in which the decomposition has been effected, and which has already been spoken of. One cwt. of good cannel coal gives, when distilled at a bright red heat, from six to seven lbs. of tar and oils, and commonly about half that weight of water, making together one ale gallon or thereabouts.

Separation of the Gases unfitted for the purposes of Illumination.

These, in general, consist of sulphureted hydrogen, carbonic acid, carbolic oxide, and hydrogen gases.

To separate them entirely from the carburetted hydrogen and olefiant gases forms no easy task, and in gas-light establishments attention has principally been paid to the first of these; and though the means used to detach the sulphureted hydrogen have also served to take away the carbolic acid, neither the separation of this acid gas, nor that of the other gases above enumerated, have been considered of much importance.

It has been already noticed, that the sulphureted hydrogen and carbonic acid gases are produced principally at the commencement of the distillatory process, and disappear almost entirely towards the end. From the experiments of Dr Henry,* it appears, that gas from Wigan cannel contained about 5 per cent. of each of the above, and other varieties of coal from different parts of the kingdom, furnished results of a similar nature; but unless care be taken to make use of coal, separated as much as possible from the common pyrites with which it frequently abounds, the quantity of sulphureted hydrogen gas will be increased very considerably, and its separation be but partially effected by the application of cream of lime, as commonly applied. Potash, and some other substances, on account of their costliness, have not been made use of, at least on any large scale; and though various plans have been proposed for absorbing the sulphureted hydrogen gas, it does not appear that any have been found to answer in which lime was not the principal agent, and used either in the shape above mentioned, or more or less combined with water.

Chlorine, from its property of uniting with sulphureted hydrogen gas, has been proposed as a fit substance for the purification of coal gas. The impossibility, however, of presenting the two gases together, in proper proportions, would be a sufficient reason for not using it, were others wanting. Chlorine, however, acts upon olefiant gas, as appears from Dr Henry's account (Man. Mem. Vol. III. new series), in which objections are also mentioned to another proposed plan of purification, by passing the gas through red hot iron tubes.

Washing the crude coal gas with water alone has frequently been practised, but very little benefit can result. A simple, but very ineffectual mode of purifying the gas by the action of lime cream, and which was practised for a considerable time, consists in merely forcing the gas through a tube, or tubes, terminating a few inches beneath the surface of the fluid, as represented in fig. 3; a a, a close vessel having pipes b, c, d, e, attached to it; the first of these serves to introduce the lime cream, the second to admit the gas, the third to take it away, and the remaining one to draw off the lime and water. The vessel being about half filled with the liquid, gas is forced in at the pipe c, and on making its escape at the lower extremity, it rises up in bubbles, exposed to the action of the lime, and is thereby somewhat purified; and when the liquid is supposed to be saturated to a certain degree, it is drawn off, and a fresh supply introduced.

Another variety of purifier is represented in fig. 4: a a is an oblong close vessel, having a number of vertical partitions made fast to the top and sides, but not reaching to the bottom; these are pierced near their lower edges with a number of small holes; c, pipe to introduce gas, and d, one for conveying it away; lime cream being put in by means of the vessel b, to the height shown, the gas is forced forward, and passes, exposed to the action of the lime, through the perforated plates one after another, and finally escapes at d.

In order more fully to expose the gas to the action of the lime cream, a variation from fig. 3 has been effected, and is used in some of the gas-lighting establishments in London and elsewhere. Fig. 5, a a a a is a flat cylindrical vessel, having tubes c and d for the entrance and exit of the gas; b, a bent tube communicating with the vessel a, and through which the lime cream is introduced; e, a

* Philosophical Transactions for 1808, and Manchester Memoirs, Vol. III. new series. pipe and valve to draw off the same when requisite; f f, an inner cylindrical vessel, having a broad flanch or plate, g g, attached; h k, a vertical axle, working through a stuffing box, and carrying an agitator near its lower end. Lime-cream is introduced to the level shown; the gas, on being forced in, fills the interior cylinder f f, and escapes along the under side of the broad flanch g g, and is there greatly exposed to the action of the liquid, and which action is increased by the motion of the agitator. After passing the flanch g, the gas escapes into the upper part of the outer cylinder, and is conveyed away by the pipe d. In order to render the purification more effectual, two or three of these vessels are connected together, so that the gas passes through the whole of them; and by discharging the liquid from one at a time, the irregular action, which would otherwise be experienced, is in some measure done away.

In fig. 6 is shown a different construction of purifier; a a a a, a close vessel, and containing an internal one b b, open at the bottom, and furnished with a number of notches along each of its sides; the pipe c, which brings in the gas, communicates with the inner vessel, the discharging pipe, d, with the outer one. Lime-cream is admitted from a proper vessel, e, through the pipe f, until the notches, above mentioned, are covered; g g, an axle passing through air-tight collars at one end of the inner and outer vessels, and furnished with a handle or winch to turn it round by; this axle carries a number of short arms, or levers, corresponding to the notches of the inner vessel, each of which passes through two of them during every revolution of the axle; the use of these arms is partly to agitate the lime-cream, and partly to keep the notches clear from the incrustation of the lime. This contrivance forms a part of one of Mr Clegg's patent inventions, the other parts of which, as they relate to a complex apparatus for discharging the lime after using, are here omitted. The lime-cream may be taken off by a pipe similar to e, fig. 5, attached to the lower part of the vessel.

From the principle on which all these purifiers are constructed, it is obvious, that where only one is used, the process must be carried on with extreme irregularity; for if when each charge of lime-cream is first admitted, a proper degree of purification is effected, the same cannot continue with any degree of uniformity, but must gradually become less perfect till the lime is discharged; and though this defect may be in some measure remedied by using two or more purifiers, even then the action cannot be very uniform. Fig. 7 represents a purifying apparatus, which, though it obviates the want of regularity above mentioned, has been found somewhat troublesome to keep clean, from the difficulty of getting into the inside to remove the lime which adheres internally: a a a a, is a close vessel with pipes, communicating at c and d, to take the gas in and out; f f, a cistern surmounting the vessel a, and this is surrounded by another cistern g g, somewhat deeper than the former; h h are partitions, or shelves, placed nearly horizontal within the vessel a, and fitting to its internal cavity, except at one edge, as represented; lime being put into the external cistern, and water admitted by means of a cock, or pipe, the mixture overflows into the inner cistern, and, passing through the tube b, traverses gradually to the bottom of the machine, forming thin sheets of liquid as it descends from shelf to shelf, and through which the gas has to make its way in passing upwards. The lime-cream is thus constantly supplied from the outer cistern, and as constantly running out by the pipe e, after it has performed its office. The effect which such a purifier can produce, must, unless made of very large dimensions, be somewhat limited, and without a construction to which mechanical force can be effectually applied, the process will be accomplished but in an imperfect manner.

A purifier, where the lime can be regularly admitted and discharged, is mentioned in a late publication (Peckston on Gas-Lights, p. 408) as of very recent invention; its particular construction, however, is not manifest from the description there given.

In fig. 8 is represented the vertical section of a purifying machine, which, while it has the property of regularity of action, also admits of a very effectual application of its powers: a a, b b, is a cylindrical vessel placed in an oblique direction, and having a number of internal partitions, h h, standing up nearly to its axis, in which is placed a spindle, k k, carrying a number of arms, l l; these act as agitators, and also are capable of scooping up portions of the lime-cream, which is represented as contained in the different cells formed by the partitions h h; a a, f f, a vessel forming an addition to the upper end of the cylinder, and closed on all sides except where it joins to the cylinder, and where the exit gas pipe, d, and the lime admitting tube, e, are inserted; it is surmounted with a cistern, g g. Through the aperture e, a vertical axis descends, giving motion to the inclined one k, by means of two conical wheels: m, an inverted cup, and n, an agitator, both fixed upon the vertical spindle. The lower end of the cylinder is united to a vessel p p, closed like the upper one, except where it joins at b b, and having an admission pipe, c, for the gas, and a pipe, q, to take off the impure lime-cream. The cistern, g, is supplied with water by means of a pipe, or otherwise, and the axle being kept in motion, lime is put into the cistern, g, and there mixed and stirred about by means of the agitator, n; from this it descends into the cylindrical vessel, and is collected in the uppermost cell, from which situation it is scooped up and dashed about by means of the arms, l, and a part of it constantly dropping down past the uppermost partition, is then received into the next cell, and the same process is regularly going forward the whole length of the cylinder, the lime-cream finally escaping at the pipe, q, in an impure state. The gas, in its ascent upwards in this machine, has to pass among all the arms upon the inclined axis, and to encounter perpetual spray, and showers of the lime-cream, which are constantly renewed, the supply being regulated by the quantity of lime and water introduced into the upper cistern.

If a purifying apparatus were constructed, in which the properties of figs. 6 and 8 were combined, it would probably be found more complete than any one at present in use; the essentials being a constant supply of lime-cream, and its proper application; and the means of making the machine, by its common action, keep itself free from obstructions by the clogging and adhering of the lime to its different parts.

The quantity of lime necessary to purify a given bulk of gas will no doubt vary considerably, according as the coal used is more or less free from admixture with impurities, affording sulphurated hydrogen gas on distillation: the weight of lime, compared with that of the coal distilled, has been stated at from 1-30th to 1-10th, but the application of tests from time to time to portions of the gas, will be necessary in order to know what proportion of the purifying mixture ought to be employed. By forcing a quantity of gas through a weak solution of acetate of lead (formed by dissolving three or four grains of it in a two ounce phial of water), the natural milkiness of the solution will assume a dark cloudy appearance if sulphurated hydrogen gas is present. Water impregnated with this gas assumes a black appearance on the addition of a drop or two of nitrate of silver. A current of gas containing sulphurated hydrogen, directed against the surface of a card or other substance which has been painted over with white lead ground up with water, will immediately discolour it.

A patent has lately been obtained for purifying coal gas by passing it through strata of recently slackened lime in a nearly dry state. With regard to the actual absorbent powers of lime, as exposed to the presence of sulphurated hydrogen gas, no accurate accounts appear to have been published; but it is not probable that the performance can equal that effected by an equal quantity of lime made into cream, and differently applied.

Reservoirs or Gasometers suitable for containing the Gas.

The simplest and best of these is the common gasometer, consisting of a cylindrical or prismatic vessel open at the bottom, and suspended over water by means of a lever or pulleys, with chain and counterbalance weights; a machine with which chemists have been familiar since the days of Lavoisier, with whom it appears to have originated, and who published a description of it in 1789.

Watt's air-holder, for containing inflammable or other airs or gases, though known to the public for upwards of twenty-five years, has now been made the subject of a patent, as applicable to the purposes of a coal gas reservoir, but for which it is not at all suited, however appropriate to the originally intended purposes of containing gases, and transporting them from one place to another.

It has been proposed to diminish the size of the vessels used for containing gas, by forcing it into them in a greatly compressed state; but unless the gas-holders for this purpose are made enormously strong, any great degree of compression cannot be attained with safety. Small portable vessels, containing gas in a compressed state, have been used for supplying light; one of these was exhibited at the Royal Institution in 1816 or 1817 (Quarterly Journal, No. 16); and, in 1819, Mr D. Gordon obtained a patent for a similar apparatus.

A variation from Lavoisier's gasometer has lately been used in some gas-light works, in which the pulleys and counterbalance are omitted, and the inverted vessel kept in a vertical position by guides which allow of its rising or falling, as the gas is forced in or suffered to escape. This is a very imperfect machine, as subjecting the gas to a varying pressure, and which has, therefore, to be regulated, as will be shown hereafter. Other constructions have been proposed and employed, also subject to the irregularity just mentioned.

In all cases where a steady light is required, it is of importance that the supply of gas be uniform, and therefore requisite that the pressure or force with which it is expelled the gasometer, should be always precisely the same. A gasometer on the construction first above mentioned is represented in Plate LXXXIII. fig. 1, where a a is the vessel for containing the gas, inverted over a cistern of water b b; and suspended from the pulleys c c, by means of the chain d, and counterpoise e; f f are tubes for bringing in and conveying away the gas.

The gasometer, like any other body, immersed in water, of course loses a portion of its weight equal to that of the water which it displaces; and it has therefore the less power to expel its gaseous contents the deeper it is immersed. To remedy this irregularity, additional weights are added from time to time to the gasometer as it descends, and removed again as it rises; but this method, though at present in practice in some places, is very imperfect and troublesome.

By making the chain d of a proper weight, it may be made to answer the purpose of a regulator of the pressure. Let it be supposed, for example, that the gasometer weighs 1000 lbs. and loses 100 lbs. of that weight when immersed in the water; and that a portion of the chain, equal in length to the height which the gasometer rises, shall weigh 50 lbs. and the counterpoise weigh 950 lbs.

Then, when the gasometer is immersed, its effective weight is

\[ \frac{1000}{900} \]

To which must be added the portion of chain now acting, as increasing the weight (of the gasometer),

\[ \frac{50}{50} \]

The sum corresponds with the actual weight of the counterpoise,

\[ \frac{950}{950} \]

Again, let the gasometer be elevated out of the water, its actual and effective weight then is

\[ \frac{1000}{1000} \]

To balance which is opposed the counterpoise,

\[ \frac{950}{950} \]

And the portion of chain now removed to the other side of the pulley on which the counterpoise is, and acting with it,

\[ \frac{50}{50} \]

The sum corresponds with the actual weight of the gasometer,

\[ \frac{1000}{1000} \]

This method, though it effects the purpose of equalizing the action of the gasometer and counterpoise as opposed to each other, is less complete than the following: Let the counterpoise (instead of being formed as shown at e in the figure) be allowed to descend into the water, and consist of a long cylindrical or prismatic body as represented by the dots g g, having the area of its horizontal section equal to the area of a similar section of the plates, or substance of which the gasometer is formed; and let the chain d be of a weight equal (length for length) to a column of water of equal bulk with the counterpoise.

For instance, let the gasometer, as before, weigh,

in air, lb. And, in water, say, The counterpoise also to weigh, in air, And, when immersed, like the gasometer, And, a portion of the chain equal in length to the space through which the gasometer rises or falls, weigh Then, when the gasometer is immersed in water its effective weight is To which must be added the chain now assisting it as weight, Sum, corresponding with the weight of the counterpoise,

Reversing the case, let the gasometer be out of water, it then weighs

The counterpoise now immersed, its effective weight is And the chain, now assisting the same,

Gives a sum of lb. 1000, corresponding to the weight of the gasometer; and in every point of the ascent and descent, this opposite equality will be found to exist.

It will have occurred to the reader, that gasometers counterpoised in the ways above described, can have no power to expel their contents; but it is obvious enough that the counterpoise may be lessened in weight so as to cause any given pressure on the gasometer, but without affecting the equality of such pressure.

Were the gases made use of for illumination, of the same specific gravity with atmospheric air, the above method of adjustment would be perfect, but as the specific gravity of coal gas is considerably less than that of the air (being only about two-thirds of it at the common atmospheric pressure), a compensation for this is requisite. The gasometer, when filled with such gas, will, of course, require a less weight to counterbalance it than it otherwise would if filled with air, and the weight of the chain must be therefore lessened as will now appear.

Let it be supposed (in consequence of the le- vity of the gas) that the gasometer, when filled,

and its horizontal section must be lessened, so as to displace, of water, only 45 lbs.; and the portion of chain above mentioned must weigh only 45 lbs.

will then be found, that, as in the former case, an equilibrium subsists between the gasometer and counterpoise.

We have seen, where a sufficient depth of cistern was not obtainable, a form of gasometer, represented in fig. 2, adopted. This consists of two parts, detached from each other; the inner one, a a, being of itself a gasometer of the common construction, but surrounded with a channel, b b, containing water, and which, as it rises up, connects with the outer part, c c, and carries it upwards also; the two forming together one gasometer. In like manner, more outer parts might be added, but the thing is sufficiently complex, as shown; d d are pulleys, with weights just sufficient to counterbalance the outer part, c c, but not to elevate it without the assistance of the weight, e. Other contrivances have been proposed for saving of room on somewhat similar plans, but, like the above, they are not deserving of much attention, and only proper to be resorted to in cases of necessity.

Fig. 5 is another variety of gasometer, which appears lately to have got into use, though it is very imperfect, or rather totally deficient in the essential property of giving an uniform pressure to the gas contained within. Having no counterpoise, it requires to be elevated by the forcing in of gas under a considerable and varying pressure, and the addition of a regulator or governor (described hereafter) is necessary to equalize that pressure where the gas is emitted for the purposes of combustion. The parts, a a, b b, f f, are similar to those of fig. 1, but instead of the pulleys and counterpoise, the gasometer moves vertically upon the slides, c c. A species of counterpoise is sometimes applied to this gasometer, consisting of a vessel z, open at the bottom, and attached by its top to that of the gasometer; as the gasometer sinks, the air in this vessel becomes compressed more and more, and exerts itself so as to act as a counterweight in some degree.

Fig. 7 is a revolving, or partially revolving, gasometer, described by Mr Clegg, with whom the contrivance originated: a a a, a cistern nearly filled with water, as shown; b, an axle, hollow at each end, and working on friction sectors; d d d, a vessel supported by arms radiating from the axle, and formed of parts of two concentric cylinders, closed at their ends, and also closed at g, except where the entrance and exit gas pipes, passing from g to the hollow axis, are connected (one of these is only shown in the figure, the other being directly behind it); the end, h, is open, and when the gasometer is filled with gas, it is just immersed in the water; i, a pulley, to which is attached a chain and weight, k, disposed as represented. The whole apparatus is constructed so as to be in equilibrium in any position, the framing being made heavy at that part of the circle to which the gas-holder does not extend, so as to counterbalance the matter opposed to it. The gas enters at one of the hollow ends of the axis, and passes through one of the tubes g, into the gasometer; and it is discharged, under any required pressure (obtained by means of the weight k), through the other tube behind g, into the farther extremity of the axis. This form of gasometer is somewhat expensive; but, from the circumstance of its requiring a shallow water cistern, may be resorted to in some cases with propriety.

The vertical section of another of Mr Clegg's devices, and which he calls a Collapsing Gasometer, is shown in fig. 8. The sides close together like the two boards of a book, and the formation and action of the ends cannot be better described than by a reference to the opening and closing of the folding divisions or pockets of a pocket-book. The difficulty of making such a length of joint gas-tight will be found no small objection to the use of this gasometer; and the single advantage it appears to possess is the shallowness, and consequent cheapness of the cistern \( a \), in which it is placed. The balance weights \( b, b \), act upon the bent levers \( c, d; c, d \); which cross each other, and are attached to the sides of the vessel, and with the pressure of the gas cause the same to expand or collapse as required; imitating (in effect) the rising and falling of the common gasometer. This construction scarcely admits of an uniform pressure being given to the gas when expelled, and that must, therefore, be accomplished by means of a regulator attached to it.

Gasometers are usually made of sheet iron of from two to three lbs. to the square foot, with internal frame of wood, cast or bar iron. When constructed to rise and fall vertically, as in figs. 1, 2, 5, a cylindrical form is to be preferred, as the water pits, or cisterns over which they are suspended, are more easily constructed of that shape, than of square, oblong, &c.

Various methods of suspending gasometers have been adopted, the principal end in view being, as above stated, to equalize the pressure as much as possible; and, in the furtherance of this object, it is desirable to make the working parts of the machinery on a construction the least liable to the effects of friction. The pivots, or axes of the suspending pulleys, are usually placed on friction rollers or sectors, such as are represented in figs. 3, 4, 7; the first of which we consider as the most perfect, having seen it applied to gasometers of great magnitude with all desirable success; there being no other friction than that occasioned by the steel edges \( a a \), which carry the whole, and work upon bolsters of the same substance: \( b b \) are two sectors, having the curved parts on which the pivots of the pulley \( e \) roll, concentric to the edges \( a a \). The application of two sets of these to a gasometer is shown in Plate LXXXIV., where the counterweight is represented as working within a central tube, thereby making the arrangement very compact. In this plate are also shown weights to preserve the sectors in equilibrium, and counteract the effect which would otherwise be produced when they are moved from a vertical position.

Fig. 4, Plate LXXXIII., represents the axis of the pulley \( c \), working upon friction rollers (\( a a \), with their support \( b \)) of the common construction. In fig. 7, the axis of the gasometer works upon a sector somewhat similar to fig. 3 reversed; but this form renders it necessary that the axis shall be kept in its proper situation by means of a double or forked frame as shown, and thereby causing a certain degree of friction from which fig. 3 is exempt.

The manner of conveying the gas into and out of the gasometer, delineated in figs. 1, 2, 5, is the simplest and best when it can conveniently be practised. It, however, sometimes happens that access to the lower part of the pit or cistern is difficult to be obtained, and other means have to be resorted to. Swivel or flexible jointed tubes, arranged so as to rise and fall with the gasometer, though they answer well enough on a small scale, are with difficulty made of large capacity so as to have little friction. We have seen jointed tubes connected by means of water-lutes extensively used, and which answer well the intended purpose; one of these is represented in fig. 6, \( a \) being the pipe where the gas is introduced; \( b \) a vertical pipe capable of a small angular motion on the axis or support \( c \), and connected with \( a \) by means of a water-lute joint; its upper end is also connected in a somewhat similar manner to one end of the pipe \( d \), and again at \( e \), another moveable water-joint is placed; \( f \) is the pipe connecting with the top of the gasometer; \( g \) a regulating radius bar centered to a bracket attached to the pipe \( d \), and working on a fixed pivot at \( i \). The gasometer rising or falling, carries \( f \) along with it, and in the rest of the apparatus a motion is induced, corresponding with the connection of the different parts.

Having more or less minutely described different constructions of gasometers, it may be proper to explain the nature of such contrivances as have been introduced to render uniform the pressure of the gas issuing from such as do not possess the means of regulation within themselves.

Fig. 17, Plate LXXXI. represents one of these go- The Governors, consisting of a crooked tube \( a a a a \), with a nor conical valve seat fixed in it at \( b \); \( c \), a valve fitting the seat when shut, and having a stem carried upwards and connected with the inverted conical vessel \( d d \); \( e e \), an exterior vessel, in which water is contained to the level represented. The gas enters at the bottom tube, and passing through the valve, escapes at the other horizontal extremity of \( a \), and at the same time fills the upper part of the inverted vessel \( d d \), and raises it more or less according to the pressure and velocity with which the gas enters; thereby partially closing the valve as the pressure increases or diminishes, and thus regulating the quantity of gas discharged through the machine.

Fig. 18 is another regulator or governor, not differing in principle from the former; the gas enters at \( a \); \( b \) is the valve seat; \( c \) the valve with stem connected to the inverted vessel \( d \), which is suspended in a cistern of water \( f f \), and moves upon a pivot at \( e \). The action of this apparatus is similar to that of the former one, and of the two, it is of a construction more likely to answer the intended purpose.

Regarding the distribution of gas for the purposes of supplying light in distant and different situations, a few remarks may be made.

The pipes or tubes for this purpose are best when made of cast iron with socket joints, and put together with lead; and for smaller sizes than what are manufactured of cast-iron, welded or brazed plate iron connected by screws, may be used. Copper tubes are objectionable, on account of the action of the gas upon that metal if not perfectly purified; those of block-tin, lead, and some mixed metals, answer well enough when made sufficiently strong to resist external injury.

As the gas always carries along with it a quantity of aqueous or other vapour, it is requisite to lay the pipes so, that this, when condensed, can be collected and drawn off from time to time. A small declivity is, therefore, to be made towards one or more points, where cocks, closed vessels, or inverted siphons, are to be placed, to collect and take off the water, &c. accumulating. For stopping off the gas in large pipes, waterlute valves are generally used, one of which is represented in fig. 16, wherein a is the valve, formed like an inverted cup, with rod (working through a stuffing box) attached, and handle above; b, an annular cavity containing water, into which the valve, when shut, falls. This is about the simplest, and probably the best form of valve, and though others of a more complex nature have been used, they do not appear better adapted for the required purposes.

It has been usual, in practice, to allow half a cubic foot of coal gas per hour for the supply of a light equal to that of a mould candle of six to the pound, and of which one pound will, when the candles are burnt singly, last 40 hours. If the gas, however, is properly prepared, and burnt under favourable circumstances, it does not, in point of fact, require above one-third of a cubic foot to produce such light, as will be hereafter shown. But, taking the common allowance, the sizes of pipes necessary for transmitting gas to supply various quantities of light, under the pressure of a column of water, of from five-eighths to three-fourths of an inch, and making very ample allowance for friction, may be stated as follows:

<table> <tr> <th>Diameter of Pipes in Inches.</th> <th>Number of Candles' Light to be supplied.</th> </tr> <tr> <td>\( \frac{1}{2} \)</td> <td>20</td> </tr> <tr> <td>1</td> <td>100</td> </tr> <tr> <td>1\( \frac{1}{2} \)</td> <td>240</td> </tr> <tr> <td>2</td> <td>450</td> </tr> <tr> <td>3</td> <td>1,000</td> </tr> <tr> <td>4</td> <td>2,000</td> </tr> <tr> <td>5</td> <td>3,400</td> </tr> <tr> <td>6</td> <td>5,000</td> </tr> <tr> <td>8</td> <td>9,000</td> </tr> <tr> <td>10</td> <td>14,000</td> </tr> </table>

It frequently happens, where gas-lights are used, that the times and periods of burning them are very irregular; thereby rendering the quantity of gas consumed a matter of uncertainty, subjecting both the manufacturer of the article and the consumer to the liability of not being fairly dealt with by one another. To remedy this evil, and generally to ascertain the quantity of gas manufactured, different modes of measuring it have been proposed. Gasometers, suited in size for each consumer, and filled from time to time with gas from proper feeding pipes, though they would answer the intended purpose, are objectionable on the score of expence, and the room they would occupy, and the trouble, which would be considerable, of attending them; and though it is by no means impracticable to construct such, with a self-acting apparatus attached, for filling it, and registering the quantity of gas admitted, yet the cost would, in most cases, more than counterbalance all advantage to be derived from it.

A self-registering gas meter, of a cheap, efficient, and generally applicable construction, would be an object of considerable importance to manufacturers of gas. In the Repertory of Arts for February 1817 is described an exceeding complex apparatus for this purpose; which, as it has been abandoned in practice by Mr Clegg, the patentee, need not be explained here. A much simpler and better machine for this purpose is described in a late work (Peckston on Gas-Lighting), and of which sections are given in Plate LXXXII. fig. 12, where c c represents the outside casing, in form of a flat cylindrical drum, having a bent tube, a, inserted at its centre, for admitting the gas, and a branch, b, for conveying it away; g g, are two pivots, one supported from the tube a, and the other from an external water-tight cup, projecting from the outside casing, and in which is contained a toothed wheel, h, fixed upon the pivot, and connected with a train of wheel-work (not shown in the figure), to register its revolutions. The pivots are fixed to and support a cylindrical drum-shaped vessel, d d d, having openings, e e e e; internal partitions, e f, e f, e f, e f; and centre piece, f f f f; all of which will be understood best by inspection of the figure. The machine is filled with water (poured in at h) up to the level of i; and gas being admitted under a small pressure at a, it enters into the upper part of the centre piece, and forces its way through such of the openings, f, as are from time to time above the surface of the water; and, by its action upon the partition nearest in contact with the water (to the right hand of that figure in which all the partitions and openings are shown), a rotatory motion is produced; the gas from the opposite chamber being at the same time expelled by one of the openings, e, and escaping at b, as before-mentioned.

The quantity of gas discharged by this machine in any given time, depends not only upon its internal dimensions, and number of revolutions made, but also upon the level of the surface of the water within it; and, as such discharge of gas will be greater or less, as the quantity of water is less or more, attention to its being kept at a proper level is of the first consequence to the due action of the meter; and for this reason, means must be employed to insure a supply of water, and a suitable outlet provided, to prevent its accumulating in an undue quantity.

For the combustion of gas, burners, of many different descriptions, have been used, and the gas made to issue through apertures of almost every variety. Experience, however, has proved, that small circular holes, of from one-fortieth to one-sixtieth of an inch diameter, are most advantageous; and these Gas-Lights. are disposed in various figures, so as to form lights of one or more jets, and in circles to resemble the burners of the argand lamp.

Particular attention should be paid to construct burners so as to allow the atmospheric air to come freely in contact with the flame; and, for this purpose, when a single jet or light is wanted, the perforation may be made at the point of a small cone, as at a, fig. 9; and, for additional lights, other apertures, b b, are added near its base; such, having three flames or jets, as represented, have been named cockspur lights. Fig. 10 is a bat-wing burner, where the flame issues from a narrow slit cut across its top.

When lights are required equal in intensity to four or more candles, the arrangement of the holes in a circle, with a central opening to admit atmospheric air, and with exterior cylindrical glass, as in the argand lamp, is to be preferred; and burners giving the light of 10, 15, 20, or a greater number of candles, may be advantageously used on this construction, varying the diameter of the luminous ring according to the number of apertures required. Fig. 11 is a full-sized representation of a burner with 12 holes, c c, having an air tube, d, in the centre of half-inch diameter; a, the branch through which the gas is admitted into the cylindrical cavity, b b, in which it circulates during its passage to the orifices c c; this burner may, with propriety, be used to give the light of six or eight candles. Much smaller ones, where the air-tube, d, is less than about three-eighths of an inch, do not answer well; as the atmospheric air is apt not to circulate through them, and the flame unites, in consequence, into one smoky mass.

Count Rumford (Essay XVI.) details a number of experiments on the comparative economy of different sized flames, produced from various burners applied to an argand oil lamp, and from which it appears that there is a certain varying proportion betwixt the diameter of each burner, the intensity of the light, and the quantity of oil consumed; the consumption of oil being greatest in proportion to the light obtained when the flame was small, and gradually lessened as the light was enlarged, until it began to smoke, when the proportional consumption of oil again increased. With an argand burner of about \( \frac{7}{16} \)th inch diameter at the middle of the flame, he tried the proportional consumption of oil when the light was regulated, so as to be equal to that of a successive number of candles, of from 1 to 10; the result, in grains of oil, which gave an equal and corresponding quantity of light for one hour, are given in the following table, and the quantity necessary to supply the light of one candle in each case is also added.

<table> <tr> <th>Candles (wax, 5 of which are equal to 4 of those mentioned in another part of this article).</th> <th>Grains of Oil per hour consumed, to give light equal to the corresponding number of Candles.</th> <th>Grains of Oil equal to one Candle.</th> </tr> <tr> <td>1</td> <td>246</td> <td>246.0</td> </tr> <tr> <td>2</td> <td>300</td> <td>150.0</td> </tr> <tr> <td>3</td> <td>329</td> <td>109.6</td> </tr> <tr> <td>4</td> <td>390</td> <td>97.5</td> </tr> <tr> <td>5</td> <td>437</td> <td>87.4</td> </tr> <tr> <td>6</td> <td>476</td> <td>79.3</td> </tr> <tr> <td>7</td> <td>507</td> <td>72.5</td> </tr> <tr> <td>8</td> <td>556</td> <td>69.5</td> </tr> <tr> <td>9</td> <td>603</td> <td>67.0</td> </tr> <tr> <td>10</td> <td>722</td> <td>72.2</td> </tr> </table>

From this table it appears, that the lamp here used burned to the greatest advantage when made to give a light equal to eight or nine of the wax candles; and from other experiments of the like nature, the proportions above hinted at may be taken as follows:

An oil argand burner one-third inch diameter, is most advantageously employed when giving a light equal to about 3 wax candles. One 11-20th inch diameter, about 5 Do. One 7-10th (being that above particularized), about 9 Do.

It was to be expected that something similar to the above would occur with regard to the combustion of gas, and this we have seen fully established by experiments made in 1807 and later years, and without any knowledge of what Count Rumford had done.

An argand gas burner, about three-fourths of an inch diameter, when regulated so as to give light equal to one mould candle of six to the pound, consumed

<table> <tr> <th>Cubic feet of Gas, per hour</th> <th>when equal to 4 candles,</th> <th>6 do.</th> <th>8 do.</th> <th>10 do.</th> <th>Cubic feet per Candle,</th> <th>being 1.43</th> <th>0.49</th> <th>0.40</th> <th>0.37</th> <th>0.31</th> </tr> </table>

In other experiments the consumption did not exceed one-fourth of a cubic foot per hour for each candle, when the flames were as large as the burners would admit of without producing smoke.

General Arrangement of a Gas Apparatus.

As the general plan of gas-lighting establishments will be affected by local circumstances which cannot here be considered, the disposition and arrangement of the different parts is a subject on which much cannot be said. Plate LXXXIV. exhibits a plan and elevation which, where the situation will admit, will be found as convenient as any. The retorts, b b, are placed round a conical chimney, a a, into which all their flames enter, and in its lower part the ashes and cin- ders are collected from the different fires, and taken out from time to time by an entrance from the circular tunnel, f f. This tunnel is furnished with apertures above, corresponding to the number of the retorts, and through which the coke is suffered to descend when discharged. The retorts are covered with a conical roof, under which are a number of small openings to take off any dust, smoke, &c. which arises; exterior to this roof (which covers the part c, where the retorts are charged and discharged) is another over e, less elevated, leaving a circular space d, to admit light; under this may be deposited coals, &c.

The gas and other products of distillation are conveyed, by means of the pipe g, into the tar reservoir p p; over which the condenser h, and purifier i i, are placed, and from this last the gas passes by the pipe k, to the gasometers m m, through the tubes l l (in the manner represented in Plate LXXXIII. fig. 6), and from these again at n, for distribution and combustion when required.

The apparatus here delineated (on a scale of 20 feet to the inch) contains twenty-one retorts of the dimensions shown in Plate LXXXII. fig. 8; two gasometers are represented together capable of containing 50,000 cubic feet of gas; and in case of repairs, &c. being wanted, it will, in general, be found more convenient to have, instead of one gasometer of the full capacity required, two or more of a lesser size connected with the apparatus; and it may frequently happen that these can be placed at a distance from each other, particularly in lighting a town of any considerable magnitude, where such distribution will be attended with the advantages of more perfectly equalizing the pressure on the gas, and of lessening materially the size of the mains necessary for conveyance, as these distant gasometers can be filled during the period when light is not required, and the feeding mains answer the purpose of conveying the gas partly back again for combustion.

Preparation of Oil-Gas.

In Nicholson's Journal for 1805, Dr Henry has given an account of his experiments on the gases obtained by the destructive distillation of oil and other substances; but no apparatus for conveniently effecting the decomposition of oil on a large scale appears to have been constructed for many years afterwards. In 1815 Mr John Taylor obtained a patent for a mode of producing gas from bones and other animal matters; and the principle of action of the oil-gas machines, now manufactured by him, will be understood from fig. 9, Plate LXXXIII.: a a a is a metallic or other tube placed in a furnace capable keeping it red hot; b, the fire place; c, a small close box or cistern containing oil; e, a pipe leading from this box to one end of the tube a, and having a regulating cock thereon; f, another pipe joining the opposite end of the fire-tube, and also joining the oil-cistern at its upper side; g, a pipe to convey away the gas when formed, and d, another pipe with funnel attached for admitting a supply of oil from time to time.

The fire-tube being heated to a moderate red heat, oil is admitted by means of the cock, e, and in its passage through the heated tube is decomposed, or partially so, and makes its escape by the pipe, f, back again into the oil-cistern in a gaseous, or vaporous state, where such particles of the oil, as have merely been volatilized, are again condensed, and the permanent gas passes forward through the pipe, g, to a gasometer, or otherwise as required.

To render this apparatus more complete and convenient, the ingenious patentee has arranged it, for general use, nearly in the manner and form represented in figs. 10, 11, 12, which are different views of the same thing; the fire-tube here is bent in the shape of the letter U, as shown at a a a a; b, the grate; the oil is admitted at one extremity by the pipe, e e (having a regulating cock upon it), from the oil cistern, c, and the gas taken off from the other by the pipe, f f, as in fig. 9, above described.

The vessel, c, has a funnel, d, attached to it for the purpose of supplying oil when required. The pipe, f, which conveys away the gas (and any vapour which may be formed from the admission of a greater quantity of oil than can be decomposed in its passage through the fire-tube), is connected to a close vessel, h, which is surrounded with water contained in a cistern, i i; and this cistern also contains a spiral-tube, or worm, k k, the lower end of it connecting with the vessel, h, and its upper end with a descending pipe, l. The vessel, h, and worm, k, being immersed in cold water, serve for the purpose of condensing any oil that may arise in a merely volatilized state; and this oil being collected in the bottom of the vessel, is allowed to descend again into the cistern, c, by a tube connected therewith.

The gas, though now separated from the vapour in a great degree, is, in order to render it more perfectly pure, conveyed by the pipe, l, above mentioned, into an air-tight chest, m m, in which water is contained up to the level represented; n is an inclined partition fixed across the chest, having diagonal ribs attached to its under side, so that when gas is forced in beneath it through the pipe, l, it circulates underneath the partition in a zig-zag direction, gradually ascending till it escapes at the upper end, and rising through the water, is taken off at g, to a gasometer (such as has been already described) for use.

In order to increase the effect of the fire-tubes, they are loosely filled with different substances, the better to cause the decomposition of the oil. Pieces of brick, or coke, answer this purpose; and as these require to be taken out and renewed from time to time, there are, at q q, two openings, with air-tight covers, for allowing this to be effected, and by means of which the tubes can also be cleaned by scraping out such carbonaceous matter as adheres to their inner parts: p p p are stoppers, also for the purpose of allowing the pipes, e and f, to be cleaned in the like manner. Such an apparatus as is here represented (to a scale of one-third of an inch to the foot) will yield 100 to 120 cubic feet of gas per hour. Illuminating Powers of Coal and Oil-Gases.

Comparative powers of Coal and Oil-Gases.

To compare the expence of oil-gas with that obtained from coal, a knowledge of the comparative illuminating powers of equal bulks is necessary. It is stated (Quarterly Journal of Science, &c. No. XIV.), that one cubic foot of oil-gas will yield as much light as four of coal-gas; but, in another part of the same article, that the proportion is only five to nine. Mr Brande (Annals of Philosophy, December 1819) gives one to two as the proportional value of the two gases: our own experiments give seven to thirteen. Much discrepancy may arise from the way in which such experiments are conducted: an argand burner, which will, when burning coal-gas, give, with the greatest advantage, a light equal to any number of candles, should, when used with oil-gas, be adjusted to emit a considerably greater quantity of light, in order to burn that gas in the most economical manner. There is always a portion of blue or dark coloured flame adjoining the burner; and to make the comparison fair, this ought to bear an equal proportion to the white flame in both cases; and though some attention was paid to this circumstance in making our experiments, we have little difficulty in believing that the result would have been somewhat more favourable to the oil-gas, had the proportions of white and blue flame been more accurately adhered to; and we therefore incline to consider Mr Brande's numbers of one to two as the most correct.

The volume of gas which a given quantity of whale-oil yields has been variously stated, at from 80 to 110 cubic feet per gallon, and the quality of the oil, and mode of distillation, may partly account for the difference. We have not been able to obtain more than 95 to 98; but as some waste took place, in the portion which was volatilized not being wholly condensed and collected, it is probable that 100 may be taken as the number of cubic feet which one wine gallon of good whale-oil will produce.

Gas from Coal Tar.

Attempts have been made to decompose coal tar in order to obtain the gaseous products; and this may be effected without much difficulty, by an apparatus nearly similar to that used for decomposing oil, and by other means. But it does not appear from the experiments which have been made, that the gas produced is well fitted for the purposes of illumination; probably from a great quantity of pure hydrogen being mixed with the carbureted hydrogen gas formed; or, if Mr Brande's theory of the non-existence of the latter gas be correct (Annals of Philosophy, December 1819), because the olefiant gas occurs in extremely minute quantities, compared with the quantity generated during the distillation of coal.

When atmospheric air is mixed with about one-eighth part of its bulk of coal gas, and set on fire, it explodes; and, if in a confined situation, may do serious mischief. Accidents have occurred from these explosions, which originate in ignorance, mischief, or carelessness. The offensive odour emitted both by oil and coal gases unburnt, is a very sufficient warning of their escape; and the propriety of Gas-Lights having every part of a gas apparatus perfectly tight, and free from leaks, is a matter of importance, not only as regarding safety and the prevention of this nuisance, but also the actual waste and loss of a valuable commodity. A leak from a hole one-twentieth of an inch diameter would, under the usual pressure, in the course of one year, waste coal gas to the value of L. 10 and upwards; and, supposing it to be emitting gas into a chamber of ten feet cube, it would require from two to three days to render the air of it explosive, and this only on the supposition that the apartment was nearly air-tight. Any ordinary escape of gas into a room, having a door, window, and fire-place, where a circulation of air is constantly going on, could never cause an explosion, though explosions have occurred, from its getting, in the first instance, into confined adjoining places, as closets, cup-boards, arched vaults, or the like. In these situations, when the smell of gas is perceived, ventilation should be resorted to, by opening the doors, &c. and lights should be kept away from them, until the smell ceases to be offensive.

Gas from Coal Tar.

Explosions and Accidents.

Economy of Gas-Lights.

We now come to treat of the expence of light obtained from coal and oil gases, and their comparative cost, compared with that from oil and tallow, as commonly consumed in lamps and candles. The fluctuations of price to which these commodities are liable, and the varying expence in different places of buildings, and other things required in forming a gas-work, must, of course, render any statement of comparison that can be given inapplicable to the forming of any other than a very general result.

The expence of such an apparatus, as is represented in Plate LXXXIV. may be taken as follows:

<table> <tr> <th>Twenty-one retorts, with all their appendages, tar-vault, condensing and purifying apparatus, and buildings, belonging to the same.</th> <th>L. 5,500</th> </tr> <tr> <th>Two gasometers, with their cisterns, and all apparatus, and buildings.</th> <th>5,200</th> </tr> <tr> <th>The cost of the main pipes, with their stop-valves, water-receivers, &c. for distributing the gas, must depend entirely upon circumstances which cannot be considered here. In lighting towns, the amount has, in some cases, equalled, or somewhat exceeded that of the rest of the apparatus. Say then,</th> <th>10,300</th> </tr> <tr> <th>Total expence,</th> <th>L. 21,000</th> </tr> </table>

This apparatus will be capable of supplying about 50,000 cubic feet of gas daily, using sixteen or seventeen of the retorts; the remainder being kept as a reserve in case of accidents to the others from cracks, burning, or wearing out. And though such a consumption of gas should be necessary in the depth of winter, yet it will be found, that, upon an average for the year, a daily supply of about half the quantity will suffice in the way in which it is G Lights. generally consumed in lighting towns. This apparatus may, therefore, be considered as capable of giving 25,000 cubic feet of gas each day in the year.

To procure this quantity, 48 cwt. of cannel or coal fitted for the purpose will be required, and which, in the coal districts, may be calculated at 20s. per ton, giving for the annual charge about L. 880 Common coal for fuel, say half the weight of the above, and at half the price, 220 Lime and water for purifying the gas, 270 Management, wages, and sundry charges, 1,090 Annual renewal of sixteen or seventeen retorts, 230 Two and a half per cent. on the amount of main pipes, &c. 260 Ten per cent. on the amount of the other parts of the apparatus to cover repairs and ordinary wear and tear, 1,070

Annual expenditure, L. 4,020

Which amounts to L. 11 per day as the cost of 25,000 cubic feet of gas, or about 8s. 10d. for the cost of each 1000 cubic feet, exclusive of interest on capital; with that added, it will amount to 11s. 2d., and as 20 cubic feet of gas will give the same light that 1 lb. of tallow does, the cost of it will be

\[ \frac{(11s.\ 2d.\times20)}{1000} = 2\frac{3}{4}\text{d. barely.} \]

An apparatus capable of supplying an equal quantity of light by means of oil gas, would in point of expence amount to nearly as follows:

Retorts with all their apparatus, condensing and washing vessels, and buildings for the same, L. 3,700 Gasometers, &c. of half the capacity of the former, 3,500 Main pipes, &c. the length supposed the same as before, but the capacity reduced one half, 7,700

Total, L. 14,900

The quantity of gas daily consumed will average 12,500 cubic feet, or half the bulk which could be required of coal gas.

To produce this, 125 gallons of oil are necessary, and valuing the same at L. 32 per tun, the annual charge will be about L. 5,780 Common coal for fuel, and water, 220 Management, wages, and sundry charges, 820 Annual renewal of retorts, 100 \( \frac{1}{2} \) per cent. on main pipes, &c. 190 10 per cent. on the other parts, 720

Annual expenditure, L. 7,830

Or about 4\(\frac{1}{2}\)d. for a light equal to what 1 lb. of tallow would give; and if interest on capital is included, it will amount to about 4\(\frac{3}{4}\)d. being, compared with the cost of coal gas-light, nearly as ten to six.

In the above calculation for the expence of coal gas, no mention is made of the coke, tar, oils, and ammonia produced. The value of the coke depends much upon the nature of the coal employed; that obtained from such as the Newcastle coal answers well for house fires, drying kilns, stoves, &c.; but the Cannel coal, which is used for making gas to a great extent in many parts of the kingdom, gives a very inferior coke, of frequently not more than 1-5th to 1-6th the value of the coal which produced it. The tar, when boiled and mixed with drying oil and other substances, forms a paint which may be used for common purposes; it may also be converted into pitch, and by burning it in close vessels, a species of lamp-black is produced. On the whole, this and the other liquid products have, however, not been considered as of much value, and the getting rid of them and of the refuse lime, which has been used in purifying the gas, is often attended with an expence which their own value, and that of the charcoal, will not more than compensate.

Though the expence of lighting by gas from oil appears, on a large scale, not to be much less than double that of coal gas, the same great disproportion will not altogether hold for very limited quantities of light, where the charge for an attendant forms a considerable part of the current expenditure. A coal gas apparatus, however small, will, when in work, require the almost constant attendance of a person to manage the fire, to charge and discharge the retort, to renew the lime or other substance used for purification, and to remove that which has done its office, also to empty the tar reservoir, &c. In the other apparatus, when the oil reservoir is filled and once set to work, it requires no other attendance for a number of hours, than the keeping of the fire in order; and the production of gas can be continued at pleasure, or stopped by the mere turning of a cock, and the nuisances accompanying the formation and removal of tar, ammoniacal liquor, and lime refuse, are entirely avoided.

An argand oil lamp with a burner three-fourths of an inch diameter, we have found to consume 406 grains of the best spermaceti oil in one hour, when giving the light of 3\(\frac{1}{4}\) candles of the size above specified. Five thousand grains of oil will, therefore, give the same quantity of light that 1 lb. of tallow does, and valuing it at 5s. 6d. per gallon, the cost will be, with an allowance for wicks and trouble of trimming, about 6\(\frac{1}{2}\)d.

The comparative expence of light from the different substances mentioned below will then be as follows:

<table> <tr> <th>Valuing the quantity which 1 lb. of tallow gives in candles at</th> <th>s.</th> <th>d.</th> </tr> <tr> <td>An equal quantity of light from spermaceti oil consumed in an argand lamp will be</td> <td>0</td> <td>6\(\frac{1}{2}\)</td> </tr> <tr> <td>A ditto ditto from whale oil gas,</td> <td>0</td> <td>4\(\frac{1}{2}\)</td> </tr> <tr> <td>A ditto ditto from coal gas,</td> <td>0</td> <td>2\(\frac{3}{4}\)</td> </tr> </table>

It would have been desirable to have been able to give a comparative table of the actual charges made for supplying gas-lights in some of the principal towns of the kingdom; but unless some stand- Gas-Lights and size of the burner or burners employed was fixed, any thing of this kind would be nearly impracticable. In some places the Argand burners used are of three or four different sorts, and named No. 1, No. 2, &c. the smallest being distinguished by the least number; the reverse occurs in other places, where the highest number is used to designate the least. The number and size of the perforations vary considerably; as likewise does the length to which the flames are allowed to be burnt; and variations also take place from time to time in some towns lighted by gas, which circumstance alone would render any attempt at a comparison of the rates charged of doubtful utility. (F.F.F.)

GENOVESI (Anthony), an eminent Italian Writer, was born on the 1st of November 1712, at Castiglione, near Salerno, in the kingdom of Naples. From his earliest years he showed an uncommon capacity; but after receiving such education as his native village could afford, his father obliged him to devote himself to the study of scholastic theology, with a view to the ecclesiastical profession. In a short time he distinguished himself as a proficient in dialectics; but having formed an attachment to a young woman, he was on the point of sacrificing to her all his professional prospects, when his father, who had obtained a knowledge of the circumstance, removed him to another village, where he found a priest who diverted his attention to different objects. Having been afterwards excommunicated by the Archbishop of Conza for acting a part in a comedy, he returned to Castiglione; where, having found his mistress married, he reassumed the cassock, and took priest's orders at Salerno in 1736. Here he soon distinguished himself so much by his talents and knowledge, that the Archbishop of this town confided to him the Chair of Eloquence. At this period Genovesi was a mere school theologian; but a friend of his, a young ecclesiastic, now made him aware, that there were sources of knowledge beyond the scholastic sphere, more extensive, more interesting, and more real, than those to which he had hitherto applied. Genovesi entered into this new intellectual world by the perusal of some romances; from these he proceeded to the study of history; and stepping from one subject to another, he finally applied himself to the study of modern philosophy, and read with attention the works of Leibnitz and Locke. In the hope of acquiring still farther information, he repaired to the capital; and as he did not possess the necessary means of maintaining himself there, he resolved to exercise the profession of an advocate; but becoming disgusted with the details of practice, he soon sacrificed his hopes of fortune to the pleasures of study. He improved his knowledge of the Greek, and of several of the modern languages; attended all the most celebrated professors of the University of Naples; and soon perceived the imperfections of the existing system of public instruction.

Notwithstanding the progress which philosophy had made in other countries, the kingdom of Naples was, at that period, in a state almost retrograde, or, at least, stationary. Genovesi felt this, and he resolved to accomplish certain reforms in the system of education, with a view to the amelioration of the condition of his countrymen. None ever succeeded better in this generous design. Although there existed at Naples a University, celebrated for the learning of several of its Professors, the pupils had long been accustomed to carry on their studies in private schools. Genovesi having conceived the design of opening one of these seminaries, he procured the appointment of extraordinary Professor of Metaphysics in the University, in order that he might appear before the public in a known character. He had formed peculiar methods of his own in all the faculties which constitute the philosophical course; and his first Essays induced him to publish his Elements of Metaphysics, of which the first volume appeared in 1743; and afterwards, in 1745, his System of Logic.

In these two works, he made ample use of the doctrines of Bacon, Descartes, Leibnitz, and Locke; and, having substituted philosophical doubt for implicit belief; the observation of nature for the speculations of the schools, and reason for authority,—this was sufficient to cause him to be denounced as an infidel, or at least as an irreligious person, by those who still adhered to the scholastic methods. He would probably have fallen a sacrifice to these prejudices, had he not been supported by Galiani, Archbishop of Tarentum, Grand Almoner of the King, and Grand Master of the University; but, notwithstanding this protection, he experienced some trouble and difficulty in obtaining the professorship of Moral Philosophy; and he was disappointed in an attempt to procure the chair of Theology.

The unjust and obstinate hostility which he suffered on account of his theological works diverted him, for some time, from this dangerous path of inquiry, and brought him back to that of philosophy. He published a continuation of his Elements of Metaphysics, but, with every new volume he continued to experience the censures and opposition of the partisans of the scholastic routine. Among these were the Cardinal Spinelli, Archbishop of Naples, and an Abbé Magli, whom Genovesi covered with ridicule in his work entitled Lettere a un Amico Provinciale. In spite of these continual jarrings, Genovesi obtained the approbation and esteem of Pope Benedict XIV., of several Cardinals, and of most of the learned men who at that period flourished in Italy. Of this number was Intieri, a Florentine, who having spent a long time at Naples, became much attached to that country. This man, as distinguished for his philanthropical qualities, as for the extent and solidity of his acquirements, was still more estimable on account of the use which he made of his fortune. It is to him that Italy is indebted for her first Chair of Political Economy; he founded it, at his own expence, with the sanction of government, in the University of Naples, under three conditions, viz. that the lectures should be given in