Obrazy na stronie


MiscellaneousAnswers to Correspondents.


Nov. 17, 1865.

been determined by Professor W. H. Miller, of Cambridge. A set of six cylindrical cells of Groves' battery were
The truth is, that the mineral in question was submitted thus, with the same materials, amalgamated, equipped,
to this eminent authority, but Professor Miller was unable and primed for action in a quarter of an hour.
to separate a crystal from the aggregated masses in a con- No friction is needed ; the plates should be well drained
dition fit for accurate measurement. Professor Church's from excess of mercury, lest they become brittle, though
own observations had led him to conclude that the crys- this danger is lessened by the rapidity of the process. The
talline form of the mineral was oblique, but his observa- rationale of my preference for HCl and HgCl, is sufficiently
tions having been made with the inferior instrument, obvious.

I am, &c. B. W. GIBSONE, F.C.S. the microscopic goniometer, may almost be said to require

November 7.
confirmation--a duty which Professor Maskelyne, at the
meeting, volunteered to undertake.

The hydrated phosphate of calcium and aluminium,
although containing the same amount (12 per cent.) of
water, is believed by Mr. Church to differ from the mineral
described by M. Damour as occurring in the diamor:d selected for the ensuing year :-President.--Major-Gen. Ed,

The Royal Society.—The following are the officers sands of Bahia. Lastly, with respect to the double arseniate of copper Miller, M.D., LL.D. Secretaries.--William Sharpey, M.D.,

Sabine, R.A., D.C.L., LL.D. Treasurer.-William Allen and lead, it should have been described, not as a variety of LL.D., George Gabriel Stokes, Esq., M.A., D.C.L. olivenite, but as a distinct species belonging to the oliven- Foreign Secretary.- Professor William Hallows Miller, ite group.

I am, &c.

November 13.

M.A. Other Members of the Council.-John Frederic
Bateman, Esq., Lionel Smith Beale, Esq., M.B., William

Bowman, Esq., Commander F. J. Owen Evans, R.N.,
The Past and Present History of Alum.

Edward Frankland, Esq., Ph.D., Francis Galton, Esq., To the Editor of the CHEMICAL NEWS,

John Peter Gassiott, Esq., John Edward Gray, Esq., Sir,-In your last issue I find mention of my “Dictionary Ph.D.; l'homas Archer Hirst, Esq., Ph.D., Sir Henry of Chemistry" by Mr. J. Carter Bell, F.C.S., relative to Holland, Bart., M.D., D.C.L., William Odling, Esq., the article “ Alum." Mr. Bell remarks :-“This is a most M.B., Sir John Rennie, Knt., Professor Warington W. unfair description of such important alum works as Mr. Smyth, William Spottiswoode, Esq., M.A., Paul E. Spence's are, and I am surprised to find such a statement Count de Strzlecki, C.B., D.C.L., Vice-Chancellor Sir in such a compendious dictionary as Dr. Muspratt's pro- W. P. Wood, D.C.L. fesses to be." Your correspondent, Mr. Bell, applies the

Reaction of Metallic Thallium on a Few word professes to a book that all the first savans of the solutions of Metals.-Thallium immersed in solutions world have eulogised, and which Baron Dumas, of Paris, of sulphate, nitrate, and acetate of copper, deposited in calls “the great chemical work of the age." As it is the first and only time the information in the Dictionary AgONO, deposited silver ; thallium in Auoso, deposited

flakes (similar to iron) metallic copper ; thallium in has been called into question, I feel bound to notice Mr. gold; thallium in Hgoso, (sulphate of the red oxide) Bell's statement, and I beg leave to say that at the time each monograph appeared, it contained " a complete ex- deposited mercury; thallium in PbOĀ deposited lead. position of the state of the chemical manufactures, with The gold appeared in flakes, partly floating and partly at the latest and most improved processes” (vide Preface). bottom; mercury in small globules ; lead as a crystallised Your readers must bear in mind “ Alum" was written

mass on top of the thallium-very similar to thallium on nearly fourteen years since !

zinc. When thallium is put into a solution of the nitrate Is it likely, Sir, that “ Alum” should be the only of cobalt, the metal is covered with a blue coating, which incomplete article in the book? Why Mr. Bell has from it becoming green on exposure to the air, appears to thought fit now, at this late date, to find fault with it is be similar to that basic salts of cobalt precipitate which is best known to himself. If I should re-write “ Alum” for thrown down by KO.-Walter C. Reid. a “next edition of the Dictionary, a better description will Clay and Glycerine for Modelling.- We read be given," if requisite. I am, &c.

in Cosmos that a mixture of clay and glycerine, which SueridaN MUSPRATT, M.D., Prof. of Chemistry. keeps its plasticity for any length of time at all temperaCollege of Chomistry, November 13.

tures, has been found very useful by modellers. The clay

must be well dried before it is mixed with the glycerine. Ready Mode of Amalgamating Zinc Plates.

It is said that the mixture can be used in place of wax for
To the Editor of the CHEMICAL News.

the most delicate work.
SIR.-I venture to send you a method of almost instan-
taneously amalgamating corroded zinc battery plates,

which occurred to me recently, after some twenty years'
trial of different plans; perhaps economy of time in even
humble matters of detail may be worth record where the All Editorial Communications are to be addressed to the EDITOR,
process is of repeated occurrence.

and Advertisements and Business Communications to the PUBLISHER, at The following treatment in the case of thickly oxidised letters for the Editor must be so marked.

the Ofhce, 1, Wine Office Court, Fleet Street, London, E.C. Private plates will yield in speed and effectiveness to few :- Place in a flat dish two ounces of common hydrochloric acid, one drachm of a saturated solution of bichloride of adopt the views of the writers,

In publishing letters from our Correspondents we do not thereby

Our intention to give both sides of a mercury (corrosive sublimate), and half an ounce of the question will frequently oblige us to publish opinions with which we latter metal ; lay the zinc, without previous scouring, in do not agree. the liquid mixture, and gently smear the mercury over surface of the plate with a toothbrush ; the mercury will Dr. Muspratt.-Received, with enclosures. readily and thoroughly adhere to each portion of the sur

Jeremias.--We must decline our correspondent's last communication. face as the oxide is rapidly dissolved by the HCl.

Mr. Walke'. -The patents have come to hand.

Ninety-nine. -Both errors are so obvious as to correct themselves, As a means of comparing speed, in seventy seconds I As regards the second pointed out, it must have occurred to every completely coated inside and out a cylindrical plate of reader but our acute correspondent that the decimal point was in the forty square inch surface, whose interior was rather in- wrong place, and that it should have been '56.

Books Received, "Pereira's Manual of Materia Medica," edited by accessible and very corroded.

Dr. Farre.

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Detection of Chlorine, 8c., by Spectrum Analysis. Nov, 34, 1865.


be added to the solution. The greater part of the iodine

and bromine will be found in the precipitate, which may CHEMISTRY.

be tested as before described.

The following results will serve as an illustration of On the Application of Spectrum Analysis to the Detec- the accuracy and precision of the process. To a pound of

tion of Chlorine, Bromine, and Iodine, by ALEXANDER common salt which contained no bromine five milliMITSCHERLICH*.

grammes of bromide of sodium were added, and to the The diffculty of recognising small amounts of chlorine,

solution one decigramme of nitrate of silver. The prebromine, and

iodine in a mixture of haloid salts is weií cipitate was tested in the way just described, and after known; and it is found impossible to detect mere traces some time, the spectrum of bromide of copper was dis

the spectrum of chloride of copper had been observed for of these bodies in such mixtures by any hitherto tinctly visible for five minutes. A further addition of known method. I have, however, discovered a means of nitrate of silver to the solution gave a precipitate which recognising the smallest amounts of these substances by showed the spectrum for six minutes. the use of spectrum apparatus. The haloid salts of copper are the most difficult to de equally conclusive results, and proved

that a ten-millionth

Similar experiments made with iodine compounds gave compose by heat, and they are therefore to be preferred part of iodine or bromine may be detected in chloride of for spectrum investigations, which are best made in the

sodium. following way: The substance to be examined, well

The residue of six and a half pounds of sea water taken dried, is intimately mixed with half its weight of sul- off Heligoland (precipitated with silver ? ) showed the phate of ammonia and one-tenth its weight of oxide of spectrum of the bromide for seven minutes. Iodine could copper. This mixture is placed in a globular enlarge- not be recognised, probably because the quantity of ment of a combustion-tube, one end of which is connected water was too small. with a hydrogen gasometer, the opposite end being open. A stream of hydrogen is passed through the tube, and

A small quantity of water from the Dead Sea showed heat gradually applied to the mixture. The hydrogen liquor from some salt works showed much bromine, but

a large proportion of bromine, but no iodine. The mother being ignited, the first appearance seen in the spectrum

no iodine, apparatus is a brightness in the green in which, however, no definite spectrum can be perceived ; but after-haloids a tube with two bulbs must be connected with

Where organic matters are to be examined for the wards the spectrum of the haloid salt of copper is dis- the hydrogen apparatus. The bulb nearest the flame is tinctly visible. When present in small amount the chlorine compound is placed in the other. Both being heated, the products

filled with oxide of copper only, and the organic matter is best recognised by the lines at 105 and 109, and by of the heated organic matter over the oxide of copper the brightness near 85 and 87; the bromine compound reduced by the hydrogen in the second bulb.

In is detected by the brightness at 85, 884, and 92; and this way the smallest amount of chlorine, bromine, or iodide of copper by the brilliancy at 96, 99, and 1024. By this method, and without further trouble, è per a large excess of the other.

iodine may be recognised ; and, indeed, traces of one in cent. chlorine, 1 per cent, bromine, and 1 per cent. of iodine are easily recognised, and a practised observer something like quantitative results by noting the time

The author thought it might be possible to arrive at may detect

much smaller quantities. 'One disadvantage which the several copper compounds took to volatilise ; of this method is that at a high temperature the sulphate but he found it impossible to avoid large sources of error. of ammonia decomposes, and the spectrum of ammonia, which renders the others obscure, is obtained. With some compounds the addition of this salt is unnecessary, as in the cases of the chlorides of silver and mercury.

Researches on the Influence of the Electro-negative The use of sulphate of ammonia, indeed, renders it Elements on the Spectra of Metals, by M. E. Diacon. I difficult to recognise the haloids when mixed with each The method of analysis founded by Kirchhoff and other in very small proportions, and it is better to pre- Bunsen on spectrum observations have given results so cipitate the haloids first by a silver salt, mix the dried remarkable that its utility in chemical researches is not precipitate intimately mixed with twice its weight of to be contested. Nevertheless, the principle on which oxide of copper, and employ this mixture in the hydrogen it rests is only true under certain determined conditions. apparatus before described. By this method as little as From my own observations and those of A. MitscherLoth per cent. of chlorine, įth per cent. of bromine, and lich it seems certain that the different compounds of a įth per cent. of iodine in the silver precipitate can be metal do not exhibit an identical spectrum, and in this recognised.

paper I propose to collect the experiments which show The spectra of the haloid salts appear consecutively, the influence of the electro-negative element on the rathat of the chloride first, then that of the bromide, and diations emitted by different salts of the same metal. lastly that of the iodide of copper. Their appearance In a series of spectrum researches made on a great in this order depends on the different volatility of these number of mineral waters, I remarked some appearances salts. Chloride of copper volatilises considerably below which led me to study attentively the spectrum of barium a red hoat, the bromide somewhere near redness, and the in the presence of salts of lime or strontia. Under such iodide at a low red heat. The slower the volatilisation conditions I not only observed faint lines not indicated is conducted, the more certain are the results of the for either of these metals, but was further struck by analysis.

the remarkable change which the spectrum of barium When only traces of iodine and bromine compounds underwent, when a pearl of chloride of calcium was are present in a large excess of a chlorine compound, introduced into the same flame. about the tenth of a gramme of nitrate of silver should This phenomenon, consisting in the much greater bril. Abstract from Poggendor:l"s Annalen, No. Several Pialali salts are

liancy acquired by certain green lines of barium, appeared † Drawings of the spectrum given by the several given with Poggendori': Annalen, No. 4, 1864.

Abridged from Annales de Chimie et de Physique, Sept., 1865. You. XII. No, 312NOVEMBER 24, 1865.


Influence of Electro-negative Elements on the Spectra of Metals. {CHEMICAL NEWS,

Nor. 24, 1865.

to me so strange at the time—when it was fully ad- produced by the decomposition of the salts. The same mitted that in the case of a mixture the spectra were is the case with the chiorides of platinum and silver. simply superposed without influencing each other—that Chloride of gold, however, gives a well-defined spectrum I called in other observers. The observation of a green formed of a series of beautiful green lines. With chlo band, pale and ill-defined, which the spectrum of calcium ride of palladium bright blue lines are seen, but only sometimes presents, and which coincides with the second for a very short time. of the green lines of barium, led me to ascribe it to Chloride of manganese gives a well-defined spectrum, absorption ; the diminished intensity of this line might like that of the salts of the metal in the gas flame. have produced the sensation of greater brilliancy in the Chloride of iron shows a great number of lines bathed other lines. But all the experiments only gave me nega- by the light due to the incandescence of solid particles tive results; the phenomenon was only produced when carried by the vapours. The chlorides of cobalt and the two pearls were in the same flame, and very near to nickel present the same phenomena, but with less inteneach other. Hence it seemed necessary to admit that sity, so that, notwithstanding the great number of lines the two bodies might act on each other and modify which constitute them, it is easy to distinguish the their spectra.

spectra of the two salts, the red lines being more numeThe appearances noticed above not appearing when rous in nickel, the yellowish-green lines more numerous even volatile compounds of calcium were substituted for with cobalt. the chloride, I soon became certain that they did not Uranium, cerium, chromium, glucinum, aluminium, belong to the metals themselves. There remained then and magnesium gave only negative results ; to obtain the action which the chloride of calcium or the chlorine the spectra of these metals it is necessary to experiment disengaged during the rapid oxidation of the metal in with anhydrous chlorides. the flame might have on the barium. Experiments Experiments made in the way described showed that which I made with quite a different object set the ques- certain chlorides decomposed less rapidly in a chlorintion at rest.

ising flame, and, therefore, gave spectra; but the experiMany metals whose chlorides are volatile give no ment with chloride of barium led to results of special spectra in a Bunsen's flame. It is reasonable to believe interest. That salt gave a spectrum quite different that the rapid decomposition these chlorides undergo in from that of the metal; the large number of lines which an oxidising flame is the principal cause of this, and that characterise the latter had disappeared, and were reit would be otherwise, with many of them at least, if placed by a small number of very bright lines. I immethe temperature sufficed. This I hoped to realise by diately examined the chloride of strontia, and was no placing them in a chlorinising flame obtained by the less surprised at perceiving neither the blue nor the combustion of hydrogen in chlorine. The apparatus orange line, seen so brilliantly in the gas flame. The adopted after some trials is the following :- A box, spectrum of chloride of calcium showed differences no blackened in the inside, 60 c.c. high, and 15 c.c. wide less striking and real. With lithium nothing peculiar and deep, receives the blowpipe; two openings in the was seen. The chlorides of sodium and potassium sides, to be closed at will by glass, serve one for the appeared not to give spectra. Chloride of thallium observations, the other for the introduction of the appeared to present no change, even in the intensity of matters to be experimented upon. An inclined tile of the characteristic green line. refractory earth forms the roof of the box, and directs Modifications so profound can only be explained by the products of combustion into a second box partly admitting that each compound has a peculiar spectrum, superposed, and of about the same dimensions as the but the specific nature of metallic spectra has been 80 first. This second box contains a number of laths placed clearly laid down in principle by Bunsen and Kirchhoff horizontally, and carrying slaked lime, so as to leave that it seemed necessary to support by new experiments a free passage for the gas. A long wooden exit tube a fact so contrary to the results obtained by these authors. placed below the laths carries the gas not absorbed by If chlorides have peculiar spectra, it must also be the the lime into the chimney, a gas lamp above the opening case with bromides and iodides. It was hoped that of the tube acting as an aspirator. The rest of the similar experiments to those made with chlorides would apparatus is composed of a blowpipe and two gasome- demonstrate this ; but attempts to obtain a flame with ters placed outside the laboratory, one of glass for chlo- bromine and iodine and hydrogen did not succeed. rine the other for hydrogen. The gases are conducted The author now fell back on the first experiment by lead pipes, and afterwards by caoutchouc tubes to the mentioned in this paper. The appearances observed blowpipe ; the chlorine in a small tube placed within a when baryta was heated in the presence of a pearl of larger, which carries the hydrogen.

chloride of calcium he assured himself were due to the The easy reducibility of chloride of platinum allows superposition of the spectra of oxide and of chloride of wires of this metal to be used as supports. The matters barium. The rapid decomposition of the chloride of experimented upon are placed in the interior of the calcium surrounding the baryta with an atmosphere of flame, so that they may be in the presence of an excess of chlorine chlorinised a part, and, consequently, determined chlorine, and beyond the influence of external air. the appearance of lines characteristic of chloride of Lastly, the spectroscope is directed to that part of the barium. A pearl of chloride of barium by itself preflame situated immediately above the wire support. sented the saine appearances, but with less intensity at Under the e circumstances a great number of metals give the moment it was introduced into the gas flame. spectra of very variable persistence.

A comparative study of the spectra given by chlorides Chloride of copper gives a magnificent spectrum ; that in chlorine, and by oxides in a blow-pipe flame fed with of chloride of bismuth is also very brilliant. Chloride air or even pure oxygen, soon demonstrated that the lines of lead shows a great number of brilliant lines, the positions of which seem to differ from those of the metal memoir of M. Niitscherlich (see CHEMICAL NEWS, vol. vil, p. 99) and

$ At this stage of his investigation the author met with the in the gas flame. With tin, and more especially with repeated that gentleman's experiment, but came to the conclusion antimony, it is often impossible to distinguish the lines that the spectra obtained by his method were simply those of the which characterise them, on account of the diffused light on terly and that the lines specially belonging to the chlorides escaped CHEMICAL INSEKTE }

Society of Arts.




appear at the moment a chloride is introduced into a gas supply and an outlet connected with the burner. an oxidising flame are due to the superposition of two The gas in its course passes over the surface of the hydrospectra. The experiment succeeds best with the alkaline carbons. Being above the flame, the vessel and its conearthy metals, and with copper and bismuth. With the tents become heated, and part of the latter is converted two latter and with calcium the spectrum of the chloride into vapour, which the passing gas carries with it to the predominates.

burners to enrich the flame. Two consequences result from these experiments

The following are the advantages which Mr. Bowditch's 1. The spectra given by Kirchhoff and Bunsen for those name, fish-tail, and batwing, does not yield a light of 15

apparatus presents :-Common coal-gas, Ashburton flat of the alkaline earthy metals being the appearances standard sperm candles per foot, though it yields the light observed at the moment the salt is introduced into of 2'4 candles per foot when burnt in a 15-hole argand the flame, it follows that such spectra must be a mixture with a 7-in. chimney. By adding 31'5 grains of naphthalin of the spectrum of the chlorides and of that of the vapour to each foot of this gas, the light-giving value is metal; and secondly, the appearance of lines not raised to between seven and eight candles per foot, accordbelonging to the metal may be considered as a probable, ing to the constitution of the gas with which the vapour if not a certain, indication of the existence of a spectrum is burnt. Oils do not yield quite so high a result as peculiar to the compound with which it is produced. naphthalin ; but they afford from 4'5 to 5 times the light Thus the study of the lines produced by bromides, given by gas alone. To show the economy of gas, I may iodides, and fluorides in the gas Aame may give valuable cite the following results, given to me by Mr. Bowditch": indications, and furnish new proofs of the existence of - A gallon of oil, sold retail for .25., is capable of produca special spectrum for binary compounds. All the ing, with 1000 ft. of London gas, more light than is given metals do not lend themselves with equal facility to by 4000 ft. of gas, or 48.6d, gas and 25. oil against 18s. these experiments. The best defined results are obtained gas alone. The hydrocarbon vessel requires charging with the alkaline earthy metals, and with copper and

about once in fourteen to sixteen days. bismuth.

But let us now return to the production of intense heat

by the combustion of coal gas. This is effected by burn(To be continued.)

ing gas with an excess of air, generally speaking, under

pressure, so as to bring into contact in a given space of PROCEEDINGS OF SOCIETIES.

time a large quantity of gases, especially an excess of oxygen, with a view of rendering perfect combustion of

coal-gas. The first instance, to my knowledge, of the SOCIETY OF ARTS.

perfect combustion of coal-gas as a commercial application was its use in machines for singeing cotton and woollen

fabrics, or for the purpose of removing from their surface “ On some of the most important Chemical Discoveries made all loose and useless fibres. One of the most perfect within the last Two Years."

machines which I have yet examined for accomplishing By Dr. F. CRACE CALVERT, F.R.S., F.C.S. this purpose has been lately introduced to the notice of

manufacturers by Joshua Schofield and Sons, of ManLECTURE 2.

chester. The great merit of their machine consists in the

fact that by it they can vary either the intensity of the Tuesday, April 11, 1865.

flame or its length, according to the pressure at which the On the Discoveries in Chemistry applied to Arts and gases in combustion are made to issue from the machine. Manufactures (Continued):-One of the most curious and in fact, they can adapt with such nicety the action of the important applications which have lately been made of machine to the nature of the fabrics they have to singe chemistry to manufactures is that of coal gas as a means that it can be applied to the finest fabric, such as cambrics, of obtaining intense heats. In fact, heats have been secured and to some of the heaviest materials in cotton, such as which far exceed those previously obtained by the com- fustian. bustion of coals and other carbonaceous matters.

The most remarkable example of the intense heat which To understand how this result has been effected, it is can be obtained by the combustion of gases was brought necessary that I should say a few words on the combus-into notice a few years since by that distinguished chemist, tion of coal-gas. When coal-gas is ignited, the oxygen H. M. St. Claire-Deville (the discoverer of aluminium), of the atmosphere first combines with the hydrogen of the by which he succeeded not only in melting several metals hydro-carbons, either gaseous or sufficiently volatile to which, until his experiments, had resisted all other modes assume a gaseous form, so as to produce water. Whilst a of effecting their fusion, but in melting in his laboratory part of the carbon of these hydro-carbons combines with as much as 25 lbs. of platinum, one of the most refractory the oxygen to produce carbonic acid, the other portions metals known, and running it into one solid ingot. In of carbon float in the mass of ignited gaseous matters, and 1862, the well-known metallurgists, Messrs. Johnson and reach a sufficient temperature to radiate light in all direc- Matthey, invited to their works a large circle of the most tions. It follows, therefore, that the richer the coal-gas scientific men of Europe, who were attending the Exhibition is in hydro-carbons, into the composition .of which enters as jurors, to witness the fusion of 220 lbs. of platinum, and a large proportion of carbon, the more brilliant will be the running of it into one single solid ingot. This wonderful the flame.

exploit in the production of heat was effected in a furnace This is beautifully illustrated by an inrention which I similar in principle to that which had been devised by have the pleasure of showing you through the kindness M. St. Clair-Deville, viz., in a furnace, the inner part of of the Rev. Mr. Bowditch, of Huddersfield, who has lent which was lined with blocks of quick lime, the only me one of the apparatuses which he has lately invented material found by M. Deville to be susceptible of resisting to increase the illuminating power of inferior coal-gas, and the intense heat which was produced by bringing at the which has been applied with success in the city of London upper part of the furnace a large jet of gas and air intiby its learned officer of health, Dr. Letheby.' It consists mately mixed, and working under pressure. The flame, in the introduction of carburetted hydrogens, rich in in passing from the upper part of the furnace and making carbon, into the flame of ordinary coal-gas, thus enhancing its exit at the lower part, produced so great a heat as to in a marked degree its illuminating power. This appa- melt the above-stated quantity of platinum. ratus consists of a gas-tight metallic vessel, which holds The observations of M. Deville socn brought into existthe hydrocarbons, and which has an inlet connected with ence some extremely simple and handy furnaces to effect


Society of Arts.



Nor. 24, 1865.

fusions and assays on a laboratory scale. Some of the round a crucible containing the materials to be assayed, best furnaces contrived for that purpose are due to Mr. and which itself is surrounded by thick earthenware tiles, J. J. Griffin, of Bunhill Row. The principal feature of preventing the heat passing through the furnace from his furnace is using as a generator for heat a large Bunsen radiating itself in all directions, thus concentrating its burner, which consists of a hollow tube, at the bottom of action entirely on the little crucible placed in the centre. which there is an inlet for coal-gas, and at a certain height But the most perfect contrivance of the sort which has yet in the tube a number of openings through which the air been brought to the notice of the public is one due to Mr. rushes in to mingle with the gas; both air and gas issu G. Gore, F.R.S. The following is the description of Mr. at the top of the tube, and when ignited produce an Gore's gas-furnace :-A is a cylinder of fire-clay, about intense heat. The flame so produced is made to play nine inches high and six inches diameter, open at both

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ends, and with a hole at the back part near the bottom, to, and with three projections of fire-clay, P, for supporting lead into the chimney; it is covered by a moveable plate the crucible, Q; it is kept steady by means of three clay of fire.clay, B, with a hole in its centre for the introduc- wedges; R S is an air-valve for closing the bottom of the tion of the crucible or of substances to be melted; this tube L. The gas-burner is a thin metal cylinder, deeply hole is closed by a perforated plug of fire-clay, Ć, for corrugated at its upper end, with the corrugations dimiaccess to the contents of the crucible; and that again is nishing to nothing at its lower end, as shown in the enclosed by another stopper of fire-clay, D. E is a chimney gravings. The action of this furnace is as follows:-Gas of sheet iron, about five or six feet high, kept upright by is admitted to the open tube L by the tap M; it there a ring of iron, F, attached to the top of the furnace. The mixes with air to form a nearly combustible mixture, which fire-clay cylinder is enclosed in a sheet iron casing with a ascends through the burner, and burns in the clay cylinder bottom of iron, to which are fixed three iron legs, G. An O, being supplied with the remainder of air necessary to iron tube, II, with a prolongation, I, supports by means of combustion through the tube H to the outer surface of the the screw, J, the burner, K, and its tube, L, which is open flame by means of the spaces between the corrugations, at both ends. Gas is supplied to the burner by means of The flame and products of combustion pass up through the tap, M, which has a small index, N, attached to it for cylinder O, and then downwards outside of it to the assistance in adjusting the gas. Inside the largest cylinder chimney, the point of greatest heat being at Q. is another fire-clay cylinder or cupola, 0, with open ends, Mr. Gore states that one of his smallest furnaces, con

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