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into other salts of soda. His method of proceeding is as follows:-He treats phosphate of lime, in the state of apatite, coprolites, phosphatic nodules, or bones, crushed or ground, with a sufficient quantity of diluted sulphuric acid to liberate the whole of the phosphoric acid contained therein. The materials are left in contact and digested for about twenty-four hours with occasional stirring. The liquid portion is then drawn off; the residue is washed, and the wash water added to the decanted fluid. The more dilute washing liquors are reserved for the purpose of mixing with fresh sulphuric acid in a repetition of the treatment. The decanted liquid contains free sulphuric and phosphoric acids, phosphate and sulphate of lime, and small proportions of the corresponding compounds of iron, which last may be separated in the form of Prussian blue by the addition of ferrocyanide of potassium. This solution is next evaporated, and when sufficiently concentrated, a quantity of sea-salt is added; the alkaline chloride is decomposed with evolution of muriatic acid, which may be collected as usual. The saline mass left in the retort consists of phosphate and sulphate of soda, which, together with a small quantity of soluble phosphate of lime, is dissolved out with water, at the same time that the phosphate of iron and sulphate of lime are left insoluble. To this solution the patentee adds a quantity of lime, regulating the amount in proportion to that of the phosphoric acid in the liquor, and allows the materials to remain in contact for twenty-four hours, during which period they are frequently stirred. By this reaction all the alkali is liberated, and may be recovered from the solution in the form of caustic soda, or it may be converted into carbonate by passing through the crude liquor, the gaseous products of combination generated in the ordinary furnace. If the latter expedient be adopted, it is recommended to wash the smoky gases before employing them as the source of carbonic acid, and to evaporate the solution in order to obtain crystals of carbonate of soda. The insoluble phosphate of lime is to be collected and dried in the same manner as an ordinary precipitate.

It is doubtful whether much advantage would be gained on the score of economy by following the somewhat intricate details of this succession of processes. The manufacture of alkali by the intervention of phosphoric acid is not so likely to be commercially successful as by the direct operation of sulphuric acid.

treating fatty and oily matters for obtaining their acidification, and in the apparatus employed therein."-Petition recorded 31st January, 1862.

288. William Clark, Chancery Lane, London, "Improvements in processes for preserving and colouring wood, denominated xylochromic and xyloplastic processes."A communication from Messrs. Heinrich Sperl, Richard Hogen, and Wolfgang Springer, Nuremberg, Bavaria.Petition recorded 3rd February, 1862.

294. Richard Archibald Brooman, Fleet Street, London, "Improvements in the manufacture of hard and soft soaps, and in the preparation of liquids for washing linen and other textile fabrics."—A communication from Léo Bachellerie, Paris.

328. William Clark, Chancery Lane, London, "Improvements in preserving timber, which are particularly applicable to the timbers of ships or other maritime structures." A communication from M. Henri de Lapparent, Boulevart St. Martin, Paris.

338. Marc Antoine François Mennons, Rue de l'Echiquier, Paris, "Improvements in the treatment of coprolites and other fossil phosphates of lime."-A communication from Guillaume Louis Edourd Buran and Louis Goupy, Rue du Grand St. Michel, Paris.

340. James Dickson, Tollington Road, Holloway, London, "Improvements in voltaic apparatus and in the production of voltaic electricity."

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Notices to Proceed.

2580. William Smith, Salisbury Street, Adelphi, London, increasing the illuminating power of gas."—A communi'Improvements in the apparatus for and method of cation from Hugo Carstanjen, Cologne, Germany.

ments in smelting copper, gold, and other ores."—A 2605. Hugh Macmekan, Stratford, Essex, "Improvecommunication from Rowland Vounder Rodder, Alberton, near Adelaide, South Australia.

2609. Robert Mushet, Coleford, Gloucestershire, "A of titanium and iron.” new or improved manufacture of titanic pig metal or alloy

shire," An improvement or improvements in collecting 2623. Josiah Timmis Smith, Barrow, Furness, Lancathe inflammable gases evolved from blast furnaces."

2637. Robert Mushet, Coleford, Gloucestershire, "An improvement or improvements in the manufacture of a certain metallic alloy.'

Chancery Lane, London, "Improvements in processes or 2643. George Henry Birkbeck, Southampton Buildings, means employed for separating or extracting silver from lead."-A communication from Jules Frederic de la Batie, Paris.

galvanic and magneto-electric currents, and in machinery employed in making some of the apparatuses."

2784. George Tomlinson Bousfield, Loughborough Park, Brixton, Surrey, "Improvements in electroplating or depositing metals."-A communication from Jabez Ellis Walcott, Boston, Massachusetts, U.S.-Petition recorded 5th November, 1861.

1214. Decomposition of the Compounds of Aluminium, and Coating Metals with Aluminium or its Alloys. T. BELL, Gateshead. A Communication. Dated May 13, 1861. THIS invention consists in effecting the reduction of aluminium compounds, particularly the double chloride of aluminium and sodium, by the agency of voltaic electricity; 2656. Isaac Louis Pulvermacher, Oxford Street, London, and in employing the same means for the purpose of coat-"Improvements in apparatuses for the production of ing metals with aluminium. By this process the patentee converts the surface of copper into aluminium bronze. The mineral cryolite, which readily furnishes aluminium under the reducing action of sodium, would probably constitute one of the most available sources for the preparation of this metal by the help of the galvanic battery. 1223. Manufacture of Steel. W. CLARK, Chancery Lane, London. A Communication. Dated May 14, 1861. THE patentee claims the mode of converting iron into steel by treating it at a high temperature with a mixture of coaldust and alkaline carbonate, or with other matters containing hydrogen and nitrogen employed conjointly with an alkali. Such combinations are stated to be very efficacious in the removal of sulphur from the iron, so that the metal undergoes a process of purification at the same time that it is converted into steel.

2822. William Edward Newton, Chancery Lane, London, "Improved apparatus for manufacturing and containing gaseous liquids."-A communication from Pierre Prudence Henri Couillard, Rue St. Sebastien, Paris.-Petition recorded 9th November, 1861.

2924. George Henry Polyblank, Gracechurch Street, London, "A new or improved method of protecting and preserving photographic and other prints, water-colour drawings, and other works of art from injury and decay."

-Petition recorded 21st November, 1861.

3150. Emile Cajot, St. Servais, Belgium, "Improvements Grants of Provisional Protection for Six Months. in the treatment of pyrites for the manufacture of iron." 262. Pierre Scheurweghs and Alexandre Joseph Aurele-Petition recorded 14th December, 1861. Henry de Boisserolle, Paris, "Certain improvements in

23. Hermann Eschwege, Mincing Lane, London, "Im

154

Miscellaneous-Answers to Correspondents.

provements in treating wood and other vegetable spirit." -Petition recorded 2nd January, 1862.

81. Thomas Ramsay, Newcastle-on-Tyne, "Improvements in the manufacture of coke."-Petition recorded 11th January, 1862.

MISCELLANEOUS.

Chemical Society. The next Meeting of this Society will take place on Thursday next, when a Paper will be read by Mr. A. H. Church, "On the Isolation of Phenyl."

Royal Institution.-The following Lectures will be delivered in the ensuing week :-Tuesday, March 18, at three o'clock, John Marshall, Esq., " On the Physiology of the Senses." Thursday, March 20, at three o'clock, Professor Tyndall, "On Heat." Friday, March 21, at eight o'clock, F. A. Abel, Esq., "On some of the Causes, Effects, and Military Applications of Explosions." Saturday, March 22, three o'clock, H. F. Chorley, Esq., "On National Music."

Plumbago in India.—The Bombay Gazette of the 12th ultimo announces the discovery of considerable quantities of black lead at Sonah. Dr. Thompson, Civil Assistant-Surgeon, Goorgaon, reports that the quality of the samples he has examined is such that they bear a favourable comparison with average specimens from the North of England. By chemical analysis the Indian blacklead was found to consist in 100 parts, of

Carbon

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78.45

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The proportion of earthy constituents, 17.2 per cent., is somewhat higher than would be found in first class blacklead; but this amount does not appear excessive in comparison with that contained in the ordinarily good qualities of this mineral.

Bessemer Steel.-The rapidity with which the Bessemer process is being at last adopted is extraordinary. Whatever may be said of the earlier failures in the attempt to produce good malleable iron or steel by blowing a blast of air through a quantity of melted cast iron, it is now certain that ingots of the best quality may thus be produced in from a quarter to half an hour, and, if the iron is taken as it comes from the blast furnace, without any expenditure of fuel whatever. Mr. Bessemer's memorable experiments, made six years ago in Baxter House, were with a good quality of Welsh iron-Blaenavon we believe-which happened to have but little sulphur or phosphorus, and a good quality of metal was certainly made, as many who secured samples at the time can testify. But when the pneumatic process came to be applied to other irons it proved, in several cases, unsuccessful. No particular attention was directed to the impurities of the iron, since there was no prima facie reason for supposing that their presence, so long as it did not prevent the production of merchant able iron by the ordinary process, would cause special difficulties in the new. But difficulties there were, and at one time it was believed by most of those who had paid much attention to the new process, that it had failed completely, which was, of course tantamount to believing either that the first successes were achieved by juggling, or that what had once been done could not be repeated. Mr. Bessemer persevered, however, and was able to give a good account of himself and his process, three years ago, at a meeting of the Institution of Civil Engineers. From his

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explanation it then appeared, for the first time, that only the presence of sulphur or phosphorus, in notable quantities, in the iron, affected the conversion of pig metal into food malleable ingots, in less than half an hour, and without either fuel or manipulation. Great difficulty, it was true, had been experienced in finding a lining material, capable of withstanding the heat of the converting vessels, but it was at last found that the "ganister," which occurs in abundance in the neighbourhood of Sheffield, was perfectly adapted for the purpose, and already have nearly one hundred charges, averaging nearly a ton each, been converted in one vessel at Mr. Bessemer's works, with one lining only. Hematite iron having been adopted, and the refractory properties of ganister sufficiently tested, almost the only difficulties in the way of the new manufacture had been overcome before the meeting, last summer, of the Mechanical Engineers at Sheffield. It was then that Mr. Bessemer was first enabled to bring the action and results of the pneumatic process visibly before a great body of practical men, all of whom had every opportunity afforded them for examining into all its details, which, however, are very few and exceedingly simple. A ton of iron worth under 3. was converted, with a loss of less than 17 per cent., into a material intrinsically worth, in comparison with other steel, 40l. or 50l. The fuel was only that (say 3 cwt.) employed for melting in the cupola, and the actual cost for labour could not have amounted to as much as one shilling. The product could be graduated to any required hardness or toughness, the blast being first kept of the iron, immediately after which, the blast being on until nearly all the silicon and carbon were burnt out stopped, a measured quantity of melted cast iron, containing an ascertained proportion of carbon, was added. If enough carbon was restored in this way the ingot would be one of highly carbonized, hard, and unweldable steel, having great cohesive strength. If very little carbon were restored, at the conclusion of the process, the ingot would be soft, nearly as ductile as copper, and capable of being readily welded, while its strength would be from one-third to one-half greater than that of the best Yorkshire malleable iron. The converting process being completely under control, hundreds of tons of metal could be produced of any desired working quality.—Engineer.

and

Compound of Iron Ammonium. Dr. Meidinger (Neues Jahrb. für prakt. Pharm., Bd. xvi. 8. 295) says, that a voltaic current passed through a mixed solution of a protosalt of iron and sal ammoniac produces a bright metallic precipitate which resembles polished steel in appearance. It forms a very thin casing on the pole which scales off as the deposit increases. Carefully rinsed with a good deal of water and dried on blottingpaper, it evolves, when treated with a caustic alkali, a strong smell of ammonia. When heated, the smell is also perceived, but is quickly dissipated. The precipitate when put into water and heated nearly to the boiling point, evolves a good deal of hydrogen. The author has no doubt that the precipitate is an alloy of iron and ammonium; others, perhaps, will think differen ly. The most ammonia he found in a precipitate was 1.5 per cent.

ANSWERS TO CORRESPONDENTS.

Preparation of Cerium Salts from Cerite.-W. C.-We have found the following plan effectual:-Powder the mineral and dissolve it in aqua regia, evaporate nearly to dryness, and e tract with water; add ammonia till a precipitate just begins to take place, carefully avoiding excess (if excess be added, exactly neutralize it with acetic acid). Add tartrate of soda to complete precipitation, avoiding excess. Collect the precipitate of tartrate of the cerium metals and tartrate of lime, wash well, and extract with ammonia. Tartrate of lime remains undissolved. Filter and re-precipitate the cerium tartrates with hydrochloric acid. Wash, dry, and ignite.

C. R. The specimen is too small for accurate analysis, but we can

find no silver in it.

Acetate of Tin.-A correspondent wishes to know the best plan for making this compound in the liquid state and neutral, about 14 T.

THE CHEMICAL NEWS.

VOL. V. No. 122.-April 5, 1862.

THE EVIDENCE OF "EXPERTS."

THE evidence of "Experts" is just now the object of general derision. Smart newspaper writers, wishing to indite a telling sarcastic article, select the discrepancies in scientific evidence for a theme; noble Lords, anxious to enliven the dull debates of our hereditary legislators, find nothing so provocative of laughter as a story about the differences of "mad doctors; " and barristers, ready to advocate any opinion, and anxious, perhaps, for a monopoly of the "any-sidedness," when addressing a jury, dilate with well-simulated indignation on the fact that eminent scientific men are to be found in the witness-box on opposite sides. But there is nothing in these differences to excite astonishment. Scientific men are constantly called upon to express opinions on matters which do not admit of demonstration, and about which men may conscientiously come to different conclusions. Whether a fever that raged in a certain neighbourhood was or was not caused by a stench evolved from some manufactory in the vicinity, must be a matter of opinion; for at present it is incapable of proof or denial either way. Whether a given substance is or is not coal, must remain a matter of opinion until philosophers have arrived at the true definition of a coal. Whether the act of subscribing to the Society for the Conversion of the Jews is a proof of insanity in the subscriber; or whether the doctor who urges the fact as a proof of insanity is not mad, are things open, perhaps, to less doubt, but still may be matters of opinion. On all such points, men do, will, and may reasonably differ. But scientific witnesses and our readers will see that we here use the term "scientific" in the loosest way-are sometimes called upon, and sometimes go out of their way, to speak to things the truth or falsehood of which can be easily demonstrated. That one drop of benzol, four ounces of pure water, and fifteen drops of nitric acid, will produce a Magenta-coloured liquid, is either a fact or exactly the opposite; and any one who will take the trouble to make the experiment may settle which for himself. And whether the presence or absence of phosphates is likely to be proved by sulphate of copper and chloride of lime, is well known to every one who knows anything of chemical analysis. But how can a judge and jury, all profoundly ignorant of chemistry, estimate the value of such assertions? If any barrister had tried to persuade Mr. Baron Channell and a jury that an individual with red hair could not recover on a policy for fire insurance, both judge and jury would have laughed at the absurdity of the notion; and yet the barrister would have advanced nothing more absurd or untrue than some statements which were listened to gravely at Stafford. The fact is, the machinery of ordinary judge and jury for the trial of cases which depend on chemical evidence is simply "a mockery, a delusion, and a snare." A chemist might just as reasonably sit at Westminster to decide points of law. How can people ignorant of chemical science judge between the contradictions of

chemists, or estimate at their proper value the evidence of a druggist who "makes his own tinctures," and does not remember the composition of cyanogen, for the compounds of hydrogen are so complicated, and the evidence of a Faraday or a Miller? It is only a few days since the leading daily Journal remarked that, "one of the most unsatisfactory parts of our law of evidence is that which relates to the admission of the testimony of experts." The law is indeed in an unsatisfactory state, and it cannot too soon be amended. The interests of science, truth, and justice demand that the attempt be made at once; and the attention of the Legislature and Government should be called to these Stafford trials as excellent illustrations of the necessity for a change. If a chemist of acknowledged reputation were in such cases to sit with the judge as assessor, it would probably have the effect of keeping out of the witness-box men who are wholly incompetent to form a correct opinion, although it might not in all cases ensure unanimity in the witnesses.

SCIENTIFIC AND ANALYTICAL CHEMISTRY.

On the Equivalent of Lithium, by M. L. TROOST. THE discovery of two new metals in lithium ores, and the valuable aid afforded by the spectrum, enable us to investigate, with some chance of success, the cause of the differences observed in determining the equivalent of lithium. With this view, I have re-examined the salts of lithium prepared and described by me in the Annales de Chimie et de Physique, Third Scries, vol. li. By submitting them to spectrum analysis, with the co operation of M. Grandeau, I find that the composition of these salts vary greatly according to the nature of the substances from which they were prepared. The salts, which I obtained by double decomposition, extracted directly from sulphates, contain, besides traces of potash and soda, cæsium and rubidium in considerable and nearly equal quantities. The salts obtained by the chloride, purified by alcohol and ether, also contain these two metals, with traces of sodium. The carbonate of lithia, and the salts derived from it, contain no trace of foreign metals.

I have obtained this body, as I have stated, by treating the chloride with carbonate of ammonia; the precipitate, washed and dried, was held in suspension in water, and a current of carbonic acid passed through it; it dissolved rapidly, and precipitated itself again, in a crystalline state, when boiled. Again dissolved and precipitated, a salt was obtained which, under spectrum analysis, showed no indication of soda nor of the two other metals. The absence of these bodies is easily accounted for by the solubility of their carbonate. Carbonate of lithia, then, must be employed for preparing the compounds to be used in determining the equivalent. In the paper

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above cited, as I attributed to this salt a greater degree of purity than to all the others, I have made use of it in my researches, and with it I prepared the chloride which I forwarded to M. Dumas for the determination of the equivalent.

The purity of the chloride used being established, it becomes more than probable that the number found by M. Dumas is the exact equivalent. I have endeavoured to verify this by the use of two methods entirely different.

ness.

Chloride of lithium, heated while exposed to the air, decomposes partially, which at first made me avoid using it. I have since, however, proved in the following manner that a very exact result can be arrived at by the use of this body:-Place the chloride in a platinum vessel in the middle of a Bohemian glass tube traversed by a current of dry hydrochloric acid gas. Heat to dryWhen cold, replace the hydrochloric acid gas by a current of dry air. Close the tube containing the vessel with good india-rubber stoppers, and weigh it. A similar glass tube, also stopped with india-rubber, may be used as a counterpoise. The weight being determined, replace the tube under experiment, and heat the platinum vessel for two hours in a current of dry hydrochloric acid gas; finish the operation, and conduct the weighing under the same conditions as before. It will be found that there has been no loss of weight. It is then evident that the chloride does not decompose when placed under the conditions described.

In precipitating by nitrate of silver certain quantities of chloride which, according to M. Dumas, may be used in the ratio of one to two, I obtained,

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1. 7:030) mean, 7.01.

II. 6'99 To test this result by another method, I again took the carbonate of lithia and estimated the lithia in separate portions, by combining it with sulphuric acid and the carbonic acid, by heating the carbonate with an excess of pure powdered quartz. The number, rather too low, though equal to that of Berzelius, which I had previously obtained, might be due to the ready decomposition of carbonate of lithia, under the influence of even moderate heat. To avoid this cause of error, I took care not to heat it above 100o, and in one experiment I even dried the carbonate at the ordinary temperature, in vacuo, in presence of sulphuric acid. I have likewise proved, in the following manner, by employing silica, thatI. 970 mgrs. carbonate contain 577 mgrs. carbonic acid, II. 1782 "

99 1059

which gives as the equivalent,

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The estimation of lithia by sulphuric acid gave, for 1217 milligrammes of carbonate, 1808 milligrammes of sulphate; making the number 7'06. The equivalent of lithium is then 7, as M. Dumas concluded from his experiments; and the discovery of the two new metals in the lithium ores do not invalidate his conclusions.

Another confirmation of this equivalent-obtained also by M. Mallet-is derived from the experiments of M. Karl Diehl, tested with the spectrum analysis in Bunsen's laboratory, and described in the Annales de Wöhler et Liebig, January, 1862. In fact, M. Karl Diehl, by determining the carbonic acid expelled from the carbonate

CHEMICAL NEWS, April 5, 1862.

by diluted sulphuric acid, by four concurring experiments, arrives at the number 7'026.

I have, in the course of my experiments, repeatedly verified the fact, already stated, that anhydrous or hydrated lithia, as well as pure salts of lithia, do not act in platinum. The alteration of this metal, when it ascends, is attributable to compounds of cæsium and rubidium. MM. Bunsen and Kirchhoff have, in fact, proved that this property is possessed by a sub oxide of these metals.-Comptes-Rendus.

Oil of Cajuput as a Means of Distinguishing Between Amber and Copal, by HARRY NAPIER DRAPER, F. C.S. SEVERAL oxygenated volatile oils, notably those of lavender, rosemary, and peppermint, possess the property of softening copal resin in the cold, and of dissolving it at higher temperatures, to a greater or less extent. Oil of cajuput, however, readily dissolves copal at the ordinary temperature, forming a perfectly transparent solution, from which the oil evaporates, leaving a very brilliant coating of the resin. Amber is totally insolubie in oil of cajuput, even at the boiling point of the latter; and, as some of the specimens of copal often simulate and are mistaken for amber, this different behaviour may serve as a ready means of distinguishing between the two resins. I may add, as a fact also possessing some technical interest, that the solution of copal in cajuput oil is easily miscible with alcohol.

Dublin, March 28.

On the Synthesis of Acetylene by the Direct Combina tion of Carbon with Hydrogen, by M. BERTHELOT. THE hydrocarbons and alcohols are the starting points in the formation of other organic compounds; therefore, after having succeeded in effecting the synthesis of the alcohols and their ethers from hydrocarbons, I directed all my efforts towards the formation of the hydrocarbons themselves from their elements. I have already given different methods by which this end may be attained, and the most simple carburets obtained, starting from carbon and hydrogen. But if these methods leave no doubt as to the final result, they are nevertheless indirect, and only yield circuitous ways of realising the initial combination of carbon with hydrogen. In the present state of our knowledge, there was scarcely any hope of proceeding otherwise. We all know, in fact, what is the chemical indifference of carbon at the ordinary temperature even to the most powerful reagents. This indifference only ceases at a red heat, and then only for oxygen and sulphur. But as to hydrogen, all its combinations with carbon hitherto obtained from organic products are actually destroyed under the influence of a red heat; it would therefore seem chimerical to attempt their direct formation.

My last researches on acetylene appeared, however, to authorise new attempts. This compound is the least rich in hydrogen of all the carburetted gases, for it is the only one which contains its own volume without

condensation :

CH2 4 volumes: H2 = 4 volumes. Acetylene is at the same time the most stable of hydrocarbons. Not only is it formed in large quantity at the expense of olefiant or marsh gas under the influence of heat or the induction spark, but it may be produced by the action of the latter, although in small proportion,

at the expense of even benzol and naphthalin-that is to say, at the expense of carburets which we have hitherto been accustomed to regard as the most stable of all. In the presence of these facts, I thought that there was still room for the attempt to form acetylene by the direct union of its elements.

Under these new conditions, the experiment succeeded fully. The combination of hydrogen with carbon took place instantly, as soon as the arc shone. Acetylene was produced, and that is the only product which I recognised in the reaction; its production continues as long as the electric arc passes; it may be produced indefiBut before undertaking my experiments, it was neces-nitely with the same carbons, as long as the transport of sary to ensure the purity of the materials with which I matter which takes place between the poles has not had to work. entirely disentegrated them.

Hydrogen is easy to prepare by means of zinc in a state of purity and dryness, but with carbon it is otherwise. Carbon is usually obtained from organic substances; there are, therefore, different kinds of carbon, containing variable quantities of hydrogen. A sustained calcination removes the greater part; but the best calcined carbon-retort carbon, for instance-in spite of its semi-metallic properties, still retains some trace. This last carbon contains, besides, a small quantity of tarry matter, the unsuspected presence of which might give rise to serious errors. To completely and certainly eliminate the hydrogen and tarry matter contained in the carbon, I know of only one process-the employment of chlorine at a red heat. Chlorine, moreover, presents this advantage in purifying carbon, that it separates sulphur, iron, aluminium, silicium, and most of the metals in the form of volatile chlorides. It has thus been employed by M. Dumas in his researches on the equivalent of carbon. If I insist upon these pre. cautions, it is because their omission would remove all the demonstrative character from the results which I am about to give, by leaving it uncertain whether the formation of acetylene should be attributed to the direct union of carbon with hydrogen, or to the decomposition of some hydrogenised matter contained in the carbon.

I therefore employed retort carbon heated to redness, for some time in contact with air, and then heated to redness for an hour and a half in a current of chlorine.

At first I had recourse to the action of heat alone: I heated the purified carbon to a bright red heat in a current of hydrogen, but without success. Wishing to increase the temperature still higher, I had recourse to the kindness of M. H. St. Claire Deville, who placed at my disposal his apparatus at the Ecole Normale, and his great experience with heat. But I had no more success than I had had before; after having kept the temperature at a white heat for more than an hour, we saw the porcelain tube containing the carbon fuse as if it were glass, without obtaining the least trace of acetylene.

To carry the experiment further, electricity remained with its powerful effects, or the proper influence of this agent, together with that of heat. I employed, first, the induction spark in contact with calcined carbon, or in contact with finely divided carbon, produced in the apparatus itself by the decomposition of marsh gas; but the experiment still failed, which I attribute to the carbon not being heated by the induction spark.

Finally, I had recourse to the battery, and the electric arc produced between two carbon poles, with the excessive elevation of temperature and the transport of carbon from one pole to another. I took care to purify the carbon poles from all tarry and hydrogenous matter, by the employment of chlorine, as explained above."

* Desiring to control my results from this point of view, I took a fragment of carbon, purified for my experiments, weighing 1078 grammes, and without pulverising, or even breaking it, I burned it in a current of oxygen. I obtained o'oro gramme of water; that is to say, 1 milligramme of hydrogen. This probably owed its origin to hygrometric water.

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the Academy. The acetylene formed round the poles is I had the honour to perform this experiment before carried away by the current of gas, and condensed in a solution of ammoniacal protochloride of copper, producing a red precipitate of cupreous acetylide. The experiment is equally striking, on account of the employment of the electric light and the characteristic formation of the precipitate. It is so easy of performance, that it may be readily reproduced as a lecture experiment. Nothing is easier than to obtain in this way notable In the conditions under which I operated there were formed about ten quantities of acetylide of copper. cubic centimètres of acetylene per minute; the proportion of carbon entering into combination with the hydrogen may be estimated at about half that which is disengaged and carried from one pole to the other. with hydrochloric acid, pure acetylene is reproduced. Upon subsequently treating the acetylide of copper After having satisfied myself that the carbide obtained by this means possessed all the characteristic properties of acetylene, I made an analysis of it :

20 volumes of the carbide obtained from its elements, being burned in the endiometer, yielded 40 volumes of carbonic acid, absorbing 51 volumes of hydrogen.

20 volumes of acetylene ought to produce
40 volumes of carbonic acid, absorbing
50 volumes of oxygen.

elements, is not an isolated fact, but a point of departure.
Acetylene thus formed by the direct synthesis from its
I have, indeed, shown how it may easily be changed into
olefiant gas by the simple addition of hydrogen:
C1H2+
= CH1

H2

Acetylene. Hydrogen. Olefiant gas. From olefiant gas may be formed alcohol; and we thus enter into the chain of bodies whose ensemble constitutes organic chemistry. To all these syntheses and progressive formations, that of acetylene will henceforth allow the starting-point to be a direct synthesis.-ComptesRendus, liv. 640.

On the Estimation of Selenium, by M. H. ROSE. SULPHUROUS acid is the best reagent to precipitate selenium when this element is in solution in the state of selenious acid; it is necessary that the precipitation be performed in the presence of hydrochloric acid. The sulphurous acid may also be replaced by phosphorous acid; likewise in the presence of hydrochloric acid; but the reduction takes place much slower than when sulphurous acid is used.

Mr. Oppenheim has shown that selenium may be estimated by fusing the body containing it with cyanide of potassium, dissolving the fused mass in water, and then super-saturating the solution with hydrochloric acid

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