ABSORPTION OF SALTS OF POTASSIUM BY HYDRATED FERRIC OXIDE AND HYDRATED ALUMINA. ABSORPTION OF SALTS OF AMMONIUM BY HYDRATED FERRIC OXIDE AND HYDRATED ALUMINA. Two points strike us at once on inspecting these tables. In the first place, the absorbent action of alumina is clearly much less than that of ferric oxide. With carbonate and sulphate of potassium the oxide of iron takes up about four times as much as the alumina; with the corresponding ammonium salts it takes up about three times as much as the alumina. In the next place, it is very evident that both with oxide of iron and alumina the amount of absorption varies greatly with different salts of the same base. The carbonates of potassium and ammonium are seen to have been absorbed to a considerable extent, the sulphates to a small extent, while of the chlorides and nitrates only traces were taken up. This order of absorption, it will be remarked, is the same as that generally observed in absorption by soil. With soil, however, the absorption from the sulphate, chloride, and nitrate, is proportionately far greater than in the present case. The difference is, doubtless, owing to the important assistance given by the lime of soil, which, combining with the acids of these salts, allows the bases to be absorbed as hydrates. It was attempted in a few experiments to imitate the conditions of soil by adding carbonate of calcium to the hydrated oxides. Some further absorption was obtained in a few cases by this means, but the imitation of the conditions of soil was clearly very imperfect. It was a point of great importance to decide if the absorption in these experiments was due to a chemical or a physical action. With this view attention was paid to any evidence of a decomposition of the salt during the reaction. In the case of carbonate of potassium, it was found that the carbonic acid was not absorbed to the same extent as the potassium, but that an excess of acid remained in For the analytical details the reader is referred to the Journal of the Chemical Society, vol. vi., p. I. These formulæ represent the composition of the hydrates actually employed. The reader will observe, by reference to the table, that the strength of the salt solutions employed was not in every case regu lated by the chemical equivalent of the salt. In this, and several other particulars, the experiments admit of considerable improvement. These errors, pointed out by experience subsequently gained, do not, however, affect any of the conclusions here drawn. Thus, the weaker the solution became during the absorption, the greater was the proportion of carbonic acid taken up. It seems that ferric oxide commences by absorbing potash almost to the exclusion of carbonic acid; by so doing, the proportion of carbonic acid in the liquid must be increased. But this accumulation of acid in the liquid appears to act as a check on the further decomposition of the potassium salt, which, therefore, takes place to a less and less extent as the absorption progresses. In one experiment with hydrated alumina, the decomposition of the carbonate of potassium was complete, potash was taken up, but no carbonic acid. In the experiments with carbonate of ammonium, the absorption of carbonic acid was determined in one instance only. The ferric oxide in this case absorbed carbonic acid and ammonia in the proportions to form neutral carbonate; the salt used had contained, as is usual with the commercial article, an excess of carbonic acid-a slight decomposition had therefore probably taken place. In the experiments with sulphates, it was noticed that the solution of sulphate of ammonium became distinctly alkaline on contact with either ferric oxide or alumina; mination of the amount of sulphuric acid and ammonia with the latter the reaction was very marked. A deterremoved by the alumina showed that, for 10 equivalents of ammonia, 28-2 equivalents of sulphuric acid had been By an equivalent of sulphuric acid, is here understood the amount required to form sulphate of ammonium with 1 equivalent of ammonia. NEWS taken up. The acid had here been absorbed in far greater We have here very distinct evidence that the absorption by ferric oxide and alumina was attended with a chemical decomposition of the salt absorbed; this decomposition was, however, rarely complete, both acid and base being in most cases taken up, though in unequal proportions. To a chemist, alumina and ferric oxide are known to behave as feeble bases towards strong acids, and as feeble acids towards strong bases; we can, therefore, from a chemical point of view, readily understand the preponderating absorption of base from the salt of a weak acid, as a carbonate, and the preponderating absorption of the stronger acids from their comparatively feeble combinations with ammonium. Again, the well-known readiness with which ferric oxide and alumina form highly basic compounds, and also salts (as alum) containing two bases to one acid, seems to render a purely chemical explanation of the whole of these reactions quite easy. It is not, however, denied that hydrated ferric oxide and alumina are capable of taking up certain substances by virtue of physical attraction, but it is believed that such an action has had no place in the absorption of the salts here described. A single experiment was made as to the retention of potash by ferric oxide when the latter was washed with water. Hydrated ferric oxide which had absorbed potash from the carbonate was submitted to two washings with thorough agitation, each washing remaining in contact one day. The ferric oxide was then found to have lost two-thirds of its potassium. The washing was sufficient to have reduced a perfectly soluble salt toith its original quantity. The compound with iron was thus decomposed by water, but with some difficulty. (To be continued.) PROCEEDINGS OF SOCIETIES. CHEMICAL SOCIETY. Fe 03 These results correspond pretty well with the formula of kaolinite, Al2O32SiO2+2aq, if we suppose several replacements, such as a partial replacement of hydrogen by sodium or potassium, and of aluminium by iron. The other of the above-mentioned minerals is chalcophyllite. The recorded analyses of this mineral are by no means satisfactory. Chevenix found in it 58 per cent of cupric oxide, and 21 of water; Hermann, 44:45 per cent of CuO, and 31'19 of water; and Damour, 52.61 of CuO, and 23 a6 of water. Of course, it was rather difficult to assign a formula for so variable a substance. Mr. Church has devoted much time and labour to an endeavour to clear up the mystery of its constitution; and he obtained the following percentage as the mean of several analyses:— These results lead to the formula- 14:06 46.14 5'97 0'60 15'54 3175 or as well to 8CuO,Al2O3, As2O3+25aq.; and these elements of chalcophyllite may be viewed as arranged in the following manner : It ought to be stated that chalcophyllite cannot be dried, even in vacuo, without an entire change in its appearance; the transparent beautiful green crystals become opaque and of a more bluish green. These changes correspond to a loss of 13.79 per cent of water. At 100°, the insignificant further loss of o'31 per cent of water takes place. Messrs. BOLAS and GLOVES communicated a paper on Professor WILLIAMSON, F.R.S., President, in the Chair. "Tetrabromide of Carbon." THE following gentlemen were elected Fellows:-G. Mr. BROWN read a paper "On Vapour Densities," wherein he gave a historical review of the various methods employed for the determination of vapour densities. Mr. CHURCH Communicated "The Analyses of Two Cornish Minerals." The one, restormelite, was obtained from the Restormel Iron Mines, and may be regarded as a variety of kaolinite, standing nearest to the lithomarge group. Its specific gravity and its hardness are nearly the same as those of lithomarge. In its percentage of silica and alumina (its chief constituents) it does not differ from that of lithomarge; but, while restormelite contains 7 per cent of soda and potash, lithomarge contains a mere trace of these alkalies. Mr. Church considers restormelite as preserving in its alhalies more evident traces of its feldspathic origin than we usually find in such alteration-produ&s. The following percentages were obtained in six analyses : This combination is obtained (1) by heating bisulphide of carbon with bromide of iodine, in a sealed tube, to a temperature of 150° C. for about 48 hours; (2) by heating bromopicrin with bromide of iodine in a flask furnished with a digestion-tube till the reaction is completed, which is indicated by the disappearance of the bromopicrin; (3) by heating bromoform with bromide of iodine, in a sealed tube, to about 150° C. for 24 hours. In all the above processes, terbromide of antimony may be substituted for the bromide of iodine. The tetrabromide of carbon is obtained in a pure state by distillation. It is a white substance, crystallising in lustrous plates, melting at 91° C., of an ethereal odour, somewhat resembling that of carbon tetrachloride, and of sweetish taste. It does not dissolve in water, but readily in ether, hot alcohol (from which it is deposited, on cooling, in the crystalline state), carbon bisulphide, chloroform, bromoform, benzol, and American oil. Sodium amalgam reduces it to bromoform, and then into methylene dibromide. The authors propose to carry on their investigations of this interesting compound. 224 Manufacture of Sulphuric Acid. CORRESPONDENCE. MANUFACTURE OF SULPHURIC ACID. To the Editor of the Chemical News. SIR, I cannot see how your correspondent "O. V." can have deduced from my letter the statement that "Mason's ores require much less nitre per 100 parts of sulphur burnt than do other ores. My statement was that 100 parts of sulphur (meaning pure brimstone) required, in the hands of different manufacturers, varying proportions of nitrate of soda; and I ventured the opinion that the variation was due to a want of uniformity in the conditions of the manufacturing process. The subsequent mention of Mason's ores is accounted for by the absence of precise information as to whether Mr. Spence used brimstone or sulphur ores in his process. I have had experience of Mason's ores, and find them very manageable; but, of course, the quantity of nitrate used with different ores of sulphur will vary in direct proportion to the quantity of sulphur they contain.I am, &c., DAVID BASIL HEWITT, B.A., T.C.D. "St. Helen's, April 29th, 1870. "Dear Sir, Will you pardon the liberty I take in addressing you? but I have been very much interested in your account of your trial of Dr. P. W. Hofmann's suggestions as regards the economical production of sulphuric acid. As I read Dr. Hofmann's original paper, and his subsequent letter seems to confirm this view, the important point in his improvement is that the mixed sulphurous and nitrous acid gases should not be permitted to come in contact with vitriol of lower strength than 143° Twad. until a reaction has taken place between them, and that, if it should come in contact with acid of a lower density, a large proportion of the nitrous acid is decomposed, with production of free nitrogen. If this be a correct conclusion, it appears to me that your re-arranged plan of working (as described in the CHEMICAL NEWS for April 22nd) introduces the very evil Dr. Hofmann tells us we should avoid. The difficulty under which I labour in my study of the matter is that, notwithstanding this, you have actually succeeded in reducing considerably your consumption of nitrate, and that you, with your great practical experience, consider the saving to be due to your having adopted Dr. Hofmann's suggestion. Though I have myself paid much attention to this manufacture, I yet feel considerable diffidence in writing to you that the diminution in your requirements of nitrate of soda is owing to quite another cause, or perhaps more than one. But I suggest to you whether, in your plan of working, as described in the before-mentioned paper, you are not condensing a considerable proportion of your make of vitriol in the first two chambers, and that your two next CHEMICAL NEWS, May 13, 1870. chambers, while, of course, allowing the formation of more vitriol, play more distinctly the part of a GayLussac's column or tower, the strong vitriol absorbing the nitrous gas, which, the vitriol being returned to the first chamber, is again evolved, and again becomes available for the same work as it had before performed. I have a strong opinion that the whole saving you have effected, and, I may add, the whole saving you expect to accomplish when your re-arrangements are complete, may be accounted for in this way alone, and without any consideration of Dr. Hofmann's suggestion. I should feel greatly obliged if you would favour me with your opinion upon the points I have called in question. To anyone engaged in the manufacture, economy in the use of nitrate is of the utmost importance; and I plead my anxiety on the subject as my excuse for troubling you with so long a letter. I am, yours faithfully, J. W. KYNASTON. "Peter Spence, Esq." "Dear Sir, I have much pleasure in answering your letter of 29th, to hand this morning. I am always ready to pick up any promise of improvement in the manufacture of sulphuric acid, and most ready to communicate all I know upon the subject. I therefore took up at once Mr. Hofmann's suggestion, and, although I did not, and do not now, believe in his theory, it at once suggested to me what you exactly describe as, in fact, the Gay-Lussac tower in principle, but without the apparatus. The theory of sulphuric acid production, as well as the facts of the GayLussac process, in my opinion, disprove Mr. Hofmann's hypothesis. The theory is that the SO2 and NO, unite to form sulphate of nitric oxide, which, by water or steam, is resolved into SOHO and binoxide of nitrogen, which, in contact with air, instantly forms NO, ready for a repetition of the process. Now, not one-tenth of NO, is sent into the chambers equivalent to combine with all the SO, going in at the same time: the combination must, then, be made at least ten times (I should probably be more correct by saying twenty times, but ten is sufficient). If, then, 10 per cent of the nitric oxide is destroyed each combination, it would all be destroyed when the process is completed. Yet I have seen the Gay-Lussac process at work when, after, I think, ten chambers had been traversed, it took up so much of the binoxide of nitrogen that only one-fourth of the usual amount of nitrate of soda was required. Now, the Gay-Lussac process is not perfect, and probably one-fourth would escape its operation. No decomposition into nitrogen can therefore take place. I have little doubt Mr. Hofmann's first chamber would act by the strong acid at bottom reacting upon his gases, and affording them NO4. I am sorry I cannot as yet give you any decided results as to full success from the adoption of my scheme in its integrity. I only got all the connections made in the end of the week, and to-day my two strong chambers are getting up to the point I shall keep them at, namely, 143° Twad.; but, so far, I see no reason to doubt that at least a considerable saving of nitrate will be effected, and more than the practical trial gave me. probably gave Mr. Hofmann more credit than I should have done, as I never believed his theory; but it was entirely to his suggestion that my effort was due, and in that case I could not claim as an originator, but merely as improving upon a suggestion. I may say that a very large production of acid takes place in my No. 1 chamber; but my No. 2 and 3 also produce largely, and all their production is now going into No. 1 loaded with NO2, and is taken out of No. 1 for use with almost no nitric oxide in it, or not more than I have usually had. If I can effect the expected saving, my only difficulty will be wear and tear of lead.-Yours very truly, (Signed) PETER SPENCE. I MISCELLANEOUS. The Royal Society. The following gentlemen are recommended by the Council for election into the Royal Society, on June 2nd:-William Froude, C.E.; Edward Headlam Greenhow, M.D.; James Jago, M.D.; Nevil Story Maskelyne, M.A.; Maxwell Tylden-Masters, M.D.; Alfred Newton, M.A.; Andrew Noble, Esq.; Captain Sherard Osborn, R.N.; Rev. Stephen Parkinson, B.D.; Captain Robert Mann Parsons, R.E.; William Henry Ransom, M.D.; Robert H. Scott, Esq.; George Frederic Verdon, C.B.; Augustus Voelcker, Ph.D.; Samuel Wilks, M.D. Solar Eclipses.-Through the kindness of Prof. Henry Morton we are enabled to give a brief account of a lecture on the above subject given by him for the benefit of the Franklin Institute. We have before had occasion to refer to the popularity of this eminent lecturer, as well as to the enormous scale on which he conducts the most successful experiments; and the lecture on solar eclipses, which was demanded a second time, illustrated as it was with the most brilliant experiments, fully sustains the high reputation he has gained both in the old and new world. After describing experimentally the causes of an eclipse, the umbra and penumbra, the law of direction, the total eclipse, and the prominences, the lecturer proceeded to illustrate the formation of solar prominences by means of a tank and a coil of wire (see woodcut). The tank is filled with water, and then a solution of cochineal is run in on the bottom with a pipette. A single flask cell excited with bichromate of potash and sulphuric acid is enough to determine the ascending current, which carries up the crimson solution in a very beautiful manner. By interrupting the circuit, the red prominence can be made to settle back, or topple over, so as to assume many of the forms actually observed. To erect the image on the screen, Professor Morton used one of Zentmayer's erecting prisms. Mr. J. N. Lockyer's drawings of solar prominences, pictures of the corona and its coruscation, illustrated by a new piece of apparatus for the lantern, and producing on an immense scale the beautiful effects shown by the chameleon top, were very clearly shown. Existence of Tin in California.-At an exhibition of the agriculture, and manufacturing and mineral resources of California, held last year at San Francisco, sacks of ore, bars of tin-plate, of the heaviest quality, and utensils of every sort for domestic use, which were manufactured from Californian ore, were there collected. Many doubted and shook their heads at this display of a long-desired but unusual manifestation of riches; but, since then, additional information and additional specimens of ore have been forwarded to the United States General Land Office at Washington, and an average sample of the same has been submitted for analysis to the able and distinguished chemist and mineralogist Dr. F. A. Genth, who reports that it contains 13:37 per cent of tin. The black mineral in the ore is tourmaline (it contains boracic acid), and the Journal of the Franklin Institute, vol. liii., p. 407. Comptes Rendus des Séances de l'Académie des Sciences, May 2 1870. This number contains the following original papers relating to chemistry and collateral sciences: Cause of the Electric Currents Produced by the Contact o Metals and Distilled Water.-E. Becquerel. The chief result arrived at by the author's experiments may be summarised thus:The electrical effects produced by the contact of non-oxidisable metals and distilled water (chemically pure) are due, not to any special action of contact, but to the reaction of the water upon the gases condensed on the surface of these metals. The effects vary according to the molecular state of the metals and their temperature. As regards, however, the oxidisable metals, the electrical effects produced by heating them are due to the very slight layer of oxide adhering to their surface, whereby they are rendered positive towards the unpreserved metallic surface. Observations on M. Croullebois's Paper "On the Index of Refraction of Water."-J. Jamin. Reply to the Note of M. Renou "On the Latent Heat of Ice, as Deduced from the Experiments of Laplace and Lavoisier." -J. Jamin. Crystalline Form and Optical Properties of a Combination of Protochloride of Platinum and Triethyl-Phosphine Analogous to Magnus's Salt.-J. des Cloizeaux. Constitution of Luminous Spectra.-Lecoq de Boisbaudran.The author calls attention in this paper to the fact of the analogy which exists between the spectra of the isomeric compounds-for inThe author stance, the alkaline chlorides, bromides, and iodides. three bodies, may be made up, each of which exhibits greater analogy further observes that the following spectral groups, each containing mutually, than with the rest of the groups K Ca CI Rb Sr Br Cs Ba I Researches on the Calorific Spectra.-P. Desains.-Reserved for full translation. Observations on the Results Obtained by M. Croullebois, as regards the Index of Refraction of Water.-A. Cornu. Combustibility of Diamonds, and the Effect of a High Temperature on these Gems.-Prof. Morren.-The author, in a letter, first relates the following facts, as having given rise to his experiments:-A jeweller at Marseilles, an excellent workman, well up to his trade, was requested to enamel afresh the golden bearings of two large diamonds of great value, used as shirt buttons. Instead of taking off the diamonds, always a delicate operation, the jeweller, who had frequently executed such work previously, decided to enamel the gold while the diamonds were left on their bearings. Not happening to have charcoal at hand, the jeweller took coals for heating the muffle for enamelling, an operation which succeeded most perfectly; but, on taking the buttons from the muffle, the jewels had become perfectly black, and no amount of rubbing or friction restored them to their pristine state. The jeweller was, therefore, obliged to dismount the jewels, which looked like plumbago, and to send them to Paris, where, by the beauty, while, curiously enough, their weight had not changed. The first touch of the lapidary's wheel, they became restored to their former author, who, through the kindness of MM. Laurin, jewellers, at Marseilles, was enabled to experiment with several diamonds, placed these high temperature simultaneously with different gases. Heated in coalon a small platinum boat in a platinum tube, and tried the effect of a gas, the gems become blackish, increase in weight, and are found to be coated with a strongly-adhesive layer of carbon, such as is deposited in gas retorts; in pure hydrogen, the gems may be heated almost to the melting-point of platinum without undergoing any change; heated in carbonic acid gas, the gems become dull and lose a little weight 226 Chemical Notices from Foreign Sources. The carbonic acid gas was found to be dissociated into carbonic oxide and carbonic acid; this, the author found, was caused by the platinum and not by the diamond. When the diamond is placed in oxygen gas, and ignited, it continues to burn, but remains white, appearing as a piece of unpolished glass; the stone does not blacken, nor swell up, and, if it is free from flaws or cracks, does not divide asunder. Process Suitable for Estimating the Rapport existing between the Dynamical Force Applied and the Quantity of Electricity Produced in Holtz's Machine.-E. Bouchotte. Solubility of the Chloride, Iodide, and Bromide of Silver in Salts of Mercury.-H. Debray.-The main gist of this paper is, that the insoluble chlorides, iodides, and bromides of silver, and also of mercury, are soluble, to a greater or less extent, in the soluble persalts of mercury, especially at a high temperature, and that, on cooling, some of these haloid salts crystallise; and in that state the chloride of silver perfectly resists the action of light, which the author attributes to the presence of traces of mercury. New Method for the Volumetrical Estimation of Copper.F. Weil. This process is based on the two following facts:-(1) In the presence of free hydrochloric acid, and at a boiling heat, the very slightest trace of bichloride of copper present causes the liquid to assume a very marked yellow-greenish tinge, and this is the stronger the more hydrochloric acid is present. (2) Protochloride of tin causes, at that temperature, the immediate reduction of the salts of oxide of copper dissolved in hydrochloric acid to salts of the suboxide of copper, which, in solution, are absolutely colourless; the reaction takes place according to the formula 2CuCI+ SnCl=Cu2CI+ SnCl2. Any single drop of chloride of tin added in excess may be at once detected by the addition of a drop of a solution of corrosive sublimate (bichloride of mercury), which causes the formation of calomel. If the solution of copper contains iron also, the quantity of chloride of tin applied will indicate the joint quantities of iron and copper present. Products of the Fermentation of Pyro-Tartaric Acid and its Homologues.-A. Béchamp.-Contrary to what, according to the author, might be expected, when pyro-tartaric acid ferments under the influence of the microzymas of chalk-viz., formation of butyric acid according to the formula CHO,2CaO +HO=C,H,O,CaO+CaOCO,+CO, the result obtained by actual experiment is, that no volatile acid is formed at all, and that only carbonate of lime remains; while carbonic acid and marsh gas are given off according to the formula 2(C10H6O6,2CaO)+8HO=5C ̧H ̧+4CaOCO2+6CO2. Preparation of Pyro-Tartaric Acid.-A. Béchamp.-The author first thoroughly deprives of its water of crystallisation the tartaric acid to be submitted to dry distillation, next mixes that material with previously-ignited pumice-stone, and submits that mixture to dry distillation. In this way, 1600 grms. of tartaric acid yield 325 grms. of crude, but crystalline, pyro acid, which is best purified by means of alcohol of 90 per cent. Minerals Found in the Cap Garonne (Département du Var) Copper Mine.-F. Pisani.-Among the many minerals here described the analysis of only one is given-viz., of adamine, a rather rare substance, first discovered in Chili. It consists, in 100 parts, of-Arsenic acid, 38 50; oxide of zinc, 52'50; oxide of cobalt, 3'92; water, 3'57. A cupriferous adamine was found to contain, also, in percentagesArsenic acid, 39:85; oxide of zinc, 3185; oxide of copper, 23'45; oxide of cobalt, o'52; lime, o'87; water, 368. Observations on M. Duclaux's Paper "On the Formation of Drops of Liquids."-Dr. Limouzin. Observations on the Effects of the Aurora Borealis of the 5th of April last on the Telegraphic Wires in the Ottoman Empire. Dr. Lacoine.-The author describes, at length, the very peculiar effects alluded to, which, for a time, made all telegraphy quite impossible, owing to the counter currents excited in, or, at least, conducted by, the wires. Death of Professor Lamé.-At the opening of the meeting, the President announced the death of Prof. Lamé, a member of the Institute since 1843. The deceased, a very celebrated physicist and mathematician, was born in 1795, educated at the Ecole Polytechnique, and was for some time engineer in the Russian service. On his return to France, he was appointed Professor of Physics at the above-named school, and remained in that capacity until the year 1845, when he was elected Examiner of the school. In the year 1848, he was appointed Professor of the Faculty of Sciences at Paris. Among his very many published works, those on mathematics and on the elasticity of bodies are the most celebrated. Revue Hebdomadaire de Chimie, April 21, 1870. Method for Extracting Sugar from Liquids which Contain that Substance, and its Combinations with Saline Matters.M. Lair.-"Suppose," says the author, "any saccharine fluid: I add thereto lime in proper (but not specified) proportions, and heat to a temperature varying from 110° to 159 (under pressure, of course); by which proceeding saccharate of lime is precipitated, which is separated from the fluid either by filtration or decantation, and next treated by the ordinary well-known methods for the extraction of sugar from that lime-compound." Application of Picric Acid for Imparting to Ivory, Bone, and Horn a Beautiful Red Colour.-C. Mène.-After giving a short account of the well-known properties of picric acid, the author de scribes the process alluded to as follows:-"Take 4 grms. of picri acid, and dissolve in 250 grms. of boiling water; add, after cooling CHEMICAL NEWS, 8 grms. of liquid ammonia. Dissolve also 2 grms. of crystallised fuchsine (magenta) in 45 grms. of alcohol, dilute with 375 grms. of hot water, and next add 50 grms. of ammonia. As soon as the red colour of the magenta solution has disappeared, the two solutions are mixed together, making a bulk of liquid amounting to about litre, which is a sufficient quantity for dyeing from four to six sheep's skins. Ivoy and bone should be placed in very weak nitric or hydrochloric acids first, before being immersed in the ammoniacal liquid; wood cannot be dyed by this liquid, unless it has been previously painted over with paste made from flour. When, to the ammoniacal liquid, some gelatine solution be added it may serve as a red ink which does not attack steel pens. By varying the proportions of the magenta and picric acid, the tints obtained may be varied from a bluish red to a bright orange-red. The desired colours do not appear until the ammonia is evaporated. Nickelisation.-M. Gaiffe.-This paper, illustrated by a woodcut, gives practical details about the method applied by the author for the coating of metals with a more or less thick adhesive layer of nickel. Method for Obtaining a Regular Stream of Sulphuretted Hydrogen Gas from Black Sulphide of Antimony.-Dr. Méhu. -In many parts of France, and especially in the south thereof, sulphide of antimony is regularly used for the disengagement of sulphuretted hydrogen; of course, hydrochloric acid and heat have to be applied. In order to obtain a very regular current of that gas, the author advises to mix the pulverised sulphide with about one-third of its weight of quartz sand or powdered sandstone. The addition of this material, in the same proportion, to black oxide of manganese, when used along with hydrochloric acid, for the disengagement of chlorine, has the effect of rendering the evolution of that gas steady while, in both cases, heat may be freely applied to the retorts or flasks without fear of breaking them. Revue des Cours Scientifiques de la France et de l'Etranger This number does not contain any original papers relating to chemistry or physical sciences, but we notice Organisation of Universities.-Dr. Du Bois-Reymond.-A valuable contribution, setting forth what universities ought to be, and how the different systems adopted in France and Germany work for or against the advantage of the students. Asphyxia by Carbonic Vapours.-Dr. Claude Bernard.-An interesting paper in a chemico-legal as well as physiological respect. April 30, 1870. This number does not contain any papers relating to chemistry or physical sciences. Bulletin Mensuel de la Société Chimique de Paris, March, 1870. From the procès-verbaux of the meetings of this Society, published in this number, we abstract the following: M. Fleury stated that he has obtained, from the white-coloured mushroom known as Boletus laricis, two peculiar substances, extracted by means of ether. One of these materials is a brown-coloured resin, insoluble in water, very readily soluble in ether, less so in alcohol of 70 per cent, but very soluble in pure methylic alcohol and chloroform, and insoluble in benzol and sulphide of carbon; this resin is not crystallisable, fuses at 8970, and is soluble in alkalies, from which solution it is precipitated by alcohol; it contains CHO10, and its barium combination is CH,BaO,. The other substance, called agaricie acid, C6H2Os, fuses at 1457, is readily soluble in strong alcohol less so in ether and acetic acid, and very difficultly soluble in water, to which, however, it imparts an acid reaction, perceptible by means of test-paper; this acid forms, with bases, salts; the silver salt is decomposed at 100°. M. Berthelot communicated some of his researches on the oxidation of acetylen and allylen. The oxidising material employed is pure chromic acid free from any sulphuric acid. The energy of the action depends upon the degree of concentration of the chromic acid solution; if that solution is concentrated, formic and carbonic acids are chiefly formed from acetylen; but, if care be taken to cool down the mixture, acetic acid is formed, along with a small quantity of phenaconic acid. Allylen yields propionic acid, and, moreover, a compound containing C,H,Og: The following original papers are published in this number:New Method of Preparing Bromhydric Acid.-Drs. Champion and Pellet.-The authors first state that they tested two samples of bromhydric acid as now met with in commerce. The sp. gr. of one of these samples was 13, and it contained o'3 grm. of real acid to the c.c.; the other sample had a sp. gr. of 112, and was found to contain 0'25 grm. of real acid to the c.c. The process proposed by the authors for the preparation of pure bromhydric acid by a rapid and safe process, is based upon the mutual reaction of the vapours of bromine and paraffin, as already quoted by us from the Comptes Rendus (see CHEMICAL NEWS, vol. xxi., p. 154). Composition of Fossil Bones.-A. Scheurer-Kestner.-This rather lengthy paper contains the results of the author's researches, not simply on the composition of fossil bones, but also on the influence the soil in which they are found may have had in determining their more or less complete petrification. The soil (lehm, a kind of mar!) in which the bones referred to were found was composed, in too parts |