CHEMISTRY. Address by W. A. MILLER, M.D., F.R.S. &c., Professor of Chemistry, King's College, London. IN opening the proceedings, the President said that in the home of Dalton, in the focus of applied chemistry, very few words would be necessary. They could not but remember that, on the last occasion when the Meeting of the British Association was held in Manchester, that illustrious philosopher was still amongst them; and he trusted that the same spirit which actuated Dalton still remained in Manchester to enlighten his native county. Without saying more by way of introduction, he would call their attention to one or two points of progress during the past year. In calling attention to these subjects, he must necessarily refer to debatable ground in science, but it was in debatable land that progress was necessarily made. He would only touch upon two or three practical applications of chemistry, and two or three theoretical ideas which had been propounded since they last met. The Professor then alluded to the new methods of preparing oxygen and hydrogen, proposed by Deville, which admit of application on such a scale as to allow of the generation of oxygen for manufacturing purposes, and the employment of the oxyhydrogen blast as a source of heat in metallurgical operations. The novelty in the preparation of oxygen consists in decomposing the vapour of sulphuric acid, and, by a further process, storing up the oxygen in gas-holders. The preparation of hydrogen required more care. The metallurgy of platinum had already experienced a remarkable modification, owing to the application of the intense but manageable source of heat obtained by the combustion of these gases. In connexion with oxygen might be mentioned a singular circumstance regarding ozone, which, according to the observation of Schrötter, had been found in a peculiar species of fluor spar, from Wolsendorf, which, when rubbed or broken, emitted a peculiar odour of ozone. The active chemist Deville, in following his researches, had discovered a variety of means of obtaining artificially, crystallized minerals of great regularity and beauty. The methods adopted were chiefly by heating the amorphous substances in a slow current of some gas, such as hydrochloric acid, which was not an unfrequent natural product in volcanic districts. No discovery, however, had made a greater impression upon the popular mind than that of the remarkable alkaline metals cæsium and rubidium by Kirchhoff' and Bunsen. These eminent men, in investigating the appearances presented by flames coloured by various metallic salts when analysed by the prism, were led, from the appearance of certain bright lines in the spectra, produced whilst they were examining a saline residuum from the waters of the Dürkheim spring, to infer the existence of a substance hitherto unknown. It was found that cæsium was present in such minute quantity, that a ton of that water, which was the most abundant source of caesium yet known, contained only 3 grains of its chloride. Taking into account the minuteness of the quantity, and its striking resemblance to potassium, it was not too much to say that the discovery of caesium would have been impossible by any other known method than that which was actually employed. The other metal, rubidium, was somewhat more plentiful; but rubidium also so closely resembled potash that it would not have been discovered but for the peculiarity of its spectrum. Referring to the revision of the atomic weights of sulphur, silver, nitrogen, potassium, sodium, and lead, by Stas, Professor Miller said that chemist had come to the conclusion that it was not proved that the elementary bodies were multiples of the unit of hydrogen, and, in opposition to the opinion of Dumas, he had pronounced the law of Prout as imaginary. Every chemist would read with interest the paper by Graham upon the application of liquid diffusion to analysis. The remarkable conclusion to which the author arrived was, that the process of diffusion separated all substances into one or other of two classes, which he distinguished as crystalloids and colloids. The rapid improvement in the method of analysis, though not admitting on that occasion of detailed mention, must not be overlooked. A variety of bodies, formerly supposed to be of rare occurrence, were now found in minute quantities, unexpectedly, but widely diffused. The discovery of these small quantities was by no means unimportant, for they might aid in solving problems of great interest. Glancing only for a moment at the important practical subject of the formation of steel, Professor Miller referred to the activity employed in the pursuit of the organic department of chemical science; remarking upon two lines of research as important from their theoretical bearings, namely the investigation of polyatomic compounds, and the process of oxidation and of reduction, applied by various chemists, and by Kolbe in particular, to the investigation of the organic acids. The labours of Hofmarm upon the polyatomic bases showed completely the principle upon which these bodies might be formed, and he had been enabled to group an unlimited number of atoms of ammonia into one compound molecule. Great progress had also been made in our knowledge of the relations of the organic acids." On the Constitution of Paranaphthaline or Anthracene, and some of its Decomposition Products. By Professor ANDERSON, F.R.S.E. 10° The author, after referring to the previous investigations of Laurent and Dumas, which indicated the isomerism of naphthaline and anthracene, detailed the results of his own researches, which have established for the latter substance the formula CH Anthracene, when treated with nitric acid, undergoes a decomposition entirely different from that of naphthaline under similar circumstances, and yields an oxidized compound, oxanthracene, C, H, O, which is volatile without decomposition, and crystallizes in fine needles of a pale buff colour. Bromine gives C24 H Bre in small hard crystals apparently rhombohedral, which when digested with alcoholic potash give C, H, Br, in fine sulphur-yellow crystals. Chlorine gives C, H, Cl, and this with alkalies yields C, II, Cl. 10 10 These and other details contained in the paper show that anthracene is not isomeric with naphthaline, but they connect it with the benzoyl series, and more especially with stilbene, from which it differs by H2; while oxanthracene and benzil are similarly related to one another, as shown by the following comparison of their formulæ : Anthracene C23 H10 Oxanthracene 28 8 The author proposes to prosecute the investigation of these relations. On the Effect of Great Pressures combined with Cold on the Six Noncondensable Cases. By Professor ANDREWS, M.D., F.R.S. In this communication the author gave an account of some results already obtained in a research with which he is still occupied on the changes of physical state which occur when the non-condensable gases are exposed to the combined action of great pressures and low temperatures. The gases when compressed were always obtained in the capillary end of thick glass tubes, so that any change they might undergo could be observed. In his earlier experiments the author employed the elastic force of the gases evolved in the electrolysis of water as the compressing agent, and in this way he actually succeeded in reducing oxygen gas toth of its volume at the ordinary pressure of the atmosphere. He afterwards succeeded in effecting the same object by mechanical means, and exhibited to the Section an apparatus by means of which he had been able to apply pressures, which were only limited by the capability of the capillary glass tubes to resist them; and while thus compressed the gases were exposed to the cold attained by the carbonic acid and ether bath. Atmospheric air was compressed by pressure alone to of its original volume, and by the united action of pressure and a cold of — 106° F. toth, in which state its density was little inferior to that of water. Oxygen gas was reduced by pressure to th of its volume, and by pressure and cold to th; hydrogen by the united action of cold and pressure to th; carbonic oxide by pressure to 4th, by pressure and cold to th; nitric oxide by pressure to th, by pressure and a cold of-160° F. to th. None of the gases exhibited any appearance of liquefaction even in these high states of condensation. The amount of contraction was nearly proportional to the force employed, till the gases were reduced to from about 6th to 16th of their volume; but, beyond that point, they underwent little further diminution of volume from increase of pressure. Hydrogen and carbonic oxide appear to resist the action of pressure better than oxygen or nitric oxide. 4 On the Chemical Composition of some Woods employed in the Navy. The author thought that it might prove interesting to ship-builders if he were to investigate the chemical composition of the various woods employed in the Navy; especially when this important adjunct of England's wealth is undergoing such extensive modifications, and when it is of such paramount importance to know which is the best wood to be used in the construction of the new iron-plated frigates. He had examined ten different woods, and the superiority of some foreign woods over English oak could not be too strongly expressed. If English oak has hitherto stood so high, it must have been owing to our ignorance of the valuable properties of some of the woods grown in tropical climates, in which the soluble and highly decomposable tannin of oak is replaced in some instances by resins, and in others by substances similar to caoutchouc. This is the case with Moulmein teak, Santa Maria, Moira wood, and Honduras mahogany, which gives to them a great advantage over oak for iron ship-building. Thus he has found that in the same time, and under similar circumstances, oak will attack iron twice and three times as rapidly as the woods above-mentioned. He has also remarked that if cubes of the same dimensions of the various kinds of wood remain in contact with water for five months, they lose respectively the following per-centages of their substance --Unseasoned oak, 24; seasoned oak, 12; African teak, 3; Moira wood, 4; Honduras, 3; Santa Maria, 16; Greenheart, 56; Moulmein teak, 17. The facility of mildewing or decaying is as follows:-Unseasoned oak, rapid; seasoned oak, much less; African teak and Honduras mahogany, limited; Moira wood, Santa Maria, and Moulmein teak, none. For further details Mr. Crace Calvert would avail himself of an early opportunity of publishing a complete paper; but there was one point which he deemed it his duty to mention at once. During his researches he had found a great difference between oak felled in summer and that felled in winter, viz. that the oak felled in winter was rich in tannin, while the oak felled in summer contained little or no tannin, but a large quantity of gallic acid; and on examining some specimens of wood from unsound gun-boats furnished to him by some of Her Majesty's Officials, he found that the chemical composition of the wood of the sound gun-boat was identical with that of well-seasoned oak, while the composition of the wood of the unsound gun-boat was identical with that of unseasoned summer-felled oak. On the Chemical Composition of Steel. By Dr. CRACE CALVERT, F.R.S. The author entered into some detail respecting the interesting discussion which has lately taken place before the French Academy of Science, between MM. Fremy and Caron, on the chemical composition of steel, the former contending that nitrogen is essential to the conversion of iron into steel, the latter that carbon alone is sufficient to effect that object. But an observation that Mr. Crace Calvert has made, tends to show that the molecular condition of steel has a great deal to do with the nature of its chemical composition; for if a piece of soft steel be divided into two portions, and one of these is hardened or highly tempered, the slow action of acetic acid proves to be quite different; and whilst soft steel is scarcely acted upon by weak acetic acid, hard steel is rapidly dissolved. Further, the soft steel leaves a homogeneous grey carburet of iron, similar in its texture to the graphitoid compound lately described by him (Mr. Calvert), whilst that of tempered steel is black, possesses no cohesion, and has the appearance of pure carbon. On the Evolution of Ammonia from Volcanos. By Professor DAUBENY, M.D., F.R.S. This phenomenon had been ascribed by Bischof to the decomposition of bituminous matters by volcanic heat; by Bunsen to the lava flowing over herbage, and disengaging its nitrogen, which exhibited itself in the form of ammonia; and on former occasions, by the author of this paper, to the direct union of hydrogen and nitrogen in the interior of the earth under an enormous pressure. Now, however, that Wöhler has shown the affinity which subsists between nitrogen and certain of the metals and simple combustibles, some of which, as titanium or boron, combine with it directly with such avidity that the union is attended with combustion; and that he has also proved the nitrides formed to be decomposed by the hydrated alkalies, ammonia being thereby generated,—it has occurred to the author that a more probable explanation of the occurrence of ammonia in volcanos might be afforded by supposing such combinations to take place in the interior of the earth, and there to be subsequently decomposed by the alkalies which are usually present wherever volcanic action is taking place. In confirmation of this view, he appealed to a late observation made by Signor Guiscardi, a distinguished naturalist at Naples, namely, that metallic titanium was found to be evolved from the crater of Vesuvias during a late eruption. On a particular Decomposition of Ancient Glass. By H. DEANE. The author's object was to show, first, that an incrustation observed within a glass ampulla from the ancient Christian catacombs of Rome was not organic matter, as had been supposed; and secondly, that it was the result of a decomposition of the glass itself, probably originally coloured with peroxide of iron. This in the course of time had separated, like the other ingredients of the glass, and found its way to the surface in a spheroidal and arborescent form, similar to what may be observed in moss agates. That it was not a mere extraneous deposit was obvious from the fact of its being chiefly in the substance of the glass itself, and nearly equally distributed on both inner and outer surfaces. He had observed precisely the sare condition in some ancient glass from Nineveh. On Morin, and the non-existence of Morotannic acid. By Dr. DELFFS. M. Wagner published in the year 1850 an investigation on the wood of Morus tinctoria, and stated that this wood contains two peculiar and isomeric matters, morin and morotannic acid, the latter of which differs from all other tannic substances by being able to crystallize. Since that time no other chemist has discussed the same subject. The author thought, therefore, a repeated investigation on morin and morotannic acid would not be superfluous, and found that morotannie acid is only morin in an impure state, and that an often-iterated crystallization suffices to convert it into a white substance possessing all the properties of pure morin. The composition of morin corresponds to the formula CH 0+2HO. M. Wagner gives the formula C18 H 010 Morin most resembles catechin: it gives, when heated above its melting-point, pyrocatechic acid; the colour produced in the solution of catechin by chloride of iron is nearly identical with that which is caused by the same test in the solution of impure morin; and a comparison of the composition of catechin, which Dr. Delfis found seventeen years ago (Jahrbuch für praktische Pharmacie, vol. xii. p. 162), and that of morin will show that the difference between both is not very great. The author tried, therefore, to convert catechin by repeated crystallization into morin, but without result, and he is quite convinced that these two substances are not identical. On Piperic and Hydropiperic Acids. By G. C. FOSTER, B.A., F.C.S. The analysis of piperic acid and of the piperates of potassium and barium led to the formula C12 H10 O4* for the acid, and to the formula C12 H MO1 for the salts; thus confirming Strecker's formule t. A warm aqueous solution of piperate of potassium is converted, by treatment with sodium-amalgam, into hydropiperate of potassium. Hydropiperic acid melts to a transparent oil under hot water, and dissolves in all proportions in alcohol: it contains C13 H12 O4. The following hydropiperates were analysed : Hydropiperate of ammonium ...... * C=12, H=1,0=16. C12 H (NH) O'. C12 H11 CaO (at 100°). C112 H11 AgO1. † Ann, Chem. Pharm. cv. 317. On the Composition and Valuation of Superphosphates. On an Aluminous Mineral from the Upper Chalk near Brighton. In an old chalk-pit at Hove there are many faults, and some of these are filled up with a white soft mineral that runs along the broken layers of flint and imbeds the fragments. It appears in agglomerated masses, which easily fall to powder, and are porous. Sp. gr. 1.99. One piece that was analysed proved to be the hydrated disilicate of alumina, that has received the name of Collyrite, with no other impurity than one per cent. of carbonate of lime. Another piece contained 13 per cent. of carbonate of lime, and 5 per cent. additional of carbonic acid, which was supposed to be combined with alumina. As the silicic acid was proportionally smaller in quantity, this piece was viewed as collyrite in which about half the silicic acid had been replaced by carbonic acid. On the Emission and Absorption of Rays of Light by certain Gases. This communication arose out of an attempt to determine what constituents of the air give rise to the "atmospheric lines" of the solar spectrum, of which a map had been exhibited by the author at the Leeds Meeting of the Association, and which had been since published in a more complete form by Sir David Brewster and himself. A comparison of the bright rays emitted by nitrogen, oxygen, hydrogen, carbonic acid, and water, when strongly heated, had shown that they do not coincide with the absorption-bands of the atmosphere. It is possible that the three bright lines of the hydrogen spectrum, as given by Angström and Plücker, may be in the same position as C1, F, and p of the atmospheric spectrum. Yet the author inclined to the belief that these absorption-bands are due to two or more different constituents in varying proportions, more abundant in some places than in others, and probably in very minute quantities. The following facts were mentioned among others :-The flame of carbonic oxide burning in air gave a continuous spectrum from about C to about k, where it ceased rather abruptly: it was without either bright or dark lines. The alcohol flame shows four bands-the first faint in the yellow, nearly midway between D and E; the second brighter, green, just beyond b, with the refractive index 1.6254 for glass, which gives as the refractive index of b 1.6249; the third faint and blue, about half-way between F and G; the fourth a more luminous double line, violet, with the refractive index 1.6413, that of the line G being 1.6404. The oxyhydrogen flame gave a continuous spectrum principally green and blue, extending to about G 33, with no lines corresponding to the hydrogen lines of Angström and Plücker. The lightning flash gave a continuous spectrum, showing all the colours from red to violet, with doubtful indications of more luminous bands. That there is no necessary correspondence between the lines of absorption of a gas at the ordinary temperature, and the rays emitted by it at a high temperature, is strikingly proved by iodine, where the absorption-bands delineated by Professor Miller, the groups of green and blue bands produced when the vapour is introduced into a Bunsen's flame, and the lines of the rarefied gas as observed by Plücker, are perfectly dif ferent. By the prismatic analysis of solar light, the absence of the coloured gases from the air can be proved, even in very minute quantity. Thus the author observed that about th of an inch of bromine vapour interposed between the eye and the object-glass of the refraction goniometer was sufficient to exhibit the absorption-bands; and from this he had reckoned that if free bromine constituted one thousand millionth part of the atmosphere, it would betray its presence in the solar spectrum when the sun was on the horizon; but there is no such indication. This, however, rests on the unproved assumption that a gas almost infinitely diffused along a given line will produce the same absorbent effect as if its particles were all close together at some point along that line. |