This section is from "Scientific American Supplement Volumes 275, 286, 288, 299, 303, 312, 315, 324, 344 and 358". Also available from Amazon: Scientific American Reference Book.
Chemical Society, London, Jan. 20, 1881. Prof. H.E. Roscoe, President, In The Chair
Mr. Vivian Lewes read a paper on "Pentathionic Acid." In March last the author, at the suggestion of Dr. Debus, undertook an investigation of pentathionic acid, the existence of which has been denied. The analyses of the liquid obtained by Wackenroder and others, by passing sulphureted hydrogen and sulphur dioxide through water, are based on the assumption that only one acid is present in the solution, and consequently do not establish the existence of pentathionic acid; as, for example, a mixture of one molecule of HSO and one molecule of HSO would give the same analytical results as HSO. Moreover, no salt of pentathionic acid has been prepared in a pure state. The author has succeeded in preparing barium pentathionate thus: A Wackenroder solution was about half neutralized with barium hydrate, filtered, and the clear solution evaporated in vacuo over sulphuric acid. After eighteen days crystals, which proved to be barium pentathionate + 3 molecules of water, formed. These crystals were separated, and the liquid further evaporated, when a second crop was obtained intermediate in composition between the tetra and pentathionate. These were separated, and the mother-liquor on standing deposited some oblong rectangular crystals. These on analysis proved to consist of baric pentathionate with three molecules of water. This salt dissolves readily in cold water; the solution is decomposed by strong potassic hydrate, baric sulphite, hyposulphites, and sulphur being formed. By a similar method of procedure the author obtained potassium pentathionate, anhydrous, and with one or two molecules of water. The author promises some further results with some other salts of the higher thionates.
The president said that the society had to thank the author for a very complete research on the subject of pentathionic acid. He, however, begged to differ from him as to his statements concerning the researches of Messrs. Takamatsu and Smith; in his opinion these authors had proved the existence of pentathionic acid. He hoped that the crystals (which were very fine) would be measured.
Dr. Debus said that no one had previously been able to make the salts of pentathionic acid, and expressed his sense of the great merit due to the author for his perseverance and success. The paper opened up some highly interesting theoretical speculations as to the existence of hexathionic acid. If potassium tetrathionate was dissolved in water it could be re-crystallized, but potassium pentathionate under similar circumstances splits into sulphur and tetrathionate; but a mixture of tetrathionate and pentathionate can be re-crystallized. It seemed as if the sulphur when eliminated from the pentathionate combined with the tetrathionate.
Dr. Dupré asked Dr. Debus how it was that a molecule of pentathionate could be re-crystallized, whereas two molecules of pentathionate, which should, when half decomposed, furnish a molecule of tetra and a molecule of pentathionate, could not.
Dr. Armstrong then read a "Preliminary Note on some Hydrocarbons from Rosin Spirit." After giving an account of our knowledge of rosin spirit, the author described the result of the examination of the mixture of hydrocarbons remaining after heating it with sulphuric acid and diluting with half its volume of water and steam distilling. Thus treated rosin spirit furnishes about one-fourth of its volume of a colorless mobile liquid, which after long-continued fractional distillation is resolved into a variety of fractions boiling at temperatures from 95° to over 180°. Each of the fractions was treated with concentrated sulphuric acid, and the undissolved portions were then re-fractionated. The hydrocarbons dissolved by the acid were recovered by heating under pressure with hydrochloric acid. Besides a cymene and a toluene, which have already been shown to exist in rosin spirit, metaxylene was found to be present. The hydrocarbons insoluble in sulphuric acid are, apparently, all members of the CH series; they are not, however, true homologues of ethylene, but hexhydrides of hydrocarbons of the benzene series. Hexhydro-toluene and probably hex-hydrometaxylene are present besides the hydrocarbon, CH, but it is doubtful if an intermediate term is also present. It is by no means improbable, however, that these hydrocarbons are, at least in part, products of the action of the sulphuric acid. Cahours and Kraemer's and Godzki's observations on the higher fractions of crude wood spirit, in fact, furnish a precedent for this view. Referring to the results obtained by Anderson, Tilden, and Renard, the author suggests that rosin spirit perhaps contains hydrides intermediate in composition between those of the CH and CH series, also derived like the latter from hydrocarbons of the benzene series. Finally, Dr Armstrong mentioned that the volatile portion of the distillate from the non-volatile product of the oxidation of oil of turpentine in moist air furnishes ordinary cymene when treated in the manner above described. The fact that rosin spirit yields a different cymene is, he considers, an argument against the view which has more than once been put forward, that rosin is directly derived from terpene. Probably resin and turpentine, though genetically related, are products of distinct processes.
The next paper was "On the Determination of the Relative Weight of Single Molecules," by E. Vogel, of San Francisco. This paper, which was taken as read, consists of a lengthy theoretical disquisition, in which the author maintains the following propositions: That the combining weights of all elements are one third of their present values; the assumption that equal volumes of gases contain equal numbers of molecules does not hold good; that the present theory of valency is not supported by chemical facts, and that its elimination would be no small gain for chemistry in freeing it of an element full of mystery, uncertainty, and complication; that the distinction between atoms and molecules will no longer be necessary; that the facts of specific heat do not lend any support to the theory of valency. The paper concludes as follows: "The cause of chemical action is undoubtedly atmospheric pressure, which under ordinary conditions is equal to the weight of 76 cubic centimeters of mercury, one of which equals 6.145 mercury molecules, so that the whole pressure equals 467 mercury molecules. This force--which with regard to its chemical effect on molecules can be multiplied by means of heat--is amply sufficient to bring about the highest degree of molecular specific gravity by the reduction of the molecular volumes. To it all molecules are exposed and subjected unalterably, and if not accepted as the cause of chemical action, its influence has to be eliminated to allow the introduction and display of other forces."
The next communication was "On the Synthetical Production of Ammonia, by the Combination of Hydrogen and Nitrogen in Presence of Heated Spongy Platinum (Preliminary Notice)," by G. S. Johnson. Some experiments, in which pure nitrogen was passed over heated copper containing occluded hydrogen, suggested to the author the possibility of the formation of ammonia; only minute traces were formed. On passing, however, a mixture of pure nitrogen (from ammonium nitrite) and hydrogen over spongy platinum at a low red heat, abundant evidence was obtained of the synthesis of ammonia. The gases were passed, before entering the tube containing the platinum, through a potash bulb containing Nessler reagent, which remained colorless. On the contrary, the gas issuing from the platinum rapidly turned Nessler reagent brown, and in a few minutes turned faintly acid litmus solution blue; the odor of NH was also perceptible. In one experiment 0.0144 gramme of ammonia was formed in two hours and a half. The author promises further experiment as to the effect of temperature, rate of the gaseous current, and substitution of palladium for platinum. The author synthesized some ammonia before the Society with complete success.
The President referred to the synthesis of ammonia from its elements recently effected by Donkin, and remarked that apparently the ammonia was formed in much larger quantities by the process proposed by the author of the present paper.
Mr. Warington suggested that some HCl gas should be simultaneously passed with the nitrogen and hydrogen, and that the temperature of the spongy platinum should be kept just below the temperature at which NH dissociates, in order to improve the yield of NH.
"On the Oxidation of Organic Matter in Water" by A. Downes. The author considers that the mere presence of oxygen in contact with the organic matter has but little oxidizing action unless lowly organisms, as bacteria, etc. be simultaneously present. Sunlight has apparently considerable effect in promoting the oxidation of organic matter. The author quotes the following experiment: A sample of river water was filtered through paper. It required per 10,000 parts 0.236 oxygen as permanganate. A second portion was placed in a flask plugged with cotton wool, and exposed to sunlight for a week; it then required 0.200. A third portion after a week, but excluded from light, required 0.231. A fourth was boiled for five minutes, plugged, and then exposed to sunlight for a week; required 0.198. In a second experiment with well water a similar result was obtained; more organic matter was oxidized when the organisms had been killed by the addition of sulphuric acid than when the original water was allowed to stand for an equal length of time. The author also discusses the statement made by Dr. Frankland that there is less ground for assuming that the organized and living matter of sewage is oxidized in a flow of twelve miles of a river than for assuming that dead organic matter is oxidized in a similar flow.--Chem. News.