July 3. 1879] 



NATURE 



235 



thought it very advisable to inquire on what terms these metals 

 might prove to be mutually equivalent : and the particular equi- 

 valence they have examined lias been equivalent precipitability 

 of the sulphates, by sodic hydrate, from an aqueous solution. 



After describing the mode of preparation of the pure sul- 

 phates, the authors give an experimental criticism of the methods 

 of separating nickel from cobalt, finally adopting the one devised 

 by Gibbs. Having then fixed on the method of separation, I 

 per cent, solutions of nickelous and cobaltous sulphates were 

 prepared, and a solution of sodic hydrate, of which 10 cub. 

 centims. were capable of precipitating •824S grm. of nickelous 

 or cobaltous sulphate. This sodic hydrate was made from 

 sodium, and kept in glass bottles coated internally with a thick 

 layer of paraffin. 



A series of nine experiments was made, in which the relative 

 weights of nickelous or cobaltous sulphate prepent, varied from 

 •I to '9 grm. ; the total weight of nickelous and cobaltous salt, 

 and the volume of the solution being, however, always the same, 

 viz., I grm. and lOO cub. centims. The experiments were con- 

 ducted as follows : — The bottles containing the solutions of the 

 sulphates and the sodic hydrate were immersed in a trough into 

 which there was a constant flow of water to bring them to a 

 constant temperature. The necessary quantities of nickelous 

 and cobaltous solutions v.-ere then carefully measured out, mixed, 

 and the temperature observed. 10 cub. centims. of sodic hydrate 

 was then added, the solution stirred vigorously, and the tempera- 

 ture again observed. The precipitate was then filtered off as 

 quickly as possible (an aspirator being used to facilitate the filtra- 

 tion), and washed, first with cold and then with hot water. It 

 contained sodic sulphate, cobaltous sulphate and hydrate, and 

 nickelous hydrate, all of which were analytically determined. 



If « represent a weight of nickelous sulphate taken, and v be 

 the hydrate (calculated to sulphate) obtained from it tlirough 

 precipitation, the experiments show that n — {\ -^ '21940 «) v. 

 Similarly, for cobalt, c = fi84S/. The authors give the fol- 

 lowing conclusions as the result of a discussion of their work : — 

 ( I ) The precipitability of nickelous sulphate is directly proportional 

 to its mass; (2) Tlie precipitability of cobaltous sulphate is an in- 

 variable quantity ; (3) For an equal weight nickelous and cobaltous 

 sulphates are equally precipitable ; the attraction of the one towards 

 the reagent being then inverse to that of the other. 



They accordingly write <(> (NiS04) = (ij> CoSo4)-i. 



"On the Formation of Hydrocyanic Acid in the Electric 

 Arc." By James Dewar, M.A., F.R.S., Professor of Chemistry 

 to the Royal Institution. 



The inference drawn from experiments given in the paper is 

 that the reaction is in all probability the result of acetylene re- 

 acting with free nitrogen, as when induction sparks are passed 

 through the mixed gases, viz. — 



CjHj -H N2 = 2HCN, 



and that the hydrogen is obtained from the decomposition of 

 ! aqueous vapour, and the combined hydrogen in the carbons. It 



is possible, traces of alkaline salts in the carbon poles may 

 ; favour the formation of hydrocyanic acid, but, as all attempts to 

 \ purify the poles so as to stop the reaction failed, I am inclined 

 I to Ijelieve it is a direct synthesis. The acetylene reaction is one 

 I of the many remarkable syntheses discovered by Prof. Berthelot 

 ; of Paris. The presence of sulphuretted hydrogen is doubtless 



due to the reduction of the sulphates, invariably present in the 



asli of the carbon. 



"An Account of Experiments on the Influence of Colloids 



upon Crystalline Form, and on Movements observed in Mix- 



' tures of Colloids with Crystalloids." By William M. Ord, 



, M.D. Lond., F.L.S. Communicated by T. Simon, C.B., 



i D.C.L., F.R.S. 



" Chemical Society, June 19.— Dr. Roscoe in the chair.— The 

 . following papers were read : — On Gardenin, by Dr. Stenhouse 

 . and Mr. C. E. Groves. This substance has been extracted from 

 j "Dekamali gum," the resin of the Gardenia lucida. Gardenin 

 j fay treatment with nitric acid is converted into a mass of red 

 \ crystals of gardcnic acid ; an acetyl derivative has been obtained. 

 I Gardcnic acid in contact with sulphurous acid is converted into 

 ) hydrogardenic acid. — On dry copper-zinc couples and analogous 

 I agents, by Dr. J. H. Gladstone and Mr. A. Tribe. By heating 

 I nine parts of coarse zinc filings with one part of finely divided 

 ; copper in a flask over a Bunsen flame until the filings begin to 

 , lose their shape, dark grey granular masses are obtained. These 

 I masses constitute the d-y copper'zinc couple, which is found to 



equal in activity the well-known moist copper-zinc couple, 

 prepared by immersing zinc foil in copper sulphate solution ; ten 

 grammes of the dry couple convert 5 cc. of ethyl-iodide into 

 zinc ethiodide in about six minutes. Couples of other metals 

 were tried, but none were found to be in practice .superior to that 

 formed of copper and zinc. — On the action of sulphuric acid on 

 the hydrocarbons of the formula Ci„Hi5, by Drs. Armstrong and 

 Tilden. The authors deny the statement made by Ribau that 

 the product of the above action yields a distillate when steam is 

 passed through it consisting of cymene with a liquid isomeride of 

 terpene ; the so-called terebene is really inactive camphene, 

 melting at 47°. The crude colophene remaining after the distil- 

 lation in .steam yields on distillation 10-30 per cent, of volatile 

 substances — inactive camphene, terpilene, a paraffin-like body, 

 an optically inactive camphor, &c. — Researches on the 

 terpenes, camphor, and allied compounds, by Dr. Armstrong. 

 Part I. On hydrocarbons associated with the terpenes, and on the 

 formation of cymene from terpenes and allied compounds. II. 

 On the action of iodine on terpenes. HI. Camphor derivatives. 

 — Contributions to the history of starch and its transformations, 

 by Messrs. H. F. Brown and Heron. The authors have 

 examined in a most elaborate manner the action of malt extract 

 at various temperatures and under varied conditions, on potato 

 starch. — On the determination of nitric acid by means of 

 indigo, with especial reference to water analysis, by Mr. R. 

 Waring:ton. The author gives the results of much experience 

 with this process, which has the advantages of great simplicity, 

 speed, and delicacy ; the results are, however, conditioned by 

 many circumstances which must be known before the method can 

 be appUed with delicacy.— Notes on the purple of the ancients, 

 by Dr. E. Schunck. The author has worked up about 400 

 specimens of Purpura Icpillus, a shell-fish found at Hastings, 

 and extracted the cyst ccntaining the yellowish secretion which 

 in sunlight becomes purple and forms a permanent dye stuff. 

 The colouring matter apparently belongs to an unknown member 

 of the indigo-bh-e group. — On the heat of formation of aniline, 

 picoline, tuluidine, lutidine, pyridine, dipicoline, pyrrol, glyce- 

 rine, furfurol, by W. Ramsay.— On ethylenic chlorosulpho- 

 cyanide and its oxidation into ethylenic chlorosulphonic acid, by 

 J. W. James. — On mixing and heating potassium sulphocyanide 

 with alcohol and chlorobromide of ethylene, potassium bromide, 

 and chlorosulphocyanide of ethylene were obtained. The latter 

 with nitric acid gave chloroethylene sulphonic acid, the silver salt 

 of which heated with ammonia furnished taurin. — On the boiling 

 points of certain metals and metallic salts, by Dr. T. Carnelly 

 and Dr. W. Carleton Williams. 



Linnean Society, June 19.— Prof. AUman, F.R.S., pre- 

 sident, in the chair.— Attention was called to two volumes folio 

 on the British fresh water fishes by the Rev. W. Houghton. 

 These, recently issued, illustrate in colours all the known and new 

 species. — The Secretary read a paper on a remarkable branched 

 Syllis from the Challenger expedition, by Dr. W. C. Mcintosh. 

 This Polychaste w orm .S'. ramosa was got in the basal canals of 

 a hexactinellid sponge, dredged near Zebu, Philippines. 

 Thread-like in thickness, the branches are intricately arranged 

 among the meshes of the sponge, and it appears that but 

 one head must serve for many branches. Buds and second- 

 ary buds are very numerous on the latter, and in a free 

 female pedal bristle-tufts were observed. A fragment of a dif- 

 ferent form is suggested, as possibly the male of the foregoing 

 rare example of a truly branched annelid, differing in most par- 

 ticulars fro 1 anything heretofore recorded. — There followed 

 remarks on Carpesium (C.cernuum) as indigenous to Australia, 

 by ¥. M. Bailey. The author supports Mr. Bernay's view of 

 this plant not being introduced, but undoubtedly endemic. — Mr. 

 A. Hammond read a paper on the thorax of the blowfly. Most 

 authorities at present recognise the great preponderance of the 

 mesothorax over the other two segments, but do not fix the 

 limits of each. The author refers to the integumentary parts 

 entering into the thorax of insects, as enumerated by Audouin, 

 and also es| ecially to the views held by Westwood, Burmeister, 

 Lowne, and others. Afterwards he gives a full description 

 of his own dissections and preparations, and reasons for dissent 

 from the majority of workers, though with evident inclination 

 to Audouiu's opinions. He concludes that, from the analogy 

 presented by oiher insects, from the evidence derivable from the 

 phenomena of developmental change, and from a study and 

 consideration of the nervous and muscular systems all combine 

 to show that the thorax of the Dipteni, as illustrated in the 

 blowfly, is almost exclusively mesothoracic, a conviction quite at 



