Dr. Kane on a neim class qfPlatina-saJts. 293 



The composition and mode of formation of elaidic acid was 

 undertaken, as his task, by Dr. Meyer. The accurate ex- 

 amination of coccostearic acid (coccinic acid), as well as of 

 the products which originate from the action of nitric acid on 

 fat bodies, was undertaken by M. Bromeis : the composition of 

 the margaric acid in palm oil, and of the acid in cacao butter, 

 by INIr. Stenhouse of Glasgow ; on the composition of the fat 

 substances of the nutmeg butter, and of the wax, by Mr. Play- 

 fair of Calcutta*. 



[To be continued.] 



XLIX. Abstract of the History of a neiso class of Platina- 

 salts, discovered by M. Gros, mtli some Remarks on their 

 true Constitution. By Robert Kane, M.Z)., M.R.I. A.f 



THE very singular substance discovered by Magnus, and 

 formed by boiling protochloride of platina in water of 

 ammonia, is well known to consist of Pt CI -f ^Hg. By this 

 direct process it is formed but slowly and in small quantit}', 

 and a better mode of obtaining it was invented by Liebig. 

 A solution pf perchloride of platina is treated by a current of 

 sulphurous acid gas, until the liquor becomes deep reddish 

 brown, and ceases to precipitate a solution of sal-ammoniac. 

 Being now brought to boil, and water of ammonia being 

 added, Magnus's salt precipitates in fine deep green silky 

 needles. In this way Gros obtained it in quantity sufficient 

 for his researches. 



When this substance Is treated with warm nitric acid it (the 

 acid) becomes brown, and finally converts the salt into a white 

 powder. Red fumes are given off, and generally some double 

 perchloride of platina and ammonium produced, and some 

 metallic platina separated. The white salt is obtained pure 

 by solution in warm water, from which it crystallizes on cool- 

 ing. This salt is colourless, and in brilliant flat prisms. 

 Heated with caustic potash it evolves ammonia, but not 

 otherwise. It is not precipitated by sulphuretted hydrogen. 

 On analysis it yields Pt CI N3 Hy O^. 



• [The autliors had siilijoined to tliis notice of the recent investigations 

 respecting the fatty bodies, particnlars of some of tiieir results ; but as 

 several of the nieiiioirs containing them have now appeared entire in our 

 pages, together with an abstract of otliers, we deem it best to add merely 

 the following references: — An abstract of the researches on the fatty sub- 

 stances by Redtenbaclier, Varrcntrapp, Meyer and Dromeis, was given in 

 the Number for February, jires. vol., p. 1 1;5, preceded, at p. 102, by Dr. L. 

 Playfair's paper on a new fat acid in tiie butter of nutmegs; and in our last 

 number, p. 1 80, appears Mr. Stenhouse s memoir on palm oil and cacao 

 butter. — Kdit.] 



t See p. 284. of the present Number. 



