816 Mr. C. 6. Williams on the presence of Pyridine in 



The alkaloids were chiefly separated from each other by frac- 

 tional distillation, but the more volatile of them were present in 

 too small a quantity to render this method applicable ; I there- 

 fore availed myself of the platinum-salts as a means of purifica- 

 tion, and on adding a strong aqueous solution of chloride of 

 platinum to a solution of the first fraction in hydrochloric acid, 

 a preci})itate was obtained, which on combustion gave exactly the 

 composition of picoline. But the fraction from which this re- 

 sult was obtained, distilled below and at 210° Fahr., while the 

 boiling-point of picoline, according to Anderson, is 272°; I there- 

 fore suspected the presence of a more volatile base, but was pre- 

 vented by deficiency of material from pursuing the investigation 

 further. 



Having since that time obtained another small quantity of 

 liquid from the same source and boiling at the same temperature, 

 I availed myself of the opportunity of studying the separation 

 of bases by fractional crystallization of platinum-salts. 



The basic oil, amounting to about three-fourths of a drachm, 

 was supersaturated with hydrochloric acid, an aqueous solution of 

 chloride of platinum added, and the whole diluted until the pre- 

 cipitate at first formed was redissolved; the liquid was then 

 allowed to crystallize spontaneously, and at the end of three 

 days yielded a considerable crop. 



On examination these were found to consist of two sorts, a and 

 b ; the former had assumed the shape of sword-blades of a pale 

 yellow colour, and more than half an inch long; b, on the other 

 hand, formed small flattened four-sided prisms, very thick in pro- 

 portion to their length, and of a deep ruby-red. It was, of 

 course, supposed that the salts of two bases had crystallized in the 

 same liquid, but on careful ignition the following numbers were 

 obtained : — 



J fa. 4-707 grs. gave 1*482 platinum. 

 \b. 6022 grs. gave 1-910 platinum. 



Per cent. 

 a. b. Theory {lutidine). 



31-48 31-70 31-51 



We therefore see that both salts had the same composition, 

 but the anomaly in the^. boiling-point, and the difi*erence in the 

 appearance of the ci-ystals, renders the opinion probable that 

 two bases are present, bearing the same relation to each other 

 that picoline does to aniline. 



Recent researches having shown the constitution of platinum- 

 salts to be remarkably modified by the action of heat upon their 

 solutions, the evaporations in these experiments were made by 

 exposing them to a surface of sulphuric acid until a crop was 

 obtained, which was then removed and the operation repeated. 



