Dr. Blyth on the Composition of Nareotine. 369 



platinum 0*614 = 22*91 per cent. : from which the calculated 

 atomic weight is 2808*04'. 



II. Ol^t'i grm. of the same preparation gave platinum 0*17 

 =22*88 per cent.; atomic weight=s28l7*17. 



III. 0*997 grm. of a different preparation gave platinum 

 0*23 = 23-06 per cent.; atomic weight = 2773. 



The combustion with chromate of lead gave the following 

 numbers: — 



1*1142 grm. dried at 100° C. gave carbonic acid 1*4055, 

 water 0*334. 



Per cent. 



Carbon =34*4 



Hydrogen = 3*33 



Admitting only one equivalent of nitrogen to be present, the 



formula deduced from these numbers is C25 Hjg NO^;, HCl 



+ Pt CI2, as is apparent from the results calculated and found. 



22*89 22*88 22*91 



5388*5 = atomic weight of the platinum salt. 



Another analysis of this double salt, prepared directly from 

 the base, will be given afterwards. 



From the platinchloride of cotarnin the base can be easily 

 separated by boiling in hydrosulphuret of ammonia. The 

 method I pursued was the following : — The salt was first boiled 

 in ammonia, in which it experienced no change, and while hot 

 acted on by a stream of sulphuretted hydrogen ; decomposi- 

 tion rapidly took place. The residue left, on carefully eva- 

 porating the mixture to dryness on the water-bath, was treated 

 with distilled water, to which hydrochloric acid was added till 

 the reaction was feebly acid, in order to decompose the soluble 

 double salt of bisulphuret of platinum and ammonium formed 

 during the reduction of the platinchloride of cotarnin. On 

 filtering, a fluid passed through of a dark brown colour, from 

 which, on the addition of caustic poiash, the base was preci- 

 pitated. The supernatant fluid, decanted off" and evaporated 

 till no trace of ammonia was left, gave another portion of base 

 which had been held in solution by that alkali. The whole 

 precipitate was again dissolved in dilute hydrochloric acid, 

 boiled with animal charcoal, and after filtration again precipi- 

 tated by potash. 



Cotarnin when pure presents itself in the form of stellated 

 Phil Mag. S. 3. Vol. 25. No. 167. Nov. 1844. 2 B 



