18 PROCEEDINGS OF THE AMERICAN ACADEMY 



The formula Co^CNHJioClg+SrtCl.+SOH^ requires : — 



These analyses were not published in the first part of this paper, be- 

 cause Genth and I did not succeed in pre^^aring the salt a second time. 

 ] do not myself consider them — in spite of their close agreement with 

 the formula given — sufficient to establish the existence of the salt in 

 question. Further researches may be more successful in this respect. 

 Sidphato-chlorplatlnate. — When chlorplatinate of sodium is added 

 to a solution of the soluble sulphate of roseocobalt, a beautiful bright- 

 red crystrdline salt is precipitated, which is but slightly soluble in cold 

 water, but which may be dissolved in a very large excess of boiling 

 water with a few drops of free acid, and crystallizes from the solu- 

 ticm without decomposition. This salt has the formula, — 



Co,(NH3),,(SOJX],+PtCl„ 



as the following analyses show : — 



0-4806 gr. gave 0-3476 gr. silver = 23-78^^ chlorine. 



0-4-2-21 gr. gave 0-1505 gr. platinum and cobalt :^ 35-65^. 



0-1428 gr. of the mixed metals gave 0-0898 gr. platinum = 22-43% 



(of the salt), and 13-22^ cobalt (by difference). 

 0-5219 gr. gave 0-2618 gr. SO.Ba = 20-669/^80,. Salt fused with 



COgKNa. 



The salt lost no water on being heated to loO^C. The formula re- 

 quires : — 



A solution of the yellow modification of the sulphate of roseocobalt 

 already described, gave with chlorplatinate of sodium a beautiful vel- 

 low crystalline precipitate remarkably insoluble even in hot water. 

 Tliis salt, after washing and drying in pleno over sulphuric acid, was 

 analyzed : — 



0'4202 gr. ga^^e 01488 gr. platinum and cobalt = 3541 r^. 



