22 PROCEEDINGS OF THE AMERICAN ACADEMY 



cobalt, and also by the action of the alkaline oxalate upon the nitrate 

 of the same base. When the neutral oxalate is boiled with an excess 

 of oxalic acid, the solution deposits, on cooling, fine garnet-red crusts of 

 crystals resembling prehnite in appearance. This salt is the acid 

 oxalate of roseocobalt, and has the formula, — 



Co,(NH3),,(C,OJ3+4C,H,0„ 

 as the following analyses show : * — 



1. 0-4897 gr. gave 0-1C73 gr. SO,Co= 13-OOr^ cobalt. 



2. 0-3421 gr. gave 0-0447 gr. cobalt = 13-06^ cobalt. 



3. 0-8908 gr. gave 0-5913 gr. Co^ and 0-3389 gr. water =: 18-10% 



carbon and 4-22% hydrogen. 

 4 M337 gr. gave 0-74G0 gr. Co^ and 0-4439 gr. water = 18-03% 



carbon and 4-35% hydrogen. 

 5. 0-7397 gr. gave 0-4872 gr. Co^ and 0-2922 gr. water = 17-96% 



carbon and 4-19% hydrogen. 



Cobalt, 

 Carbon, 

 Hydrogen, 



The formula appears, when compared with tho«e of the ordinary 

 double oxalates containing metallic sesquioxides, to be abnormal ; but 

 the analyses made with carefully recrystallized, pure, and homogene- 

 ous salt seem to leave no reasonable doubt as to the true constitution. 

 Oxalo-platino-chlorlde. — When a solution of chlorplatinate of so- 

 dium, PtCl^Nag, is added to one of the neutral oxalate of roseocobalt, 

 a fine red crystalline precipitate forms after a short time, which may 

 be jjurified by a second crystallization. The salt forms small grouped 

 acicular crystals, which have a rather pale-red color. It is somewhat 

 easily soluble in cold water. Boiling water dissolves it readily, form- 

 ing a clear red solution, fi-om wliich the salt crystallizes without de- 

 composition. The formula of this salt is, 



Co,(NH,),„(C,OJ,Cl,+PtCl„ 

 as the following analyses show : — 



0-5389 gr. gave 0-1210 gr. platinum and 0-4002 gr. silver = 22-45% 



platinum and 24-41 % chlorine. 

 The formula requires 22-62% platinum and 24-34% chlorine. 



* My friend and former pupil, Prof. Sadtler, had the kindness to make 

 analyses 4 and 6 for me after my own laboratory had been closed. I deemed 

 them necessary to verify the unexpected formula. 



