92 W. Gihhs and F. A. Genth 



orange-redj corresponding nearly with tlie red-orange No. 5, of 

 the 2d circle of Chevreul's scale. When freshly prepared, it is 

 one of the most beautiful salts which chemistry can exhibit, but 

 it loses some of its brilliancy of tint by keeping, and becomes a 

 little duller and darker, probably from a slight decomposition 

 upon the surface. The crystals exhibit a fine dichroism by re- 

 flection, the ordinary image being pale reddish orange, while the 

 extraordinary image is bright orange. The ferrocyanid of Xan- 

 thocobalt is almost insoluble in cold, and is immediately decom- 

 posed by hot or even by warm water. The crystals lose water 

 and are partially dissolved in vacuo, or even in pleno over sul- 

 phuric acid. They can, therefore, only be dried by pressure 

 between folds of bibulous paper. The impossibility oi purify- 

 ing this salt by recrystallization, and the facility with which it is 

 decomposed, render it difficult to obtain it in a perfectly pure 

 state. 



The formula of the ferrocyanid appears to be 



NOa .5NH3.C02O, Cy2+FeCy+7HO, 

 as the following analyses show : 



0-62S8 grs. gave 0-155Y grs. metallic cobalt and iron = 24-'76 per cent. 



O'904Y grs. gave 2239 grs. « « « = 24-14 " 



5896 grs. gave 0-0690 grs. sesquioxyd of iron = 8'19 ** iron. 



0-6006 grs. gave 0-1311 grs. Coa03+4CoO =16*39 « cobalt. 



1-0820 grs. gave 0-4163 grs. carbonic acid = 1049 ** carbon. 



1*1645 grs. gave 0'6439 grs. -water =6-14 " hydrogen. 



0-8718 grs. gave 271 c. c. nitrogen at 20°*8 C. and 765'»''»'04 (at 21^-3 C.) = 246-61 



c. c. at 0° and 760«'» = 35-51 per cent. 

 0-9471 grs. gave 292 c. c. nitrogen at l7°-7 C. and 763''*'»*01 (at IS^ 0. = 26896 



c. c. at 0^ and 760^'*'^^ = 35*66 per cent. 



The formula requires 





Eqs. 



r 



2 



1 



6 



22 



9 



Calculated. 



1. 



16-39 

 8-19 



10-49 

 614 



35-66 



Found. 

 2. 



I 24-76 



1 



V 



35-51 





Cobalt, 



Iron, 



Carbon, 



Hydrogen, 



Nitrogen, 



10-25 

 6*26 



35-89 



3 



24-' 



These analyses agree with the formula as well as can be reason- 

 ably expected, when the difficulty of obtaining a perfectly pure 

 salt is taken into consideration. It is interesting to remark that 

 in this salt,, in which there is but one equivalent of basic cyanid, 

 there are^ still two equivalents of cyanogen in the basic for one 

 in the acid or electro-negative cyanid. 



XA.NTHOCOB 



w 



of anmionia added, and a current of NOx passed through the 

 liquid, an absorption takes place, and copious fumes of carbon- 



