

E<is. 



Calculated. 



1 



16.39 

 8.19 





Found. 

 2 



Cobalt . 

 Iron 



. 2 

 1 



16.80 > 

 1.91 3 



24.17 



} 



24.16 



Carbon . 



6 



10.25 





10.49 







Hydrogen 



. 22 



6.26 





6.14 







Nitrogen 



. 9 



35.89 





35.66 





35.51 



54 RESEARCHES ON THE 



The formula of the ferrocyanide appears to be 



N0 2 .5NH 3 .CoACy 2 +FeCy+7HO 



as the following analyses show : 



0.6288 grs. gave 0.1551 grs. metallic cobalt and iron = 24.16 per cent. 



0.9041 grs. gave 0.2239 grs. " " " = 24.14 " 



0.5896 grs. gave 0.0690 grs. sesquioxide of iron = 8.19 " iron. 



0.6006 grs. gave 0.1311 grs. Co a 3 +4CoO = 16.39 " cobalt. 



1.0820 grs. gave 0.4163 grs. carbonic acid = 10.49 " carbon. 



1.1645 grs. gave 0.6439 grs. water = 6.14 per cent, hydrogen. 



0.8118 grs. gave 211 c. c. nitrogen at 20°.8 C. and 165 n "".04 (at 21°.3 C.) = 246.51 c. c. at 0° 



and 160°"" = 35.51 per cent. 

 0.9411 grs. gave 292 c. c. nitrogen at 11°.1 C. and 163 mm .01 (at 18° C.) = 268.96 c. c. at 0° 



and 160 mm = 35.66 per cent. 



The formula requires 



24.14 



These analyses agree with the formula as well as can be reasonably 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 cyanide, there are still two equivalents of cyanogen in the basic for one in 

 the acid or electronegative cyanide. 



SULPHATE OF XANTHOCOBALT. 



When pure sulphate of cobalt is dissolved in water, an excess of ammonia 

 added, and a current of NO x passed through the liquid, an absorption takes place, 

 and copious fumes of carbonate of ammonia are given off. The liquid gradually 

 assumes a dark brown-yellow color, and frequently deposits an abundance of crys- 

 tals during the passage of the current of gas. Ammonia must be added from time 

 to time, so as to keep the solution strongly alkaline, and prevent the appearance 

 of red vapors at the surface of the liquid. It is not necessary to apply heat, as 

 the temperature rises from the absorption of the gas. When the operation is over, 

 which is indicated by the color of the liquid, the solution may be filtered and 

 allowed to evaporate spontaneously, when a mass of brown-yellow crystals is 

 obtained. These may be purified by re-solution in hot water with addition of a 

 few drops of acetic acid and re-crystallization. 



This method of preparing the salt is a convenient one, and large quantities may 

 be prepared in a few hours. The time required for the completion of the oxidation 

 depends upon the quantity of sulphate of cobalt employed, and may last from one 

 to twelve hours. It is best to employ a rapid current of the gas. The formation 



