254 Dr. E. J. Mills on certain Cobaltamines. 



to which two volumes of water had been added, and finally pre- 

 cipitated with a cold mixture of three volumes of aqueous hydric 

 ehloride and one-third of a volume of spirit. After washing 

 with a fresh quantity of the precipitating mixture, then with 

 alcohol, and drying in the air, the compound corresponds very 

 closely in composition with its formula, as may be seen from the 

 annexed determinations. 



0-3598 grm. substance lost 0*0237 grm. at 100°, and gave 

 02085 grm. cobaltic sulphate. - 



Found. 5NH 3 .CoCP.H 2 0. 



Water . . 659 6-681 . 



Cobalt . . 22-29 22*26 j P er cent ' 



On boiling a solution of the chloride with a trace of hydric 

 chloride, it immediately underwent its remarkable transformation 

 into the purple isomer. Neither potassic iodide nor potassic 

 chromate produced any precipitate with it ; potassic dichromate 

 yielded a brick-red precipitate. These are the reactions of the 

 pure chloride. 



[" Crystallized Cobaltic Chloride." — I have not been able to find 

 any reliable statement of the composition of hydrous cobaltic chlo- 

 ride crystallized from water. It is so much more convenient, for 

 many preparations, to w T eigh cobalt in this form, that I have 

 determined the cobalt and water in the crystals. The substance 

 was prepared for analysis by igniting the /3-ammoniotrichloride, 

 dissolving the black residue in aqueous hydric chloride contain- 

 ing a little hydric nitrate, repeatedly evaporating first with hy- 

 dric chloride and then with water, and ultimate crystallization 

 from the last-named solvent. After thorough drying by the aid 

 of pulverization and pressure between folds of bibulous paper, 

 the following numbers were obtained : — 



0*3410 grm. substance lost (1) 0*1030 grm. over oil of vitriol, 

 and subsequently (2) 0*0510 grm. at 100°. The residue, evapo- 

 rated with hydric sulphate and ignited, furnished 0*2246 grm. 

 cobaltic sulphate. 



Found. CoCl 2 +6H 2 0. 

 Cobalt . . . 25*33 25*10 



Chlorine 29*71 



Loss(l) . . . 30*20 30-13 4H 2 



Loss (2) . . . 14-96 15 6 2H 2 



100*00 



Commercial " pure chloride of cobalt " has very nearly the same 

 composition.] 



