OF ARTS AND SCIENCES. 35 



HffS, and the chlorine determined in the filtrate after removing the 

 excess of SHj by a solution of ferric alum. 



Antimonio-chloride of Purpureocobalt. — A solution of antimonious 

 chloride added to one of chloride of purpureocobalt gives a precipitate 

 of small, granular, dull violet-red crystals. These may be washed with 

 strong chlorhydric acid and dried by pressure between folds of porous 

 paper, and afterward at 100° C. Water decomposes it readily, with 

 precipitation of SbOCl. The formula of this salt is 



Co,(NH3),oCl, + SbCl3, 



as appears from the following analyses : — 



0-8100 gr. gave 0-3402 gr. SO^Co = 15-99 per cent cobalt. 

 0-6500 gr. gave 0-1370 gr. SbOa = 16-64 per cent antimony. 



The formula requires 16-22 per cent cobalt, and 16-49 per cent 

 antimony. 



Bismuthous chloride gives a lilac red precipitate in solutions of 

 chloride of purpureocobalt, insoluble in strong chlorhydric acid, and 

 readily decomposed by water with precipitation of BiOCl. 



Neutral Chromate. — When a solution of nitrate of purpureocobalt 

 is added to one of neutral potassic chromate, a red crystalline precipi- 

 tate is formed, which, after washing with cold water, may be dissolved 

 in boiling water, with addition of a few drops of acetic acid. After 

 some hours the neutral chromate separates in crystals, which have a 

 peculiar red color with bronze-yellow reflections. The crystals are thin, 

 acicular leaves. . The salt dissolves rather easily in hot water, but the 

 solution is soon more or less decomposed, unless free acid is present. 

 The dilute solution is orange-yellow ; concentrated solutions are red. 

 The dried salt somewhat resembles litharge. Different preparations 

 of this salt gave, on analysis, results which differed somewhat from each 

 other, but only in the amount of water of crystallization. In one 

 preparation 



0-2637 gr. gave 0-2480 gr. CrO^Ba = 43-17 per cent CrO^ 



0-3651 gr. gave 0-0811 gr. cobalt = 22-21 per cent. 



0-3598 gr. gave 0-0058 gr. water up to 170° C. = 1-61 per cent. 



1 consider the loss of weight on heating to arise partly from hygroscopic 

 moisture, and partly from slight decomposition, and believe that the 

 salt is really anhydrous. The formula 



Co,(NH3),,.0.(CrOJ, 



