305 



oxide of antimony, with an anode of pure antimony, exhibited no 

 material difference in properties from the less pure variety. 



Two analyses of the pure unchanged substance gave the following 

 per-centages : 



No. 1. 

 Sb . . 93-36 



No. 2. 

 Sb . 93-51 



SbCl 3 5-981 SbCl 



HC1 



99-80 



HOI. 



99-75 



A trace of water contained in them was not estimated. 



Solvents removed the chloride of antimony from the powdered sub- 

 stance much more readily after the thermic discharge than before it. 



Differences of physical appearance were detected in the changed 

 and unchanged substance in the state of powder under a microscope ; 

 the surfaces of the latter were smooth and brilliant, whilst those of 

 the former were granular and less bright. No mechanical mixture 

 could be detected in the changed powder. 



From the various experiments detailed in the paper, it appears that 

 the substance in question is a feeble chemical compound of antimony 

 and acid hydrochlorate of terchloride of antimony, apparently in 

 variable proportions, decomposable by heat, and that the change 

 observed in it, in cases of gradual discharge, consists of a molecular 

 alteration, attended by weakened chemical affinity, and by evolution 

 of heat ; but in cases of sudden discharge the evolved heat produces 

 a partial chemical decomposition, which is of greater or less extent, 

 according to the temperature acquired. 



A portion of the powdered unchanged substance, digested sixty- 

 three days with an aqueous solution of caustic potash, lost 2 -95 per 

 cent, in weight, but still retained about fths of its heating power. 

 A second portion, digested fifty-six days with strong hydrochloric 

 acid, lost 6*66 per cent, and all its heating power. 



Exposure to light did not destroy the heating power of the 

 powdered substance. 



By depositing the grey variety of antimony into mercury, a pasty 

 compound of the two metals was formed. The amorphous variety 

 did not combine with mercury under similar circumstances. 



An acid solution of fluoride of antimony yielded by electro-depo- 

 sition grey crystalline antimony not possessing the heating power. 



Y2 



