SILVER, POTASSIUM, ETC. 11 



In 1842 Pelouze* made three estimations by the ignition 

 of the chlorate, with these results : 



60.843 

 60.857 

 60.830 



Mean, 60.843, =t -0053 



Marignac, in 1842,t worked with several different recrys- 

 tallizations of the commercial chlorate. He ignited the 

 salt, with the usual precautions for collecting the material 

 carried off mechanically, and also examined the gas which 

 was evolved. He found that the oxygen from 50 grammes 

 of chlorate contained chlorine enough to form .003 gramme 

 of silver chloride. Here are the percentages found by Ma- 

 rignac : 



In chlorate once crystallized 60.845 



In chlorate once crystallized 60.835 



In chlorate twice crystallized 60.833 



In chlorate twice cr\'stallized 60.844 



In chlorate three times crystallized 60.839 



In chlorate four times crystallized 60.839 



Mean, 60.8392, ±z -0013 



In the same paper Marignac describes a similar series of 

 experiments made upon potassium perchlorate, KCIO4. In 

 three experiments it was found that the salt was not quite 

 free from chlorate, and in three more it contained traces of 

 iron. A single determination upon very pure material gave 

 46.187 per cent, of oxygen and 53.813 of residue. 



In 1845 two series of experiments were published by 



Gerhardt.f The first, made in the usual way, gave these 



results : 



60.871 

 60.881 

 60.875 



Mean. 60.8757, zh .0020 



* Compt. Rend., 15, 959. 



f Ann. d. Chem. u. Pharm., bd. 44, s. 18. 



X Compt. Rend., 21, 1280. 



