418 Dr. Thomas Thomson and Dr. SteeVs [June 



tion mixed with nitric acid, the sulphuric acid was thrown 

 down by means of chloride of barium. The well washed 

 sulphate weighed after ignition 13*36 grs. =4*6 grs. sul- 

 phuric acid. This analysis gives us, 



Peroxide of cerium . . . 6*58 or 7*15 



Sulphuric acid 4*60 ,, 5* 



Water ....... 1*90 



13-08 

 Increase of weight by peroxidizing the cerium 0*33 gr. 



II. 20 grs. of the salt in small silvery needles when ex- 

 posed to a low red heat lost 4*67 grs. The remainder dis- 

 solved completely in water. The solution was mixed with 

 nitric acid, and after a sufficient quantity of muriate of 

 barytes had been added, the whole was boiled in a flask, 

 the sulphate collected, well washed and dried weighed 

 20*05 grs., reduced by ignition to 18*967 grs. =6*54 grs. of 

 sulphuric acid. 



Other 20 grs. of the salt treated in the same way, but 

 substituting muriatic for nitric acid gave 18*86 grs. of 

 sulphate of barytes =6* 51 grs. sulphuric acid; the mean of 

 these two trials gives us 6*52 grs. of sulphuric acid from 

 20 grs. of the salt. 



20 grs. of the same needles gave by oxalate of ammonia 

 19 grs. of hydrous oxalate, leaving after ignition in a close 

 crucible a yellow powder, weighing 9*27 grs. When the 

 ignition was repeated in an open crucible, the weight was 

 not altered, but the colour became red. This analysis 

 gives us 



Peroxide of cerium . . . 9*27 or 7*10 



Sulphuric acid 6*52 ,, 5* 



Water 4*67 „ 3*5 



20-46 

 Here the increase of weight from the peroxidizement of 

 the cerium is 0*46 gr. 



III. 19 grs. of the same crystals lost by gentle ignition 

 4*20 grs. The residuum was introduced into a flask and 

 boiled with a solution of carbonate of ammonia, and filtered 

 while boiling hot. The carbonate of cerium after careful 

 washing weighed when dry 10*7 grs. Being exposed to a 

 strong red heat, it left 8*89 grs. of peroxide of cerium. 



