382 On slLLJNlTE, a new 



was cffe&ed in each by means of heat, though not without con- 

 siderable difficulty. The folutions had an auftere, an d flightly 

 fweetiih tafle. When examined by re-agents, they exhibited 

 the following properties : 



(1.) Pruffiate of potafh. A white precipitate. 

 (2.) Oxalate of ammonia. A wmite precipitate. 

 (3.) Tartrate of potafh. A white precipitate. 

 (4..) Hydrofulphuret of potafh. A white precipitate. 

 (5.) Phofphate of f da. A white precipitate. 

 (6.) Arfeniate of potafh. A white precipitate. 

 (7.) Potafh and its carbonate. A white precipitate. 

 (8.) Carbonate of ammonia. A white precipitate. 

 (9.) Ammonia. A white gelatinous precipitate. 

 (10.) A plate of zinc. No change. 



These properties indicated Oxide of Cerium. I was there- 

 fore difpofed to conlider the fubflance which I had obtained as 

 ">xide of cerium. But on peruhng the accounts of that fub- 

 flance, given by the celebrated chemifls to whofe labours we 

 are indebted for our knowledge of it, there were feveral cir- 

 cumftances of ambiguity which occurred. My powder was 

 dhTolved in acids with much greater difficulty than appeared 

 to be the cafe with oxide of cerium. The colour of my oxide, 

 when obtained from oxalate, by expofing it to a red heat, was 

 much lighter, and more inclined to yellow, than the oxide of 

 cerium. 



In this uncertainty, Dr Wollaston, to whom I communi- 

 cated my difficulties, offered to fend me down a fpecimen of 

 the mineral called cerite, that I might extract from it real oxide 

 of cerium, and compare my oxide with it. This offer I thank- 

 fully 



