19S Account of Experiments 



is not the same with iron. I must confess that when any 

 traces of it remain in the cerium it conmiunicates to it a 

 darker red colour ; but as this mailer, when disengaged 

 from iron, as far as chemical means will allow, assumes 

 still a reddish colour by calcination, and as in this state it 

 furnishes as much oxygenated muriatic acid as before, it is 

 equally impossible to ascribe these phienomena to the iron, 

 which, as is well known, produces no oxygenated muriatic 

 acid. 



Thus as cerium, in which the slightest sign of the pre- 

 sence of iron, or of any other foreign matter, could not be 

 detected by any means whatever, always assumes a red 

 colour by calcination, and then gives oxygenated muriatic 

 acid during its solution, I am forced to consider it as a 

 metallic oxide ralher than an earth, as M. Klaproth has 

 done. Hitherto, indeed, chemists were not acquainted 

 with any earth weighing five times as much as water, which 

 has a colour of its own, which absorbs oxygen, and which, 

 dissolving in common muriatic acid, produces oxygenated 

 muriatic acid. 



I had great hope that the reduction of this matter to the 

 metallic state by the action of a strong heat would confirm 

 the above probabilities, and convert them into certain truths ; 

 but this operation \vas not attended with all the success I 

 expected. 



In the first attempt, in which I had put into a charcoal 

 crucible oxalate of cerium reduced to a paste with oil, the 

 whole was volatilized by the violence and duration of the 

 heat : at the bottom of the crucible I found only a metallic 

 grain scarcely so large as the head of a pin, and which was 

 an alloy of iron and cerium. This experiment, if it fur- 

 nished no metal, proves at least that oxide of cerium is vo- 

 latile ; and I do not know that an earthy substance was ever 

 thus volatilized. 



In the second operation I put into a luted porcelain retort 

 a paste made with tartrite of cerium, a little lamp-black and 

 oil, in order thai I might collect the metal if it should be 

 volatilized as before ; but as the form of my apparatus did 

 not permit me to give as much heat, the matter was not 

 reduced : it remained in its natural stale mixed with the 

 charcoal. 



There were seen, however, on the sides of the retort a 

 great number of small globules which had metallic bril- 

 liancy, and the substance of which had been manifestly 

 volatilized. Son>e of the largest of these globules having^ 

 been detached and broken, exhibited in the inside a white 



colour 



