.' EXPERIMENTS ON CERITE. 11 [ 



Mr. Vauquelin made feveral unfuccefsful attempts to reduce Reduaion of 

 this metal ; at fir ft he ufed the oxalate made into a pafte with ^ metaI ' 

 fat oil. However, having mixed tartrite of cerium with a very 

 fmall quantity of oil and lamp-black, he put it into a crucible 

 of charcoal bedded in fand in an earthen crucible, and heated 

 it for an hour and half in a forge furnace. A metallic globule 

 fcarcely as large as a pin's head was now left in the coal, but 

 no other trace of cerium could he difcovered, though the fand 

 was examined with the utmoft care. 



None of the fimple acids acted on this globule, but it dif- The globule cx- 

 folved, though with extreme difficulty, in aqua regia, after being 

 triturated. The folution was reddilh, and exhibited unequi- 

 vocal marks of iron : but it likewife gave evident figns of the 

 exiftence of cerium, both by its faccharine tafte, and by the 

 white precipitates which tartrite of potato, and oxalate of am- 

 monia threw down. The metallic globule too was harder, 

 much more fragile, more fcaly in its fraclure, and more white 

 than pure caft iron. 



As from thefe experiments cerium appears to be volatile, a Volatile, but 

 fimilar mixture with the addition of borax was heated in a blinw^it fruit- 

 porcelain retort, to the neck of which a porcelain tube was lefs. 

 adapted. Whether from the infufHciency of the heat however, 

 or from the metal being volatilized without adhering to the 

 neck of the retort, no trace of fublimate was found. But 

 feveral very fmall metallic globules remained in the retort, ad- 

 hering to a black varnifh formed by the borax. There were 

 fame of thefe globules about the upper part of the veflel, to 

 which apparently they had been fublimed by the force of the 

 fire; but all thefe globules together would not have amounted 

 to a fiftieth part of the cerium employed. 



the faits of cerium, decompofed by tartrite of potafh (till contain Simple and read/ 

 traces of iron, the iron remains difiblved in the liquor, particularly method of free-* 

 if a flight excefs of tartrite be employed. Accordingly they have J ng cer ^ ob _ r -\ 

 propoled this method as the beft and fimplf ft for freeing the cerium taining the ox- 

 from iron. The procefs they recommend for obtaining pure oxide "*e P ure « 

 of cerium is, todiflblve in nitro-muriatic acid any quantity of cerite, 

 carefully fele&ed and thoroughly calcined. To filter the folution, 

 neutralize it by cauftic potafh, and then precipitate by tartrite and 

 potafh. The precipitate well wafhed, and afterward calcined, is 

 pure oxide of ceriunu 



Abpaft 



