336 On ALLANIfE, fcf<r. 



I omit the 7 grains of junonium, becaufe I only detected it in 

 one fpecimen of allanite. The excefs of weight in the preceding 

 numbers, is to be afcribed chiefly to the carbonic acid combi- 

 ned with the oxide of cerium, from which it was not complete- 

 ly freed by a red heat. I have reafon to believe, too, that the 

 proportion of iron is not quite fo much as 25.5 grains. For, 

 in another analyfis, I obtained only 18 grains, and in a third 

 20 grains. Some of the cerium was perhaps precipitated along 

 with it in the preceding analyfis, and thus its weight was appa- 

 rently increafed. 



