ON FLUOR ACID 35 



SECTION XII. 



If we add together the three kinds of earth obtained in 

 the above process, viz. 



oz. drins. grs. 



(1) The earth in the neck and arch of the retort .030 



(2) The earth that had formed a crust on the 



water . . . . . . . . 57 



(3) The earth that was precipitated out of the 



fluor acid .... ,020 



It amounts upon the whole to . . .0 5 57 



and therefore only to 47 grs. more than the retort had lost 

 of its weight ; which small excess is to be attributed in part 

 to the acid inhering in it, and partly to some moisture 

 attracted by it. To ascertain this, I made each by itself red 

 hot in a small crucible, after which 



oz. drms. grs. 



(1) Weighed 2 36 



(2) . . 21 



(3) . . . . . . . . .0 1 55 



In all 4 52 



which is less by 18 grs. than the loss of the substance of the 

 retort (Sec. ix.) ; they must certainly have escaped in the 

 3 drms. of vapour. 



SECTION XIII. 



Hence, I think, the origin of the earth which makes its 

 appearance during the distillation of fluor, rendered quite 

 evident. It proceeds neither from the spar itself, and still 



