ON FLUOR MINERAL 



this is followed by fluor acid, which covers the inside of 

 both the vessels, together with the surface of the water 

 in the receiver, with a thick siliceous crust. The acid, 

 thus rectified, does not precipitate the solution of silver, 

 and shows not the least mark of muriatic acid. Were 

 Mr. Boullanger's opinion just, the acid, notwithstanding 

 it has been thus purified, should still precipitate the 

 solution of silver, because he maintains that, if the 

 terrestrial part can but be separated from the acid, we 

 should have nothing left but pure muriatic acid. 1 Now 

 we know that this terrestrial part of fluor acid is a 

 siliceous powder ; if, therefore, Mr. Boullanger is able to 

 compose fluor acid with this powder, or any other siliceous 

 substance and muriatic acid, I shall immediately give my 

 assent to his opinion, but not before. Why does not fluor 

 acid mixed with nitrous acid dissolve gold ? Why is no 

 corrosive sublimate produced when fluor acid is distilled 

 with vitriolated mercury ? Why do we not obtain plumbum 

 cornuum on dropping this acid into a solution of lead 

 made with nitrous acid ? etc. Would not all this happen 

 if muriatic acid was contained in pure fluor acid ? I 

 readily believe that Mr. Boullanger was not able to expel 

 the fluor acid from the spar by the strong concentrated 

 nitrous and muriatic acid. Had he made use of those 

 acids a little less concentrated, or diluted as they com- 

 monly are, he would have surely seen the fluor mineral 

 decomposed, as well as it was in my experiment ; for these 

 acids have not so strong an elective attraction for lime 

 as vitriolic acid has; a small quantity of water is there- 

 fore required, and then the fluor is decomposed by means 

 of a double elective attraction. 



1 Exp. d obs., par M. Boullanger, p. 29. 



