26 ESSAY II. 



when it was boiled with sulphur, dissolved it. It is probably 

 unnecessary to adduce any more arguments in order to prove 

 that lime is the basis of fluor. After having thus shown that 

 the whole quantity of vitriolic acid employed was retained by 

 the lime, it would appear unnecessary to mention all the 

 experiments which I made, in order to ascertain, whether 

 fluor really contains vitriolic acid. But in order to show 

 the falsehood of Mr. Monnet's assertion on this side also, I 

 shall relate a few of them: (1) Pure acid of fluor does not 

 precipitate the solution of the terra ponderosa. (2) Neither 

 does it precipitate the solution of lead in nitrous acid. (3) 

 Acid of fluor, saturated with alkali of tartar, and evaporated 

 to dryness, then mixed with charcoal -powder, and melted, 

 does not yield hepar sulphuris. Not to mention that 

 several other acids have the power of expelling the acid 

 from fluor. Mr. Monnet, however, might very easily say, in 

 answer to this, that fluor mineral has the property of 

 volatilising all acids, the fixed acids of phosphorus and of 

 arsenic not even excepted. But no good chemist can 

 possibly allow that the crust, sublimed into the neck of 

 the retort and into the receiver, as likewise the selenitic 

 mass remaining in the retort, distilled anew with vitriolic 

 acid, is altogether converted into acid of fluor. 



SECTION VI. 



Mr. Monnet, in order to give further proof that fluor 

 contains no calcareous earth, adduces the following experi- 

 ments : He melts equal quantities of alkali and fluor 

 together, and observes that this mineral is thereby little or 

 not at all changed ; for, after having lixiviated the alkali 

 employed, he dissolved the fluor remaining in the filter in 

 nitrous acid ; and to the solution he added vitriolic acid : 



