10 ESSAY I. 



water ; but as there is siliceous earth likewise produced 

 when no vitriolic acid has been employed, it is evident that 

 this earth has not been separated from the acid of vitriol 

 during the distillation. 



SECTION XVI. 



I dissolved some spar in the nitrous and in the muriatic 

 acid, in a sand bath. From these solutions, a calcareous 

 earth, capable of effervescing with acids, was precipitated by 

 aerated or common fixed alkali. But if the precipitation 

 was performed with caustic fixed, or with volatile alkali, the 

 precipitate was fluor in fine powder. The same thing 

 happened with aerated volatile alkali. When vitriolic acid 

 was added to the above solutions, a precipitation took place 

 immediately, and the precipitate was vitriolated lime. The 

 same thing happens if vitriolated magnesia (Epsom salt), 

 vitriolated vegetable alkali (vitriolated tartar), or vitriolated 

 volatile alkali (Glauber's sal ammoniac), were mixed with 

 the above solutions. 



SECTION XVII. 



I digested powdered fluor with phosphoric acid, which 

 dissolved a good deal of it. On distilling this solution, the 

 fluor acid went over, together with the watery particles of 

 the mixture ; but the remaining mass in the retort had the 

 properties of ashes of bones. 



It has been lately discovered that the earth of bones 

 or horns is calcareous earth combined with phosphoric 

 acid. 



Distilled vinegar and acid of tartar had no effect in 

 decomposing the fluor. 



