INQUIRIES RESPECTING FLUORIC ACID. 23 



in its common form, evolved; but new compounds result, and sulphuric and 

 in one case sulphurets, and sulphites, and in the other phos- 

 phurets, and phosphites of potash, are generated. 



As silex was always obtained during the combustion of the Silexalways 

 chocolate coloured substance obtained by lixiviation, it oc- obtained: pet. 



i.i- • i . t i /» i haps a result 



eurred to me, that this matter might be a result ot the ope- f the opera- 

 ration, and that the chocolate substance might be a com- tion. 

 pound of the siliceous and fluoric basis in a low state ofoxi- 

 genation with potash; and this idea is favoured by some 

 trials that I made to separate silex from the mass, by boiling 

 it in concentrated fluoric acid; the substance did not seem 

 to be much altered by the process, and still gave silex by 

 combustion. 



I endeavoured to decompose fluoric acid gas in a perfectly Fluoric acid 

 dry state, and which contained no siliceous earth ; and lor <Jecomposed by 

 this purpose I made a mixture of one hundred grains of dry ' 



boracic acid, and two hundred grains of fluor spar, and 

 placed them in the bottom of an iron tube, having a stop- 

 cock and a tube of safety attached to it. 



The tube was inserted horizontally in a forge, and twenty an d made to 

 grains of potassium, in a proper iron tray, introduced into act oa potassi« 

 that part of it where the heat was only suffered to rise to o- ene rated. 

 dull redness. The bottom of the tube was heated to white- 

 ness, and the acid acted upon by the heated potassium, as it 

 was generated. After the process was finished, the result in 

 the tray was examined. 



It was in some parts black, and in others of a dark brown. p ro d U ct. 

 It did not effervesce with water: and when lixiviated, af- 

 forded a dark brown combustible mass, which did not con- 

 duct electricity, and which, when burnt in oxigen gas, af- 

 forded boracic and fluoric acid. It dissolved with violent 

 effervescence in nitric acid; but did not inflame spontane- 

 ously in oximuriatic acid gas. 



I have not as yet examined any of the other properties of a compound 

 this substance; but I am inclined to consider it as a com- of tne boracic 

 pound of the olive coloured oxide of boracium, and an oxide ox ides ° TC 

 of the fluoric basis. 



In examining the dry fluoric acid gas, procured in a pro- The dry gas 



cess similar to that which has been just described, it gave ooma,tls Dor a- 



° cic acid, 

 very evident marks of the presence of boracic acid, 



As 



