in different chemical Processes on Fluor Spar, 271 



able difficulties occurred in executing the process. The 

 liquid fluoric acid immediately destroys glass, and all animal 

 and vegetable substances ; it acts on all bodies containing 

 metallic oxides ; and I know of no substances which are not 

 rapidly dissolved or decomposed by it, except metals, char- 

 coal, phosphorus, sulphur, and certain combinations of chlo- 

 rine. 



I attempted to make tubes of sulphur, of muriates of lead 

 and of copper containing metallic wires, by which it might be 

 electrized, but without success. I succeeded, however, in boring 

 a piece of horn silver in such a manner, that I was able to 

 cement a platina wire into it, by means of a spirit lamp, and 

 by inverting this in a tray of platina filled with liquid fluoric 

 acid, I contrived to submit the fluid to the agency of electri- 

 city in such a manner, that in successive experiments it was 

 possible to collect any elastic fluid that might be produced. 

 Operating in this way, with a very weak Voltaic power, and 

 keeping the apparatus cool by a freezing mixture, I ascertained 

 that the platina wire at the positive pole rapidly corroded, and 

 became covered with a chocolate powder ; gaseous matter 

 separated at the negative pole, which I could never obtain in 

 sufficient quantities to analyze with accuracy ; but it inflamed 

 like hydrogen. No other inflammable matter was produced 

 when the acid was pure. 



In a case in which the acid had been condensed in a tube 

 of lead, joined by a solder containing tin, a large quantity of 

 powder separated at the negative surface of a dark colour, and 

 which appeared to be tin mixed with a subfluate ; the powder 

 burnt when heated in the air, and gave fluoric fumes when 

 treated by potassa and sulphuric acid. 



