i>kCOMP08ITiON o£ FLUORIC ACIlJ. $$ 



fibon found, that it held in solution a pretty large quantity 



of boraeic acid. 



The fluoric acid arising from the decomposition of fluate Fluate ofliin* 

 i» ,• i • *i i • , ±. i , and acid phos- 



of lime by boraeic acid not being pure, we attempted to phateoflime 



prepare it by decomposing this salt by the acid phosphate yielded a fluo- 

 of lime. We obtained but very little; and what we did with siiex in U. 

 obtain contained in the first place the 6mall quantity of 

 silex, that existed in our fluate of lime, and secondly a cer- 

 tain portion of the acid phosphate of lime itself. What is 

 remarkable in this process is, that, when we used a siliceous 

 fluate of lime, the decomposition of the salt was very rapid$ 

 in consequence of the action of the silex on fluoric acid, 

 and gave rise to a great deal of siliceous fluoric gas. 



Considering then, that the fluoric gas arising from the Fluate of llm« 



fluate of lime and boraeic acid contained no water, and <j ec0Tn P°sed 

 ,,„,.,. , , by sulphuric 



was not capable of dissolving any, we thought, contrary to acid in leaden 



the generally received opinion, that the case would proba- vesse * 8 



bly be the same with that prepared in leaden vessels by 



means of concentrated sulphuric acid* 



But instead of obtaining the acid in the state of gas by yielded only a 

 this means, we had it in a liquid state, and possessing the Iiquid acld# 

 following properties. In the air it emits dense vapours : i» s properties* 

 with water it heats and even enters suddenly into ebullition : 

 it scarcely comes into contact with glass before it destroys 

 its polish, heats strongly, boils, and is converted into sili- 

 ceous gas. Of all its properties the most extraordinary is 

 its action on the skin. It scarcely touches this when it dis- Singular actios 

 organizes it. A white spot is immediately seen, a great OIi l ^ e s ^ in * 

 pain is soon felt : the parts adjacent to the point touched 

 speedily grow white and painful ; and in a little time a. 

 blister is formed, covered by a thick white skin, and con* 

 taining matter. 



However small the quantity the phenomena equally take 

 place; only they proceed more slowly, so that sometimes 

 they are not observed till seven or eight hours after the con- 

 tact ; and still the burn will be sufficiently severe, to causa 

 acute pain, deprive the patient ©f sleep, and excite fever. 

 The effects of these burns, as we are convinced by our own 

 experience, may be stopped by the immediate application of », , 

 a. weak solution of caustic potash ; which we know too, by against burns. 

 Vol. XXIV.—Sept, 1809. © expe- 



