0>0 INQUIRIES RESPECTING FLUORIC ACID. 



conducting nature and lustre of the matter produced by the 

 action of a small quantity of potassium upon the olive co- 

 loured substance, and from all analogy ; there is strong rea- 

 son to consider the boracic basis as metaUic in its nature, 

 and I venture to propose for it the name of boracium. 



7. Analytical Inquiries respecting Fluoric Acid. 



First experi- I nave already laid before the Society the account of my 

 meats cm fluo- first experiments on the action of potassium on fluoric acid 



ric acid gas. «, 



gas*. 



I stated, that the metal burns when heated in this elastic 

 fluid, and that there is a great absorption of the gas. 



Since the time that this communication was made, I have 

 carried on various processes, with the view of ascertaining 

 accurately the products of combustion, and 1 shall now de- 

 scribe their results. 

 Fluoric acid When fluoric acid gas, that has been procured in contact 

 gas introduced w i tn glass, i s introduced into a plate glass retort, exhausted 

 opoassui , a ( ter b e i g filled with hidrogen gas, and containing potas- 

 sium, white fumes are immediately perceived. The metal 

 loses its splendour, and becomes covered with a grayifh 

 crust, 

 and heated. When the bottom of the retort is gently heated, the 



fumes become more copious ; they continue for some time 

 to be emitted, but at last cease altogether. 

 An addition of If the gas is examined at this time, its volume is found 

 hidrogen to the to be a b tt ] e increased, by the addition of a small quantity 

 *" d! " of hidrogen, 



d li- No new fumes are produced by a second application of a 

 cation of heat, low heat; but when the temperature is raised nearly to the 



and tempera- ' nt f sublimation of potassium, the metal rises through 

 ture raised. * ' » 



the crust, becomes first ot a copper colour and then of a 



bluish black, and soon after inflames and burns with a most 



brilliant red light. 



* Phil. Trans., Part II, 1808, p. 343; [Joujpal vol. XXI, p. 375.] 

 The combustion of potassium in fluoric acid I have «ince seen mention- 

 ed in the number of the Moniteur, already so often quoted, as observ- 

 ed by M. M. Gay Lussac and Thenard ; but no notice is taken of the 

 results. [They are given in our present number, p. 29.] 



After 



