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VIII. On the Insulation of Fluorine. By George James Knox, Esq., A.M., 

 M.R.I.A., and the Rev. Thomas Knox, M.R.I.A. 



Read lOtli April, 1837. 



1 HE composition of hydro-fluoric acid had been a subject of discussion among 

 chemists until the year 1810, when M. Ampere, from considering the analogy 

 which subsisted between this acid and muriatic, was led to draw similar conclu- 

 sions with respect to the composition of each. Sir Humphry Davy was at first 

 opposed to these views, but on further consideration, being led to change his 

 opinion, he brought forward experimental proofs of their correctness, which may 

 be found In the Philosophical Transactions.* 



Having by these experiments demonstrated the probable existence of fluorine, 

 he proceeded to other experiments with the view of obtaining it in an insulated 

 state ; for which purpose he heated fluoride of mercury and fluoride of silver in 

 glass vessels, filled with chlorine ; he obtained chloride of silver from the one, 

 and corrosive sublimate from the other ; and the vessels were found to be filled 

 with fluosilicic acid and oxygen arising from the decomposition of the silica by 

 the nascent fluorine. He obtained similar results when fluoride of potassium and 

 fluoride of sodium were heated with chlorine. 



When the same experiments were repeated in vessels of platinum and silver, 

 the vessels were powerfully acted upon. In glass vessels, coated with cuprane and 

 horn-silver, the chlorides were fused at the temperature required for the expe- 

 riments, and the glass was acted on as before. In a platinum vessel coated with 

 fluoride of potassium, a gas was obtained having an odour more disagreeable than 

 that of chlorine ; but the platinum was found to have been acted upon. Sir 

 H. Davy made many other experiments with the view of decomposing hydro- 

 fluoric acid by means of chlorine and oxygen, by passing these gases with the 



* Phil. Trans. 1813, p. 263. 

 VOL. XVIII. T 



