336 



electrolization of a fluoride, using as the positive electrode 

 some substance with which this energetic principle should 

 not enter into chemical combination. 



" Finding that, since the publication of our paper, no per- 

 son had entered upon this field of investigation, I considered 

 that the ultimate solution of this problem devolved as a 

 point of duty upon myself; under which impression I un- 

 dertook tbe following experiments. 



" A fluorspar stopper was made to fit the mouth of one of 

 the fluorspar vessels described in our former paper ; tbat 

 part of the stopper within the vessel being made of the form 

 of a semi-cone, the vertex of which reached nearly to the 

 bottom of the vessel. Through the stopper were drilled ver- 

 tically three small holes, one through its entire length, the 

 other two through one-third of its length. In the first 

 was inserted a platinum wire, to be used as the negative 

 electrode ; in one of the two small holes was inserted a thin 

 platinum wire, bound round a piece of charcoal, intended to 

 form the positive electrode ; in the other hole I put gold 

 leaf, litmus, or any other substance upon which I wished to 

 try the action of the gas. Matters being so arranged, the 

 fluorspar vessel was about half filled with anhydrous hydro- 

 fluoric acid, the chemical purity of which had been previously 

 ascertained. Tbe platinum wire forming the negative elec- 

 trode was raised a little above the bottom of the stopper, in 

 order to allow the bubbles of hydrogen to rise through the 

 perforation in the stopper, in place of mixing with the fluo- 

 rine in the vessel; the wires were then placed in contact 

 with the poles of a constant battery of sixty pair of plates, 

 and the action was allowed to continue for the space of two 

 hours ; at the end of which time the litmus was found to be 

 reddened, and the gold not acted upon, but a large quantity 

 of subfluoride of iron formed. 



" In the next experiment I made use of a piece of char- 

 coal, from which the iron had been removed by boiling it in 



