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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 the following experiments. 
* A fluorspar stopper was made to fit the mouth of one of 
the fluorspar vessels described in our former paper; that 
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. The 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 
