142 Faraday's Researches

.mode of decomposition are applicable here as were made in
relation to the chlorides when in solution (501).

505. Hydro-fluoric acid and fluorides.—Solution of hydro-
fluoric acid did not appear to be decomposed under the influence
of the electric current: it was the water which gave way ap-
parently. The fused fluorides were electrolysed (153); but
having during these actions obtained -fluorine in the separate
state, I think it better to refer to a future series of these Re-
searches, in which I purpose giving a fuller account of the
results than would be consistent with propriety here.1

506. Hydro-cyanic acid in solution conducts very badly.
The definite proportion of hydrogen (equal to that from water)
was set free at the cathode, whilst at the anode a small quantity
of oxygen was evolved and apparently a solution of cyanogen
formed. The action altogether corresponded with that on a
dilute muriatic or hydriodic acid. When the hydro-cyanic
•acid was made a better conductor by sulphuric acid, the same
results occurred.

Cyanides.—With a solution of the cyanide of potassium,, the
result was precisely the same as with a chloride or iodide. No
oxygen was evolved at the positive electrode, but a brown
solution formed there. For the reasons given when speaking
of the chlorides (501), and because a fused cyanide of potas-
sium evolves cyanogen at the positive electrode,,2 I incline to
t>elieve that the cyanide in solution is directly decomposed.

507. Ferro-cyante acid and the j:en'o-cyanides, as also sulpho-
•cyanic acid and the sulpho-cyanides, presented results correspond-
ing with those just described (506).

508. Acetic acid.—Glacial acetic acid, when fused (141), is
•not decomposed by, nor does it conduct, electricity. On add-
ing a little water to it, still there were no signs of action; on
.adding more water, it acted slowly and about as pure water
would do. Dilute sulphuric acid was added to it in order to
make it a better conductor; then the definite proportion of
hydrogen was evolved at the cathode, and a mixture of oxygen
in very deficient quantity, with carbonic acid, and a little
<carb0nic oxide, at the anode. Hence it appears that acetic acid

11 have not obtained fluorine: my expectations, amounting to con-
viction, passed away one by one when subjected to rigorous examination;
some very singular results were obtained.—December 1838.

2 It is a very remarkable thing to see carbon and nitrogen in this case
.determined powerfully towards the positive surface of the voltaic battery;
but it is perfectly in harmony with the theory of electro-chemical decom-
position which I have advanced. p. 388).2.|