6 
PROFESSOR DANIELL AND DR. MILLER ON THE 
We had thus the gratification of establishing by independent testimony the cor- 
rectness of Professor Graham’s theory of the phosphates, and it is with pleasure we 
also observe that his view of the basic character of water in certain saline compounds 
is confirmed by the results of the electrolysis of the three tribasic phosphates ; from 
all of which the same acid was separated, notwithstanding that in two instances water 
obviously constituted one of the three equivalents of base. In our corresponding view, 
one of the three equivalents of metals was represented by hydrogen. 
3. Next in natural order seems to stand the inquiry whether the salts of other 
tribasic acids would afford analogous results to those of the tribasic phosphates. 
(/'.) For this purpose we selected the tribasic arseniate of potassa and water 
(KO, 2HO, As 2 0 5 ) (binarseniate), the platinode cell was charged with a solution of 
the salt, and the zincode cell and connecting cell with solution of potassa. The com- 
bination was found to conduct very well, and oxygen and hydrogen were given 
off at their respective electrodes. The solution in the platinode cell assumed a 
grayish appearance, but there was no smell of arseniuretted hydrogen, nor was any 
arsenic deposited upon the electrode. The solution had become neutral to test paper. 
The liquid in the zincode cell was carefully neutralized by acetic acid, and after- 
wards produced in solution of nitrate of silver, the characteristic brick-red precipi- 
tate of the arseniate of silver (3AgO, As 2 O s ), so that there could be no doubt that 
the tritoxarsenion had travelled into the zincode cell. 
The complicated secondary actions which take place in the electrolysis of organic 
compounds, and which we hope to make the subject of future communications, in- 
duce us to abstain at present from extending this part of our inquiry to the organic 
acids. 
4. An inquiry of considerable interest now claims our attention, viz. the electro- 
lysis of salts whose acids, having the same elementary radicle as some of those which 
have been already examined, are in an inferior degree of oxygenation : such are the 
arsenites and sulphites. 
(g.) A solution of arsenite of potassa (KO, As 2 O a ) was carefully prepared (by dis- 
solving single equivalents of arsenious acid and bicarbonate of potassa in boiling 
water), and placed in the platinode cell of the diaphragm apparatus ; the connecting 
cell and the zincode cell were both charged with solution of potassa. During the 
electrolysis oxygen was given off at the zincode, but an equivalent of hydrogen was 
not obtained at the platinode, the electrode being covered with metallic arsenic, 
which was deposited in such abundance as speedily to render the liquid opake; there 
was no smell of arseniuretted hydrogen. This diffusion of the metal reduced by 
secondary action, throughout the solution, contrasts well with the compact manner 
in which metals are deposited, which, like copper from the neutral sulphate, are 
thrown down by direct voltaic action. The zincode solution was exactly neutralized 
by acetic acid ; after which a yellow precipitate of the arsenite of silver was pro- 
duced on adding nitrate of silver. 
