PROFESSOR DANIELL ON THE ELECTROLYSIS OF SECONDARY COMPOUNDS. 215 
and for which one equivalent of hydrogen is given off at the platinode, is not more 
than a fourth of an equivalent, nor less than a fifth. The majority of the results, 
however, indicate the former proportion. 
Could it be possible that a whole equivalent of acid was, in fact, carried over to 
the zincode, but was counteracted by that species of endosmose which I have before 
described, by which three fourths of an equivalent might be transported in the oppo- 
site direction to the platinode ? 
As this transfer is, however, more of a mechanical than of an electrolytical nature, 
it could not well take place without a visible rise of the liquid in the platinode cell, 
and none such was ever observed. It occurred to me that this question might be set 
at rest by multiplying the diaphragms between the electrodes. I had already suc- 
ceeded, as I believed, in stopping this action by two diaphragms ; it was impossible 
but that by adding two more some change must be produced in the amount, at least, 
of the endosmose, if any such really took place. 
Experiment 28. — I connected the two electrode cells with a third cell by means of 
a second bent tube with two diaphragms, and all were charged with dilute sulphuric 
acid of the specific gravity 1076. The experiment was continued till seventy-one cubic 
inches of mixed gases had been collected in the voltameter, and lasted five hours. 
The acid in the three cells and two connecting tubes were then separately and care- 
fully neutralized. The acid in the two latter and centre cell had not undergone the 
slightest change in quantity; but in the platinode cell it was deficient, and in the 
zincode cell in excess exactly eight grains. 
Experiment 29. — The experiment was immediately repeated with the same acid, 
and two cells with one connecting tube. The same quantity of gases was collected 
in two hours and forty minutes, and the transfer of acid from the platinode to the 
zincode was found to be exactly the same without any change in the connecting tube. 
No doubt, therefore, can now exist that the transfer of the acid is electrolytic in its 
nature. 
Experiment 30. — I next repeated the experiment with an amalgamated zinc, a 
copper, and a platinum zincode of the same dimensions. The quantity of hydrogen 
gas collected in each case was 23‘7 cubic inches (or half an equivalent). The times 
were respectively forty-six minutes, fifty-four minutes, and fifty-five minutes ; and the 
transfer of acid from the platinode was found to be in each about five grains, or one 
fourth equivalent for an equivalent of the gas. The zinc and copper electrodes had 
lost weight in proportion to the equivalent of the gas. 
These last results are not without interest as regards the electromotive force of the 
battery. The absorption of the oxygen by the copper decreases but little the ob- 
structions of the current, by the removal of an opposing element ; but not only is the 
absorption of the same element effected by the zinc electrode, but an energy of one 
fifth, as measured by the time, added to the current. 
Experiment 31. — The difference of this mere absorption of oxygen by a metal, and 
