PROFESSOR DANIELL ON THE ELECTROLYSIS OF SECONDARY COMPOUNDS. 217 
tained that, in aqueous solutions of the fixed alkalies, the oxides travel in the contrary 
direction to that of the acid in the dilute sulphuric acid, and that the amount thus 
transferred to the platinode was certainly below that of the equivalent of the gases 
evolved. I lost no time in endeavouring to ascertain the exact proportions ; but met 
with some difficulty from the rapid action of the alkaline solutions upon the mem- 
branes of the connecting tube. This was at last overcome by closing the apertures 
with ground disks of porous earthenware tied down with pieces of calico. The mean of 
two experiments, in each of which 35‘4 cubic inches of the mixed gases were collected, 
showed, by saturation with sulphuric acid, five grains of potassa transferred to the pla- 
tinode, or something less than one fifth of an equivalent for an equivalent of the gases. 
Experiment 35. — A solution of baryta of the specific gravity 1008’5 was found to 
conduct very badly, and only 7‘3 cubic inches of mixed gases could be collected in 
five hours. The transfer of baryta to the platinode was ascertained by precipitation 
with sulphuric acid to be T53 grs., whence we may calculate that the transfer for 
one equivalent of the gases would be 14‘84, or about one fifth equivalent : for 
Mixed gases. Mixed gases. Baryta. Baryta. 
7-3 : 70-8 :: ] *53 : 14'84 = f nearly. 
Experiment 36. — A solution of strontia of the specific gravity 1007 proved to be a 
worse conductor even than the preceding: but the experiment was allowed to pro- 
ceed for twenty-one hours, when 327 cubic inches of mixed gases were found to have 
been collected. The platinum platinode was covered with crystals of hydrate of 
strontia. The liquid in the zincode cell was scarcely rendered turbid by sulphuric 
acid, while the solution in the platinode cell afforded 14 grs. of sulphate of strontia, 
so that the whole of the strontia, or 7‘9 grs., had passed over to the platinode. 
Scarcely a globule of gas was evolved from the electrodes at the time when the expe- 
riment was stopped, although the battery was still capable of evolving gas in the vol- 
tameter at the rate of about one cubic inch per minute. 
Now, if we suppose that no gas was evolved after the whole of the strontia had 
passed over, the transfer was in the proportion of about one third equivalent for an 
equivalent of the gases, for 
Mixed gases. Mixed gases. Strontia. Strontia. 
327 : 70-8 :: 7'9 : 171 = ~ nearly, 
but as it is probable that there was some excess of gas from the long continuance of 
the experiment, the result cannot be held to differ materially from the preceding. 
Experiment 37- — I now took a solution of baryta of the specific gravity 1033 and 
ascertained, by precipitation with sulphuric acid, that a measure of it contained 26'9 
grs. of baryta. I charged the cell with an equal measure of the same solution, and 
placed it in the voltaic circuit with a voltameter, with the intention of carrying on 
the experiment till the whole of the baryta had been transferred, as was the case with 
the strontia of the last experiment. The results were not examined till the expira- 
tion of forty-eight hours. The quantity of gases collected amounted to 139 cubic 
mdcccxl. 2 F 
