ELECTEIC DISCHAEGE WITH THE CHLOEIDE OF SILVEE BATTEET. 113 
removed 514 grms. oxychloride of zinc ten months after charging ; from battery 5, of 
1200 cells, 894 grms. ; and battery 4, 1200 cells, 809 grms., sixteen months after 
charging. This deposit is in hexagonal plates, and on analysis was found to have the 
following composition : — 15 ZnO, 3 ZnCl 2 -f- 20 H 2 0. 
Theory. 
Found. 
18 Zn 
1173-6 
59-07 
58-33 
58-33 
15 O 
240-0 
12-08 
6 Cl 
213-0 
10-72 
11-82 
11-82 
11-40 
20 H 2 0 
360-0 
18-13 
17-40 
16-20 
1986-6 100-00 
The formation of oxychloride of zinc is not peculiar to the chloride of silver battery, 
but takes place in all batteries where the zinc is immersed in a solution of a neutral 
chlorine compound (zinc chloride, sodium chloride, ammonium chloride). 
We found the vulcanised stoppers to be a source of great trouble ; in the first 
place, their elasticity frequently causes the tube to split, not at first possibly, but after 
the lapse sometimes of many months. Moreover, after a year or so, many of them 
become in some measure conducting, and slowly run down the cell, and we have had 
many cases where a current of high potential has run along the top, and set fire to the 
stopper. W e have, therefore, entirely discarded vulcanised stoppers, substituting paraffin 
in our recent batteries and replacing broken down cells with vulcanised stoppers by 
others with paraffin. The paraffin stoppers may be cast solid, as they are easily bored 
in a lathe with the American drill ; generally about five sizes are requisite to suit the 
various dimensions of the tubes used for cells, for it is quite impossible to obtain them 
of uniform diameter. 
After having been in almost daily use during ten months, it was found that, in 
batteries 6 and 7, 3 "57 grms. of the chloride of silver rod, weighing originally 13 
grms., had been reduced, and 4 "57 in batteries 4 and 5, which had been in use 
sixteen months ; so that, when once set up, the life of the battery is sufficiently long, 
say three years, to admit of a great variety of experiments being made with it before 
it becomes necessary to renew it. The loss of silver is not great, and on this point we 
are able, in consequence of an accidental circumstance, to give precise information ; 
600 powder cells which had been charged up each with 14"5 grms. chloride of silver, 
ran down in consequence of portions of the zinc rod falling down on to the chloride 
equivalent to 0'3689 grm. acid. It is better to dilute the acid with an equal volume of distilled water 
before introducing it into the cells, which is conveniently done by means of a graduated pipette 
furnished with a stop cock. An effervescence takes place, and it is therefore necessary to allow tho 
tubes to remain twenty-four hours without the small paraffin plug being replaced, in order to permit 
the hydrogen, which is generated, to escape ; the acid dissolves 0'3295 grm. of zinc, or its equivalent of 
oxide. It required two days for each battery, 1200 cells, to perform this operation. — Nov. 29, 1877. 
MDCCCLX XVIII. Q 
