ELECTRIC DISCHARGE WITH THE CHLORIDE OF SILVER BATTERY. Ill 
G inches (15‘24 centims.) long, and 0’22 inch ^0 '56 centim.) diameter, and perforated at 
the top with a hole O'l inch (0*25 centim.) in diameter, to admit the silver wire of 
the adjoining cell. 
The fluid used for charging the batteries is chloride of ammonium, 23 grms. to 
1 litre of distilled water ; by making use of a glass siphon with a long arm of india- 
rubber tubing, provided with a pinch cock, and terminating in a glass tube drawn 
down to enter freely into the hole in the paraffin stopper, it was found that 2400 cells 
could be charged by one person in ten hours. 
Generally an enormous breakage of tubes takes place, the smaller number while 
inserting the stopper, but far the greater number without any apparent cause, in 
many cases after filling in the fluid, but chiefly before the battery has been charged. 
This is a serious trouble, for as much as 33 per cent, of breakage occurs, and arises 
mainly from the tubes not having been properly annealed. 
The battery behaves, on the whole, extremely well, and all the better the more 
frequently it is used, for idleness is its bane, as it permits of the slow formation and 
close adhesion of a skin of oxychloride of zinc, which interposes an enormous resistance 
in each cell, and reduces the current sensibly when the battery is worked in circuits of 
small resistance ; but for experiments with vacuum tubes, the current is amply 
sufficient, and has, in most cases, to be reduced by external resistance in order to 
protect the terminals of the tubes from fusing. It is remarkably constant, and if 
coupled up through a resistance with a galvanometer in circuit, the deflection of the 
needle has been found to remain constant for several hours ; this we have had frequent 
occasion to do when determining the value of the deflections of our galvanometers in 
absolute units by electrolysis. For example, a battery of 10 elements in series was 
connected through two galvanometers to a decomposition cell containing a solution of 
1 part crystals of silver nitrate and 5 parts of water ; both electrodes were of silver, 
and were weighed before the commencement and at the end of the experiment. The 
current was continued for exactly 1 hour, during which time one galvanometer showed 
a constant deflection of 77°‘7 5, the other with fewer coils 60 o, 75, when it was found 
that — 
The positive electrode had lost 0617 grm., and 
The negative electrode had gained 0‘616 „ 
Mean 0‘6165 ,, 
= 0-0001713 grm. per second. 
3600 8 t 
The resistance of the battery was 55 ohms, that of the decomposition cell was 
3 ohms, and that of two galvanometers together was 5 - 24 ohms, making a total resistance 
of 63-24. 
