ELECTRIC DISCHARGE WITH THE CHLORIDE OF SILVER BATTERY. 
501 
being of aluminium. Nos. 1, 2, and 3 are idle probing wires of platinum, covered 
with miniature glass tubes, except their extreme ends. The end of No. 1 is about 
0'02, No. 2 0‘2, and No. 3 0 - 6 inch from the ring. 
In the following experiments variations were made : in one case the battery was 
insulated and its pole A connected with the point, and its pole Z with the ring; either 
a stout or a fine wire was then led from the ring, negative, to earth. At other times 
the battery was uninsulated, the pole A being connected to the point, and the pole Z 
with earth, and a stout or a fine wire led from the earth connexion to the ring. The 
stout wire, 0*06 inch diameter, was that ordinarily used in connecting the battery, the 
fine wire, 3 feet of platinum, 0*002 inch diameter, and having a resistance of 81 ohms 
at 19°*2 C. 
Fig. *24, I. and II., shows the different arrangements. 
Fig-. 24. 
In I. the battery is insulated, the silver end A being connected with the point, and 
the zinc Z with the ring; from the negative ring a stout wire is led to the lower 
portion of the key K, and the earth connexion is made with stout wore to the upper 
part of the key, so that in the position shown in the figure the communication to 
earth is through the line wire, but when K is pressed down then the earth communi¬ 
cation is through the stout wire. 
II. shows the battery uninsulated, the silver end A being connected to the point, 
and the zinc Z to the upper paid of the key. The ring is connected to earth by a 
stout wire, and also to the lower part of the key. In the position shown in the figure 
the discharge has to pass through the fine wire to earth, but when the key is pressed 
down it passes through the stout wire. 
MDCCCLXXX1TI. 3 T 
