ELECTRIC DISCHARGE WITH THE CHLORIDE OP SILVER BATTERY. 
63 
revolution of A, B, C, D reverses twice. This piece of apparatus follows the dis- 
charging key, figs. 2 and 3, in order from the poles of the battery, the wire A g being 
in connexion with the bracket B, and the wire Z with B' of the contact key, fig. 2. 
The figure is so distinct as scarcely to require any description ; it will be seen 
Fig. 8. 
Fig. 9. 
that B and D are of one piece of metal, and also A and C of another, the spring 
conductors making contact at 90° distance from each other ; each of the uprights 
supporting the axis of the revolving dise is in metallic connexion with its respective 
insulated clamp. In the position shown in the figure the positive current passes 
from k.g to the upright supporting the axis of the revolving disc and through the 
