CH. XXIX. 



THE VOLTAIC PILE. 



263 



FIG. 45. 



a 



This battery is called the ' Crown of Cups,' but though 

 it is so simple, it has not become as famous as the second 

 battery made by Volta, which is still called the ' Voltaic 

 Pile' (see Fig. 45). In this battery the metals are laid one 

 above the other, and have small pieces of card or flannel 

 between them which are wetted with salt and water. The 

 battery ends with a plate of zinc at the bottom, and of 

 copper at the top, and these are connected by the wire, a a. 

 The action passes round this battery just as it did through 

 the cups, and if the wire, a a, is 

 cut in the centre and tipped 

 with charcoal (which, being a 

 fad conductor, causes the elec- 

 tricity to pass with difficulty), 

 a bright stream of fire will be 

 kept up between the points as 

 long as the battery is at work. 

 Such was Volta's discovery, 

 and we owe to it all the power- 

 ful galvanic batteries with 

 which our most valuable ex- 

 periments are now made. He 

 completed his Voltaic pile in 

 1800, just at the close of the 

 century, and even from this slight sketch you may see what 

 grand strides had been made in electricity during the past 

 fifty years. 



Franklin had proved the real action of electricity, had 

 shown it to be the same as lightning, and had brought it 

 down from the sky. Galvani had proved its existence in 

 animals, and led the way to Volta's discoveries ; and Volta 

 had produced it in enormous quantities by two metals and 



The Voltaic Pile (Fownes). 



z, Zinc, c, Copper, a, a, Rod con- 

 necting the top layer of copper with 

 the bottom layer of zinc. 



