MEDICAL BATTERIES. 



49 



(c). The Cruikshank battery was replaced by the cylindrical 

 glass battery (fig. 5), already suggested by Volta, and known as 

 the crown of cups 

 {coiironne de tasses) 

 battery; or by the 

 porcelain trough bat- 

 tery, with movable 

 metallic elements 

 (fig. 6). 



The Royal Insti- 

 tution of London 

 possesses a battery 

 of this construction, 

 containing two thousand pairs of elements. It was with this that 

 Davy and Faraday conducted their admirable experiments. 



{d). Wollaston's battery (fig. 7) differs from the foregoing 

 chiefly in having the surface of the copper double that of the zinc, 

 by which the power is increased. 



Cylindrical Glass Battery. 



*• *■ S S S IS- — Si- — K^ 



Af 



Fig. 6. — Porcelain Trough Battery .= 



Fig. 7. — Wollaston's Battery. 



(e). In the battery of Berzelius (fig. 8), the copper surrounds 

 the zinc, without touching it, and serves to contain the liquid. In 



Fig. 8.— Berzelius's battery. 



' An arrangement intermediate between the trongh battery strictly so called, and 

 the battery of a circle of cups. 



E 



