54 VOLTAIC BATTERIES. 



poses : added to which it may be remarked, that this form of 

 battery gives rise to no unpleasant or noxious fumes, and this 

 must be allowed to be a great desideratum. 



Grove's Battery. Another form of battery which may be 

 employed is that of which we have already spoken, generally 

 known as Grove's Nitric Acid Battery. It consists of a series 

 of porcelain cells or jars, containing slips of amalgamated zinc, 

 in contact with dilute sulphuric acid, of the same strength as 

 that before recommended for the Smee's arrangement. In these 

 jars are placed parallelepiped vessels, made of porous clay, 

 containing strong nitric acid, into which are immersed slips of 

 platinum foil ; each slip of platinum is attached by a binding 

 screw to the next zinc plate, so as to leave at the one end of the 

 battery a zinc pole, at the other a platina pole. This arrange- 

 ment is by far the most powerful voltaic apparatus yet known. 

 The only disadvantage attending its use is the time required for 

 charging it, which, in a case of emergency, such, for example, 

 as asphyxia from drowning or any other cause, must be of the 

 greatest importance. The annexed figure represents the general 

 appearance of this apparatus. Fig. 11. 



Fig. 11. 



The last form of battery which we deem it necessary to de- 

 scribe, is that invented by the late Professor Daniell, and by him 

 termed the Constant Battery, (Fig. 12) from its power of continuing 



