42 HISTORY OF GALVANISM. 



but he perceived Fourcroy's observation to be 

 correct, that it was necessary to employ large 

 plates to burn the metals. He formed a pile of 

 large plates of zinc and copper, and succeeded in 

 Fuses iron fusing iron wires of considerable thickness ; he at 

 wires. at ia l ast even fused a wire of platina. He found that a 

 battery, consisting of 137-i- square feet of coated 

 glass, was charged by a galvanic apparatus to an 

 intensity equal to itself, in l-20th of a second ; a 

 circumstance which proves the amazing velocity 

 of the fluid. He conceived that the energy of the 

 pile was much augmented when it was kept in 

 an insulated state, and likewise when a solution 

 of the muriate of ammonia was interposed between 

 the copper and zinc plates.* 



Action of We have already noticed the discovery of 

 oxidates Cruickshanks, that the pile acted more powerfully 

 in oxygen gas than in the air of the atmosphere ; 

 and an observation the converse of this, was made 

 by Biot and Cuvier, which confirmed the relation 

 between the action of the apparatus and the che- 

 mical state of the fluid in which it is immersed. 

 When the pile was enclosed in a limited quantity 

 of air, they found that, after some time, the air 

 was sensibly deoxidated.f 



state of The discoveries that were made with the gal- 

 vanic pile, especially by the English chemists, 

 completely established some of the most important 

 points which had previously been subjects of doubt 



* Ann. de Chim. xl. 289. f Ibid, xxxix. 24-2, 



