ELECTRO-CHEMISTRY. 1 5 



view to withdraw positive electricity absolutely from 

 the acid, and negative electricity from the potassium, 

 I coupled the tube containing the acid which had 

 been used in the decomposition of the iodide, with a 

 tube containing a fresh supply of potassium, and 

 connected their platina wires with each other as is 

 represented in Fig. 1, and inferred that the negative 

 electricity, in combination with the potassium, would 

 withdraw, when the tray was brought to a red heat, 

 what remained, if any, of the positive electricity of 

 the acid; and in like manner I coupled the tube 

 containing the potassium, which had also been used 

 in the decomposition of the iodide, with a tube con- 

 taining a fresh supply of acid, and inferred that what 

 remained of the negative electricity, in combination 

 with the potassium, would be withdrawn by the 

 positive electricity of the acid. 



16. The views that I have advanced at the com- 

 mencement of this Tract on Electro-Chemistry, and 

 the experimental results which I have obtained in 

 corroboration of those views, render the following 

 experiments by Sir H. Davy on the " Transfer of 

 Elements," intelligible. 



17. When three cups, N, I, P, are arranged as 

 represented in the woodcut, and the negative wire 

 from a powerful battery is introduced into cup N, 



