1 ELECTRO-CHEMISTRY. 



of the thickness and hardness that I required ; and 

 I now proceed to detail those experiments in which 

 the iodide of potassium, contained in the small bent 

 tube, was decomposed by electricity, of which the 

 positive electricity was derived either from an acid, 

 or from oxygen or iodine, and the negative electricity 

 from a metal or an alkali ; thus proving that positive 

 electricity is in combination with the first class 

 of bodies, or what are called the supporters of com- 

 bustion, and negative electricity with the second 

 class, or what are called combustible bodies. 



Experiments with Tubes of German Glass. 



Exp. 1. October 22, 1857. 



9. Iodide of potassium, decomposed by electricity ; 

 the positive electricity derived from nitric acid, and 

 the negative electricity from sodium. 



Two tubes hermetically sealed were put into the 

 tray (Fig* 2.), both of which were embedded in a 

 mixture of plaster of Paris and finely-sifted coal- 

 ash. One of the tubes contained about two grains 

 of nitric acid, and the other an equivalent quantity 

 of sodium. From the interior of these tubes, platina 

 wires projected beyond the tray, and to prevent the 

 wires from coming in contact with the iron of the 

 tray, they were encased in capillary tubes. These 



