ACTIVE VOLTAIC ARRANGEMENTS WITHOUT METALLIC CONTACT. 115 
observations and facts to show the number of these cases, and their force. In the 
Eighth Series of these Researches * (April, 1834,) I gave the first experiment, that I 
am aware of, in which chemical action was made to produce an electric current and 
chemical decomposition at a distance, in a simple circuit, without any contact of 
metals (880, &c.). It was further shown, that when a pair of zinc and platinum 
plates were excited at one end by dilute nitro-sulphuric acid (880.), or solution of 
potash (884.), or even in some cases a solution of common salt (885.), decomposi- 
tions might be produced at the other end, of solutions of iodide of potassium (900.) 
protochloride of tin (901.), sulphate of soda, muriatic acid, and nitrate of silver (906.); 
or of the following bodies in a state of fusion ; nitre, chlorides of silver and lead, and 
iodide of lead (902. 906.) ; no metallic contact being allowed in any of the experiments. 
2018. I will proceed to mention new cases; and first, those already referred to, 
where the action of a little dilute acid produced a current passing through the solution 
of the sulphuret of potassium (1831.), or green nitrous acid (1844.), or the solution of 
potassa (1854.) ; for here no metallic contact was allowed, and chemical action was 
the evident and only cause of the currents produced. 
2019. The following is a table of cases of similar excitement and voltaic action, 
produced by chemical action without metallic contact. Each horizontal line con- 
tains the four substances forming the circuit, and they are so arranged as to give the 
direction of the current, which was in all cases from left to right through the bodies 
as they now stand. All the combinations set down were able to effect decomposition, 
and they are but a few of those which occurred in the course of the investigation. 
2020. 
Iron. 
Dilute nitric acid. 
Platinum. 
Sulph. of potassium (1812.). 
Full current. 
Iron. 
Dilute nitric acid. 
Platinum. 
Red nitric acid. 
Full current. 
Iron. 
Dilute nitric acid. 
Platinum. 
Pale nitric acid, strong. 
Good. 
Iron. 
Dilute nitric acid. 
Platinum. 
Green nitrous acid. 
Very powerful. 
Iron. 
Dilute nitric acid. 
Platinum. 
Iodide of potassium. 
Full current. 
Iron. 
Dilute sulphuric acid. 
Platinum. 
Sulphuret of potassium. 
Full. 
Iron. 
Dilute sulphuric acid. 
Platinum. 
Red nitric acid. 
Good. 
Iron. 
Muriatic acid. 
Platinum. 
Green nitrous acid. 
Most powerful. 
Iron. 
Dilute muriatic acid. 
Platinum. 
Red nitric acid. 
Good. 
Iron. 
Dilute muriatic acid. 
Platinum. 
Sulphuret of potassium. 
Good. 
Iron. 
Solution of salt. 
Platinum. 
Green nitrous acid. 
Most powerful. 
Iron. 
Common water. 
Platinum. 
Green nitrous acid. 
Good. 
Zinc. 
Dilute nitric acid. 
Platinum. 
Iodide of potassium. 
Good. 
Zinc. 
Muriatic acid. 
Platinum. 
Iodide of potassium. 
Good. 
Cadmium. 
Dilute nitric acid. 
Platinum. 
Iodide of potassium. 
Good. 
Cadmium. 
Muriatic acid. 
Platinum. 
Iodide of potassium. 
Good. 
Lead. 
Dilute nitric acid. 
Platinum. 
Iodide of potassium. 
Good. 
Lead. 
Muriatic acid. 
Platinum. 
Iodide of potassium. 
Good. 
Copper. 
Dilute nitric acid. 
Platinum. 
Iodide of potassium. 
Copper. 
Muriatic acid. 
Platinum. 
Iodide of potassium. 
Lead. 
Strong sulphuric acid. 
Iron. 
Dilute sulphuric acid. 
Strong. 
Tin. 
Strong sulphuric acid. 
Iron. 
Dilute sulphuric acid. 
Strong. 
Copper. 
Sulphuret of potassium. 
Iron. 
Dilute nitric acid. 
Powerful. 
Copper. 
Sulphuret of potassium. 
Iron. 
Iodide of potassium. 
Copper. 
Strong nitric acid. 
Iron. 
Dilute nitric acid. 
Very powerful. 
Copper. 
Strong nitric acid. 
Iron. 
Iodide of potassium. 
Silver. 
Strong nitric acid. 
Iron. 
Dilute nitric acid. 
Strong. 
Silver. 
Strong nitric acid. 
Iron. 
Iodide of potassium. 
Good. 
Silver. 
Sulphuret of potassium. 
Iron. 
Dilute nitric acid. 
Strong. 
Tin. 
Strong sulphuric acid. 
. 
Copper. 
Dilute sulphuric acid. 
* Philosophical Transactions, 1834, p. 426. 
Q 2 
