Royal Institution, 1 3 9 



battery into two kinds — into decompositions by ignition, 

 and polar decompositions. The former are exhibited when 

 compound gases, fluids, or solids are submitted to the 

 airency ot the tire excited by electricity. The latter, when 

 alkaline, earthv, or metallic combinations in a fluid sta;e, 

 or moistened with water, arc acted on by the battery. Mr. 

 Davy illustrated these different decompositions by appro- 

 priate experiments. Sulphurated hydrogen andolefiant gas 

 were decomposed in glass globes by the contact of char- 

 coal. These exj/eriments were novel and impressive, — es- 

 pecially that on sulphurated hydrogen gas, the sulphur was 

 precipitated in the form of a dense white cloud. 



Mr. Daw decomposed soluble and insoluble compounds, 

 as nitre, sulphate of baryies, &c. and in all decompositions 

 he found that alkalies,' metals, metallic oxides, and hy- 

 drogen, were uniformly attracted by the negative surface, 

 and repelled by the positive surface ; and that acids, oxy- 

 gen, and chlorine were uniformly attracted by the positive 

 and repelled by the negative surface. It vias in conse- 

 quence of the discovery of this law of decomposition, that 

 Mr. Daw decompounded the fixed alkalies, the earths, &;c. 

 Mr. Davy explained the transfer or passage of an acid 

 through intervening alkali, or vice versa. In such cases the 

 usual operation of chemical affniity appears to be suspended 

 or destroyed by the agencies of Voltaic electricity. Mr. 

 Davy pointed out the application of the chemical polar 

 agencies of electricity, to obtain alkali from the decompo- 

 sition of neutral salts. 



In illustrating the fusing powers of the battery, the Pro- 

 fessor stated, that the German philosophers were said to have 

 converted charcoal into a sub:>tance analogous to diamond, 

 by a powerful combination. The only eflect which he had 

 been able to witness in trials of this kind, was, that the 

 charcoal became harder at the points of contact. He ex- 

 hibited an experiment in which very fine points of charcoal 

 were electrized in chlorine gas, but there appeared to be no 

 indications of fusion. 



Electrical decompositions and combinations, there is 

 great reason to believe, are constantly taking place in the 

 bosom of the earth and on its surface ; and many of those 

 phsenomcna, says Mr. Davy, which are attril)uted by con- 

 lending theorists, cither to the effects of water or fire, may 

 possibly be owing to more refined agencies operating in the 

 course of ages, aiul pioducing effects scarcely perceptible in 

 ihe short period allotted to human ol)servati()n. 



The surface of the globe must be infiuenoed by the elec* 

 trical changes which occur in the atmosphere, and they 



may 



