356 Experimental Researches in Electricity. 



our approach, and we are encouraged to proceed by dis- 

 cerning occasionally among the comparatively inferior ma- 

 terials that bestrew our paths, the sparkle of the rich ore 

 that ere long will so abundantly reward our efforts. One 

 path more must be traversed before we reach the grand 

 object of Faraday's labours, but happily we shall find much 

 that is novel in it, to excite our curiosity, all that is beauti- 

 ful in inductive research to gratify our reasoning faculties, 

 abundant materials for thought, and to those who love it, 

 for speculation also. 



The fourth series of the experimental researches is oc- 

 cupied with the development of a new law of electric con- 

 duction, and with considerations on conducting power in 

 general. " It was during the progress," says Faraday, " of 

 investigations relating to electro-chemical decomposition 

 which I still have to submit to the Royal Society, that I 

 encountered effects due to a very general law of electric 

 conduction not hitherto recognised : and though they pre- 

 vented me from obtaining the conduction I sought for, they 

 afforded abundant compensation for the momentary disap- 

 pointment, by the new and important interest which they 

 gave to an extensive part of electrical science." 



The first indications of this new law, were obtained by 

 Faraday while working with ice and the solids resulting 

 from the freezing of solutions, and he found that the inter- 

 position of the slightest possible film of such solid matter 

 between the conducting portions of a voltaic arrangement 

 wholly interrupted the power of conduction, however well 

 the same body might conduct in its fluid state. 



By an ingenious arrangement of platinum plates in small 

 tin vessels filled with water, which was subsequently frozen 

 by a mixture of salt and snow, a thin plate of solid ice 

 was made to intervene between the tin and the platinum. 

 By connecting the tin and platinum respectively with the 

 opposite poles of a voltaic battery, a strong current of elec- 



