Current, and on the Intensities of Voltaic Arrangements. 113 



the passive state of the iron was accompanied by the regular 

 decomposition of water into its gaseous elements. 



It will be remarked also that Schoenbein did not observe 

 the intermitting effects until the intensity of the single cell 

 employed by him was still further diminished by the opening 

 of a new channel for the current by connecting the poles of 

 the cell by a wire of a certain length, whilst I have succeeded 

 in obtaining the alternations of state when using the whole 

 force of five very large cells of Daniell in series. We see 

 therefore that a powerful intensity of current is not always 

 able to retain the positive iron electrode in the passive state. 



On the Intensities of various Voltaic Arrangements. 



We know that the important law which has been established 

 by the labours of Ohm, Fechner and De la Rive, is expressed 



by the formula E = p-, where A is the electro-motive force, 



R the resistance to conduction of the whole circuit, and E is 

 the quantity of electricity circulating in a given time. There- 

 fore, if the resistances of different voltaic circles be made equal 

 to one another, the quantity of current will be proportional to 

 the electro-motive force; and hence we derive the following 

 simple method of determining the intensity of a battery. We 

 take an accurate galvanometer furnished with a coil of great 

 resistance, and connecting the arrangements under examina- 

 tion successively with it, we take the currents indicated by the 

 instrument as the measure of their intensities. I have in this 

 way obtained the following list of voltaic intensities, using a 

 galvanometer which, with the wires attached to it, presented 

 a resistance at least 300 times as great as that of most of the 

 cells under examination. I have made the ordinary cell of 

 Daniell the standard of comparison, calling its intensity 100. 



