278 Dr. Faraday's Experimental Researches in Electricity, 



and pure distilled water in the vessel B. By the decomposi- 

 tion at e, it appeared as if water was a better conductor than 

 dilute sulphuric acid for a current of such low intensity as to 

 cause no decomposition. I am inclined, however, to attribute 

 this apparent superiority of water to variations in that peculiar 

 condition of the platina electrodes which is referred to further 

 on in this Series (1040.), and which is assumed, as far as I can 

 judge, to a greater degree in dilute sulphuric acid than in 

 pure water. The power, therefore, of acids, alkalies, salts, 

 and other bodies in solution, to increase conducting power, 

 appears to hold good only in those cases where the electrolyte 

 subject to the current suffers decomposition, and loses all in- 

 fluence when the current transmitted has too low an intensity 

 to effect chemical change. It is probable that the ordinary 

 conducting power of an electrolyte in the solid state (419.) is 

 the same as that which it possesses in the fluid state for cur- 

 rents under the due electrolytic intensity. 



985. Currents of electricity, produced by less than eight 

 or ten series of voltaic elements, can be reduced to that inten- 

 sity at which water can conduct them without suffering de- 

 composition, by causing them to pass through three or four 

 vessels in which water shall be successively interposed between 

 platina surfaces. The principles of interference upon which 

 this effect depends, will be described hereafter (1009. 1018.), 

 but the effect may be useful in obtaining currents of standard 

 intensity, and is probably applicable to batteries of any num- 

 ber of pairs of plates. 



986. As there appears every reason to expect that all elec- 

 trolytes will be found subject to the law which requires an 

 electric current of a certain intensity for their decomposition, 

 but that they will differ from each other in the degree of in- 

 tensity required, it will be desirable hereafter to arrange them 

 in a table, in the order of their electrolytic intensities. In- 

 vestigations on this point must, however, be very much ex- 

 tended, and include many more bodies than have been here 

 merjtioned before such a table can be constructed. It will be 

 especially needful in such experiments, to describe the nature 

 of the electrodes used, or, if possible, to select such as, like 

 platina or plumbago in certain cases, shall have no power of 

 assisting the separation of the ions to be evolved (913.). 



987. Of the two modes in which bodies can transmit the 

 electric forces, namely, that which is so characteristically ex- 

 hibited by the metals, and that in which it is accompanied by 

 decomposition, the first appears common to all bodies, al- 

 though it occurs with almost infinite degrees of difference; 



