On the Intensity mict Qmrittty of Electric Omrehts, ' S€IS 

 comprised in the expression 



on taking v successively equal to 5, 4, 3, 2, 0. But D and q 

 are involved symmetrically in equation [e^")- There must 

 accordingly exist a parallel system of conditions derivable from 

 the equation 



|.(^)-o... 



Hence it is manifest that the roots of the final equation in D or 

 q will be expressible by * ' ' 



while '{ 



and that consequently, P, Q, R may all of them be determined 

 by resolving equations of the first, second, and third degrees*. 



Long Stratton, Norfolk, 

 January 14, 1863. 



[To be continued.] 



LIX. On the Intensity and Quantity ef Electric Currents, 



To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 



PERHAPS at the present time a translation of the terms 

 intensity and quantity of electricity into their equivalents 

 in the theory of resistances may not be less acceptable to some 

 of your readers than it has been to me. I shall be glad if the 

 following remarks appear to you of sufficient value for insertion 

 in the Philosophical Magazine. 



I am, your obedient Servant, 



H. Bence Jones. 



Suppose that a hydro-electric and a thermo-electric current 

 produce the same deflection of the same magnetic needle, and 

 that an equal length of wire is then introduced into both circuits. 

 The hydro-electric current and the additional wire may be so 

 selected that no change in the effect of the current on the needle 

 will become apparent, whereas the thermo-electric current will 

 be considerably weakened. 



Again, suppose that instead of the wire, a voltameter is intro- 



ad mad^ it* See this Journal f6r June 1845, vol. xxvi. p. 573. 



2B2 



