Mr. J. Parker on Thermoelectric Phenomena. 359 



certain temperature T, the current flows through the circuit 

 in the same direction whether the other junction be hotter or 

 colder ; then 



so that the Peltier effect does not then cease, as is commonly 

 supposed. 



Again, by (9), 



dTl t dS n , v 



Hence, by (4), 



If the " specific heats " of electricity in the two metals are 

 proportional to the absolute temperature, so that <r a =l a t, 

 o-p^lpt, we have 



Therefore 



U=\(k a -l a )-(k,-le)\t* + Ct, | 



and 8=i{(k-ZJ-(V-WK + C ' + (y > 



where C, C are independent of t. 

 Now 



Il = (k fi -h)T 2 when*=T; 

 therefore 



C+{(2fc-Z a )-(2^-y}T=0. . . . (12) 



Thus, by (9), the electromotive force of the circuit becomes 



E= { (*«" j) ~ (*'- 1) } ^-^ +°( < - ( o) 

 = -^(t>-t >) + C(t-t )...hy(12) ■ 



= J(^ ){T-^}, (13) 



a formula first obtained by Prof. Tait. 

 Also 



VHKj)-*® 



= l{(^-M-fe-W|-§'...by(ll), 



