Laws of Irreversible Phenomena. 



393 



and, lastly, the quantity of heat which must be " absorbed " 

 in order to compensate the effects of viscosity will be 



+ a vay a*Aay W 

 +2 vb^ aJva* + a*/ 



+ 2 W + ayAa* "3y/' 



= — jjj" d# cfy dz 2^< 



M^) 



In order, therefore, to comply with the rule respecting 

 S'Q we have to write 



S'Q=-$dxdydz2ini 



j. i/S? a^VaS*? a& \ 



+ 2 V^ + a#Aa* a*/ 



+ 2 la* + aWVa* + aW' 



Kio) 



i 



Let us now verify whether in the present case our general 

 principle applies. From (1) we find 



'W^Jt-pJ+^-g + " V2M+ ^ ]S * !=o; (it) 



{ +[ ]%/ + [ ]* ) 



now 





(12) 



