Heat Vaporization of Water. 91 



Let 



W =Wj + n 9 for the first cylinder 

 W'=u' 1 ^ r u\ for the second cylinder 

 and u^ = m L 

 u\— m'L 

 n 1 _ W — m L 

 ^~ W'-m'L' 



But tfw, = J ^-(T 1 -TJdt 



^2 



where k = specific conductivity 

 A = cross section of con- 

 ductor 

 I = length of conductor 

 T = temperature 

 t = time 

 integrating 



-tf t{T > - V* 



u. 



and 



h A /•' 



u\=^-/"(T,-T,)dt 







<=^p/ (T'.-r,)* 



^jl_ 



"'■ f"{r,-r,)dt 



o 



^2 . 



A 7 A' /•" 



*^ f {Tl -T,)dt 



«'. ~~ /(.-'.A 



