HENDERSON 



TEMPERATURE GRADIENTS 



77 



Temperature Co-efficient 



Assuming K = Ko(l+a^), (3) 



then from the equation Kâ^/âz = Q, 

 we obtain by integration Ko{d-\-}4.ad^) =Qz 



Thus, if assumption (3) is correct, the temperature-distance 

 curves would be parabolic. 



On plotting temperatures as abscissae and distances from the 

 lower plate divided by the corresponding temperatures as ordinates, 

 the points were found to lie approximately on straight lines. From 

 these lines the values of a were obtained, as a= —2/c where c is the 

 intercept on the axis of abscissae. 



The experimental curves were also tested on the assumption that 



Since Kdd/dz = Q, we have 2 œ ^ "'^ 



On plotting 6^*^ against z approximate straight lines were also 

 obtained when a suitable value of n, chosen by trial and error, was 

 used. 



Results at High Temperatures 



The results obtained from the experimental curves are given in 

 the following tables: 



Table I 

 Clear Glass 



