Heat-loss by Conduction in Explosions of Coal-gas. 319 



sq. cm. of surface is equal to the amount of heat in the grid 

 per sq. cm. at that instant plus the amount which has passed 

 from the grid into the linoleum backing. The amount of 



Fig. 1. 



heat in the silver grid per sq. cm. at time t is equal to CO, 

 where C is the thermal capacity of the grid per sq. cm. and 

 is the rise of temperature of the grid at that instant. The 

 amount of heat which has passed into the backing at time i 

 may be calculated from the expression 



?{ 



1 • It 2 - 



\ 



where k and c are the thermal conductivity and thermal 

 capacity respectively of the linoleum, the rise of tempera- 

 ture of the surface of the linoleum (which may be assumed 

 to be equal to that of the grid) at time t, and 0, 6 . . . . 

 differential coefficients of with regard to t. 



The thermal conductivity and thermal capacity of the 



