326 



THE HUMAN MOTOR 



skin itself may not be very thick. Hence the conducting power 

 diminishes with the lowering of the density of the tissue, e.g. : 



DENSITY c. 



Linen Tricot 0-302 0-0001181 



0420 0-0001523 



The following table compiled by Rubner, is very instructive : 



252. Calorific Loss of Water. To estimate this loss in the case 

 of a bath of water at a temperature t, the procedure is simple and 

 has already been indicated ( 178). According to Boussinesq's (*) 

 theory, verified by various authorities ( 2 ) the loss of heat in a 

 liquid at rest has as its expression : 



Q = A x A ' 233 X K' 533 x C' 467 X (T /) i' 233 , 



in which A is a constant, A the co-efficient of expansion of the 

 liquid, a co-efficient that varies with temperature, K the heat 

 conductivity, and C the specific heat. It is not proposed to apply 

 to man, a formula which especially requires the discussion of each 

 of its terms. 



Aim6 Witz ( 3 ) found that the rate of cooling of a surface in con- 

 tact with water was : 



V = 



x a 1 ' 2 " 3 + 0.000480C 



a being the difference of temperature, S the surface, V the volume 

 of the body and K' a constant. 



(*) Boussinesq (Comptes Rendus Sc. t vols. cxxxii., cxxxviii., cxl.). 

 ( 2 ) L. Ser. Physique 'industrielle, vol. i., p. 160, 1888. 

 ( 8 ) Aim6 Witz, Thtse de Doctoral, Paris, 1878. 



