282 PHENOMENA DEPENDENT ON MOLECULAR PATHS 104 



results on our theory for the quantity of heat which is 

 termed the coefficient of conductivity. 



The coefficient of diffusion D, which was determined in 

 95 by the formula 



D = ^(JVj&A + 

 becomes 



D = 



in our special case in which the two kinds of gas are the 

 same, for we may neglect the small difference in the values 

 of fl and that arise from the inequality of temperature, 

 and therefore by 96 and 97 put 



and by 95 we have also 



N } + N 2 = N. 



The conductivity of a homogeneous gas for heat is there- 

 fore 



1O5. Relation of the Conduction of Heat to 

 the Viscosity 



The formula shows a simple relation of the conductivity 

 to the coefficient of viscosity which by 78 is given by the 

 formula 



v = 0-30967 NmQL. 



From this we find that the conductivity can be expressed in 

 terms of the viscosity and the specific heat of the gas as in 

 the equation 



f = (ITT/ 0-30967) T/C 

 = 1-26812 ye. 



The factor which occurs in this formula is not much 

 greater than 1, and we should not be unjustified if in this 

 theory, which depends only on approximation, we were to 

 put it equal to 1, and thus obtain 



f = r]C. 

 This value would, indeed, have directly resulted if we had 



