108 



CONDUCTION OF HEAT 



By combining these measures with the observations of 

 E. Wiedemann on the change which the specific heat C 

 under constant pressure undergoes with change of tempera- 

 ture, he obtained the law of alteration of the specific heat c 

 at constant volume with the temperature, and gave these 



numbers : 



Values of c. 



Will In er then combined with these the values of the 

 coefficient of viscosity determined by von Obermayer: 



Values of ??. 



From this he was then able to calculate the theoretical 

 value of the conductivity I for both temperatures and com- 

 pare them with the values observed by Winkelmann. 

 Wiillner has arranged his results in a table, which I sub- 

 join, with a slight change, by replacing the value K = 1-53 

 used by Wiillner, and given in the first edition of this 

 book, by the newly-calculated value K = 1-6027, whereby 

 the agreement between theory and experiment has for the 

 most part been somewhat improved. 



Values of f. 



