202 Thermal Conductivity of Metals. [June 14 r 



The greatest value obtained for copper was 0'9594 C.G.S. units, 

 which was for wire obtained from Messrs. Glover and Sons. The 

 specific (electrical) resistance was found to be 1730. 



It must be noted that these values are the means of the conduc- 

 tivities corresponding to the temperatures at the ends of the wire. 

 When compared with the values obtained by other experimenters, the 

 results of the latter must be taken for the mean of 97 C. and 10 C., 

 that is 53 C. 



For this temperature Angstrom gives 0'9208. 



Several qualities of copper were tested, as well as pure gold, silver, 

 and platinum, kindly lent for the investigation by Messrs. Johnson, 

 Matthey, and Co. 



The values are given below : 



Experiments to find out if there is any relation between the elec- 

 trical and thermal conductivities confirmed what has been found by 

 previous investigators, that if one metal is a better conductor for 

 heat it is also a better conductor for electricity. The results did not, 

 however, prove that the ratios were always the same, although in some 

 cases they agreed very closely. 



For example 



Conductivity of Specimen 2 in above table ,. T 



^ . J =-. r- =2'78 for heat. 



Conductivity of Specimen 5 in above table 



= 2'86 for electricity. 



Conductivity of Specimen ^ _ 0.54 f v, f 

 Conductivity of Specimen 4 



= 2'56 for electricity. 



Conductivity of Specimen 1 , A0 -, 



* - = r08 for heat. 



Conductivity or Specimen 2 



= T066 for electricity. 



