440 ON THE THERMAL CONDUCTIVITIES OF SOLIDS AND LIQUIDS. 



Iff 



4ffL SO" 60 TCP 30 

 G 



Mixture 

 50 per cent, by weight of 



Glycerine and water . . . 

 Acetic acid and water . 

 Ethyl alcohol and water . 

 Glycerine and ethyl alcohol . 



00103 

 00085 

 00080 

 00050 



Mean percentage 



change per degree 



between 25 and 45 C. 



- -0063 



- -0058 



- -0068 



- -0050 



It will be seen from this that the thermal conductivities of mixtures decrease with 

 increase of temperature at roughly the same rate per cent, as their constituents. 



STATEMENT or EESULTS. 



The preceding results may be summarised as follows : 



1. Solids which are not very good conductors of heat, in general decrease in 

 conductivity with increase of temperature in the neighbourhood of 40 C. Glass is 

 an exception to this rule. 



2. Liquids in the neighbourhood of 30 C. follow the same law. 



3. The conductivity of a substance does not invariably change abruptly at the 

 melting point. 



4. The thermal conductivity of a mixture lies between the conductivities of its 

 constituents, and seems connected with the constitution and conductivities by a 

 simple law. 



5. Mixtures of liquids decrease in conductivity with increase of temperature in 

 the neighbourhood of 30 C. at about the same rate as their constituents. 



