OF ARTS AND SCIENCES. 



51 



In the first experiment tlie cold mixture was placed under the re- 

 ceiver of an air pump. The exhaustion was maintained by means of 

 a Richard's air pump. This occasioned a faster evaporation of the 

 ether, and a consequent greater decrease of tehiperature, than could 

 otherwise have been maintained. 



The results obtained are as follows : — 



In the second experiment the temperatures were measured by 

 means of the air thermometer. The bulb of the air thermometer, 

 the junction of copper and nickel, and the bulb of the ether thermome- 

 ter, were placed side by side and surrounded with solid carbonic diox- 

 ide, over which ether was poured. The simultaneous readings of the 

 galvanometer, of the air thermometer, and of the ether thermometer 

 were then taken, after the air thermometer had reached its lowest 

 temperature. 



The followinfi: are the results : — 



In the preceding two experiments the constant of the galvanometer 

 was obtained, as before, by means of the gas battery. 

 In the first experiment, E = 14000 cZ = 47 



30751500 



k=z 



14000 X 47 

 In the second experiment, 72 = 12000 d 



= 46.7 

 48 



•. k = 



30751500 

 12U0U X 48 



= 53.3 



Consequently to obtain the values of the electromotive force for the 

 preceding experiments the values oi d 'X. R must in the first experi- 

 ment be multiplied by 46.7, in the second by 53.3. 



