>//' \\-ILLIAM SIEMENS, l-.R.S. 



443 



For the reduction of the '2G equations obtained from these 

 observations, the method of least squares was employed, giving 

 a = 0-0119; 0=0 '00112; y = 0'512. 



The following are the results in substituting for the platinum a 

 wiiv of platinum with 20 per cent, of iridium. 



DIAMETER OK WIRE '78 TO '75 MILLIM. 



TEMPERATURE OF ROOM 59 PAHR. LENGTH OF WIRE 100 CENTIM8. 

 CURRENT INCREASING. 



DIAMETER OF wlRE "73 TO -75 MILLIM. 



TEMPERATURE OF ROOM 59 FAHR. LENGTH OF WIRE 100 CENTIMS. 

 CURRENT DECREASING. 



A second series were taken with the same piece of wire, and the 

 current increased until the wire broke. 



