180 



THE ELECTRICAL RESISTANCE AND 



very considerable at times with the method of experimenting, 

 their results do not appear to be very reliable. 



The method just outlined was first used and investigated, 

 with results similar to those obtained by Ayrton and Perry 1 

 and to those obtained by Dr. Bronson. 2 



A D'Arsonval galvanometer, manufactured by Leeds and 

 Northrup, was used as a current measurer, its sensitivity and 

 resistance being first determined. 



The resistance was determined by several methods, the 

 mean of these several 

 values being taken and 

 found equal to 1930 

 ohms, at 17 C. 



The sensitivity, or 

 current which produces 

 a deflection of one scale 

 division was determined 

 as follows: 



The galvanometer 

 was connected in a cir- 

 cuit as shown in Fig. 4. 



FIG. 4. 



E is a 10,000 ohm resistance coil, 

 C is a standard one, (1), ohm coil, 

 A is a storage cell, 

 B is a 1000 ohm coil. 



The E. M. F. of the storage cell, as determined by a Weston 

 voltmeter was 2.00 volts, so the current passing through the 



2 



ohrrrS 



galvanameter, i = 



1000 



10000 + 1930 



amperes. 



1. Loc. cit. 



2. Loo. oil. 



