PRACTICAL STANDARDS FOR ELECTRICAL MEASUREMENTS. 



15: 



1898, -were made, and in addition -we have one result from the tests on 

 coil No. 3873. Altogether we have the following : — 



From readings a, c, e and g, and Mr. Glazebrook's determination of 

 the resistance in December, 1897, which gave Ris90=9'989G ohms, we get 



R,=9-9313 (1 + 0-000481<-0-000004(2)«2). 



Check tests were made on this coil after those on coil No. 3873 had 

 been made, and gave the following results : — 



All the nine points lie on a smooth curve (see fig. 6) . These tests 

 make the coil correct at 16-9° C. 



■0Z4 

 Oil 

 ■ozo 



■Ofg 

 ■OIS 



■oit 

 ■ on 

 ■010 

 -00s 

 •00s 

 ■00* 



■002 



o 



~97t 



Fig. 6. 



£xcess res/Stance //? ohms. 



!• A* /6 /7 10 'S Iff 21 22 23- z* 25 



Curve showing change of resistance of 10-ohm standard coil, No. 3874, -mth change 

 of temperature. Ordinates give excess of resistance of 3874 above 3873 at 17-25° C. 



For purposes of comparison we have a similar set of data to those used 



