( 723 ) 



Krom iliis equation can easily be found l>\ a tentative method, 



when k lt L\ and R are given. In the different cases we find (in 

 CGS-units), 



Steel wire k x = 0.166 k t = 0.0015 R = 0.025 



k x = 0.166 k a — 0.0015 R = 0.020 



* 1 = 0.166 /-, = 0.0015 Z2 = 0.015 



German silver wire k x = 070 fc, = 0.0015 R — 0.025 



A-, = 0.070 k, = 0.0015 R = 0.020 - = 0.00149 



R 



C is then found by substitution in (5). These values are given 

 below, together with the values found by experiment, but now 

 expressed in CGS-units. 



Calculated Found 



Steel wire R = 0.025 73 X 10~ 10 29 X 10- |ü 



72 = 0.020 110 X 10- lu 49 X 10~ 10 



72 = 0.015 192 X 10- 10 72 X 10~ 19 



German silver wire R = 0.025 34 X 10~ 10 24 X 10— lo 



72 = 0,020 53 X 10— i» 37 X 10~ ,u 



72 = 0.015 91 X 10~ lu 59 X 10~ 10 



SUver wire 72= 0.025 218 X 10~ 10 46 X 10~ lu 



72 = 0.020 347 X 10-'° QQ X lO" 10 



72 = 0.015 519 X 10- 10 70 X 10-'° 



The agreement must be called bad for the silver wire, satisfactory 

 for the german silver wire. It may be called satisfactory, since 

 different circumstances may be mentioned which make us expect a 

 too small value. Leaving aside the great uncertainty in the values of 

 [\w heal conductivities of metals, to which we cannot here ascribe 

 the bad agreement, since we do not know in which direction this 



