72 Messrs. J. W. Swan and J. Rhodin. Absolute [May 24, 



the diameter a piece 300 cm. long was taken. The weight was found 



to be 



5'6009 grams. 



The ascertained density of the copper being 8*959 indicates an 

 average diameter of 



(3.) X = 2 



5-6009 



300 x 8-9597T 



= 0-05151 cm. at 15 C. 



This same wii'e was fitted with shunting terminals 250 cm. apart, 

 and wound on one of the previously described reels, and then 

 placed in the circuit. A large number of observations were made at 

 different temperatures : they are arranged in Table II. The following 

 are the headings of the columns : T x = temperature of the unknown 

 resistance ; G x = deflection (proportional to the current) with, the 

 unknown resistance ; G B = deflection when standard ohm in circuit ; 

 T R = temperature of standard ohm ; G x = deflection of unknown 

 resistance (supposing G B to be always 1240) ; G x (6th column) is 

 deflection with unknown resistance (X) in circuit corrected, so as to 

 compare with G B at 1240 and T R at 15 C. ; the figures in this column 

 multiplied by a constant give the resistance of the wire. 



Table II. 



