OF ARTS AND SCIENCES. 



119 



Current in Vebers, before metals were placed in coils . . 24.1G9 

 after „ „ . . 22.848 



Difference 8.321 



5808 



Mechanical equivalent = 455.2 metre grammes. 

 No. of reversals of magnetization per minute . . 



The following table exhibits the work done, expressed in metre 

 grammes, in magnetizing and demagnetizing equal volumes of the 

 metals in one minute : — 



The electrical measurements contained in the above tables consisted 

 in deducing the current in Vebers from the deflections of the mova- 

 ble coil of the electrodynamometer, which was placed in the magnetic 

 meridian. The expression for the current is 



c 



■V 



Gg 



tan d 



Where F is directive force of bifilar suspension. 



G and g constants of fixed and movable coils. 



F 

 In the instrument used, the value of — was 10.4 



The resistance of the circuit was measured as accurately as possible. 

 The variations in the current were undoubtedly due to the heating of 

 the machine itself. It was to be regretted that we were not enabled 

 to measure the resistance of the circuit more accurately. This was 

 impossible, under the conditions of the experiments. The mechanical 

 equivalent of the current consumed in heating the metals was deduced 

 from the expression 



W— work = C 2 fit. 



The current 1 Veber in a conductor of resistance one ohm = 



711771 lllQTt 



1.000000 X 10 6 -r - • Which reduced to the unit of work is equal 



sec 2 



1.000000 X 106 



to 



9800 X 10« 



= 102. metre grammes. 



