118 PROCEEDINGS OF THE AMERICAN ACADEMY 



(4) Water. Cobalt. 



Resistance of circuit, 2.64 ohms. 



Current in Vebers, before metal was placed in coil . 

 „ alter „ ,, . 



Difference 



23.97 

 21.715 



Mechanical equivalent = 1363.1 metre grammes. 

 No. of reversals of magnetization per minute . . 



2.255 



5880 



(5) 



Water. 



Nickel. 



Steel. 



Resistance of circuit, 2.64 ohms. 



Current in Vebers, before metals were placed in coils . . 24.355 

 after „ „ . . 20.208 



Difference 4.147 



Mechanical equivalent = 4528.3 metre grammes. 



No. of reversals of magnetization per minute 5784 



Practically, the same result was given when a bar of steel was sub- 

 stituted for the iron. 



(6) 



Water. 



Nickel. 



Resistance of circuit, 2.64 ohms. 



