AND STRAIN ON THE ACTION OF PHYSICAL FORCES. 
143 
alteration of resistance would go on increasing as the magnetizing force increased, even 
when there might be no appreciable advance in the value of the magnetism induced. 
A glance at the curves in Table XXVII. will serve to confirm the above view. 
These curves have their abscissae representing both the induced magnetism and the 
alterations of resistance produced by the various magnetizing forces, which latter are 
measured by the ordinates of the curves. The induced magnetism* is represented on 
a scale of 1 mi Him. to one division of the scale of the Thomson’s reflecting galvano¬ 
meter, and the alteration of resistance on a scale of 1 millim. to one division of the 
platino-iridium wire. The ordinates are on a scale of 1 millim. to two divisions of the 
scale of the tangent galvanometer, and each of these latter divisions represents a cur¬ 
rent of ’00023 absolute unit. Each division of the iridio-platinum wire represents 
an alteration of resistance =’000034 per unit; if therefore we take the average of the 
first six values of , namely, ’360, as representing the average alteration of resistance 
effected by a magnetizing current producing a deflection of one division on the scale of 
the tangent galvanometer, we find that the increase of resistance per unit produced in 
, ....... P ’36 x’000034 x 30 
the nickel wire by unit magnetizing force ==-———- —— ( =80/0X10 8 . 
J & fe -00023 x 2100 x’75 x4?r 
Table XXVII.—Curves showing the increase of resistance and the amount of induced 
magnetism produced in nickel wire by different magnetizing forces. 
unanEani BBi ii 
ill 
* There was no appreciable difference between the induced magnetism as determined with the B.C. 
flowing and that without. 
