1912-13.] Electrical Resistance and Magnetization of Nickel. 209 
contiguous columns of “ calculated % values contain numbers calculated 
according to an empirical formula given below. 
Table B. 
Longitudinal 
Field. 
Resistance Change x 10 4 . 
Transverse 
Field. 
Resistance Change x 10 4 . 
Obs. 
Calc. 
Obs. 
Calc. 
10-6 
+ 11 ±1 
10 
50 
-12 ±5 
-15 
17-7 
+ 24± 1 
23 
110 
-39 ±2 
-45 
28 
+ 38 ± 1 
40 
170 
-65 ±2 
-65 
37 
+ 52 ±4 
51 
270 
-80 ±4 
-79 
+ 50± 1 
130 
-88 ±3 
-87 
47-4 
+ 60± 1 
59 
580 
-90 ±2 
-90 
57 
+ 64± 7 
64 
700 
-91 ±3 
-91 
+ 63 ± 3 
815 
-91-5±1 
-91*5 
In each case the change of resistance increases with the magnetizing 
force, tending to a limit in the higher fields. This is particularly well 
marked in the case of the transverse field, whose values are much greater 
than those of the longitudinal field.* 
The magnitude of the change of resistance is greater for a longitudinal 
field than for a transverse field of the same strength. This, however, may 
be largely a question of relative dimensions. Were the strip as wide as it 
is long, the transverse effect would probably be as large as the longitudinal 
effect under the same field. 
The general march of the change of resistance with magnetizing force 
is shown graphically in the curves marked H and T in the figure on p. 216. 
The values from which these are drawn will be explained later. Inspection 
will show that the numbers of Table B agree very closely with the 
curves. 
It will be seen at a glance that the curves are of the same general type 
as those which show the march of induction with magnetic force. Reason- 
ing from this similarity, I have tried to fit to the curves an empirical 
formula of the type 
R(6 + h 2 ) = ah 2 , 
where R is the increase per 10,000 due to the field h, a and b being constant 
coefficients. The formulae obtained are, for the longitudinal field, h, 
R(789 + h 2 ) = 80h 2 , 
and for the transverse field, t, 
R(12800 + t 2 ) = — 93tf 2 . 
* In a recent measurement with the same strip in much higher fields, the change of 
resistance was found to pass through a maximum in about field 900. 
VOL. XXXIII. 
14 
