1501 
2. Let us now suppose that the alternating magnetic force is a 
function of a certain parameter w; then the magnetizations J/,. M,. 
too will depend on w. 
This quantity may e.g. represent the intensity of the current in 
the cireuit which produces the field //, the electromotoric force in 
that circuit or the resistance. The expression of J/ may be written 
in this way 
M=(M,—2M, + M) + UL ZM, Mt 
- + (Mops — 2M ape + Mop) + es, SS BE 
If now we choose rz as the independent Sue and if its varia- 
tions, which we shall suppose to be all equal to each other, be 
denoted by £, a development in a Tarror series gives 
x: 5 v4 4 
ee eM Ee 24 = 
2! dar 4. ans 
For M we now obtain 
92-2 Pd Marti  2°—2 Pt dM, 
gee > dd 
att) dx? 4! 5 dz I f 
If 8 is very small, we may write approximately 
- Mapt — 2Msy , 
and replace further the summation by an integration. 
We may now distinguish different cases: 
a. We may assume the electromotoric force which produces the 
current for the field #7, to be constant and the resistance in the 
circuit to be increased gradually. If the electromotoric force is L, 
’ 
the resistance w, we can represent the field by MZ —= 7.—. In this 
w 
case the resistance w must be substituted for the parameter 2 and 
the increase w of the resistance for the quantity £. This gives 
5 h? R h? we don 
Map =m | 1 —— eS) ee m (1-5 — rd 
Wo 8 aie 
From this follows 
d Mansy 2mh? 
duw 9,4) ER ine soe ij 
while the higher derivatives become zero, so that we obtain 
2mh? mh? wo, a 2mh?w’ “op 
MSS = -.(p — 1)» m ee 
fiet De hdd jf. 
Let us now suppose that Hs, is only very little greater than h, 
<p 
so that we may put Hs, =, then we obtain finally 
84* 
