~ 
985 
When now the coils were put immediately near each other, the 
jumps in the galvanometer deflections occurred simultaneously, and 
the galvanometer spots, in the form of a cross, moved as a whole. 
With distances between the coils bigger than 10 em, the average 
deflections of the galvanometer were the same, but the jumps were 
quite incoherent. However, even up to a distance between the coils 
of 7 centimeters, the bigger jumps occurred quite simultaneously, 
which shows, that in the nickelsteel used, crystals exist, or at any 
rate groups of crystals, which have to be considered as a magnetic 
unity, having a length of 7 cm. Possibly these long crystals are 
formed during the drawing process to which the wire is submitted 
while being manufactured. An effort also to submit annealed or 
electrolytic iron to this test did not succeed, as the discontinuities 
in iron are too small to be detected with a moving coil galvano- 
meter (a double-string galvanometer was not at our disposal). 
Appendix. Interpretation of the galvanometer curves. 
If in the galvanometer circuit with a total resistance ran E.M.F. 
dN 
on is induced (by varying the flux MN through the induction solenoid), 
Q 
we have the following ane 
db aN 
Ben LS Aas a mae aE 
we 9 = Ki | 
LT HE aa en | 
where @ is the deflection of the system (moving coil or string), u 
the elastic force or couple, f a friction constant, m the mass or 
16 
moment of inertia of the system, and eae the E. M.F. induced 
( 
dO 
for a change of deflection ee 
Neglecting the selfinductance L, the elimination of 7 yields the 
following equation for the deflection 
d’ do KdN 
ucts On ee See 
moet (f+ ate ae (1) 
K 
The term represents in the usual way the electromagnetic 
damping of the galvanometer. 
If we put (1) in the form 
