I
21
KINETIC ENERGY OF ELECTRICITY IN MOTION [1]
the laboratory. In A (the secondary circuit) the galvanometer
and one branch of the spiral C were introduced; in B the
battery, the tangent galvanometer, and the commutator.
The induction of the circuit B on A was first determined.
As this was very small, the above described method of experi-
menting and calculating
was used, in which the
circuit A was as a rule
broken.
of the rectilinear system
B on the spiral C was
not zero, the latter was
inserted in the circuit
in both of the two pos-
sible ways. The values
As the action
of the inductive kick
Sou
1500
A
B
6430
FIG. 4.
were observed for different strengths of the primary current;
after reduction to the same strength (100 scale divisions of
the tangent galvanometer) they were found to be-
1. For the first position of the spiral:
In scale divisions of the galvanometer,
0.3997, 0.3955, 0.3791, 0·4006.
2. For the second position:
=
Mean 0.3939;
0.3034, 0.3102. Mean =0·3068.
The mean of the two values, namely 0-3502, gives the induc-
tion of the circuit B on A. The corresponding logarithmic
decrement was that of the needle swinging freely, namely
λ = 0·0172.
In order to compare the kick with experiments made with a
different damping we must multiply it by
π
tan-17,
еп
T
which gives the value
1.1097
T
The remaining detached branch of the spiral C was now