I
KINETIC ENERGY OF ELECTRICITY IN MOTION [I]
25
According to theory, the extra current from the spirals
with branches traversed oppositely should have the value
238.67
T
178,978 1.1351
=
37,840,000 T
The value actually observed was 1.1476/T. The differ-
ence between the two amounts to little more than 1/100 of the
total value, while the errors of experiment and of calculation
at most may amount to 1/30. Hence, though the great
agreement between the calculated and observed values is
merely fortuitous, yet the experiment shows that at most
1/20 to 1/30 of the very small extra-current from doubly
wound spirals can owe its existence to a possible mass of the
moving electricity; and the formula given above does in fact
represent the induction of such a spiral to a high degree of
accuracy.
I took it to be unnecessary to make further experiments
with spirals; for even if the observations could be carried to a
higher degree of accuracy, still it was impossible to calculate
exactly the values of the inductances which entered into the
experiments.
FIRST SERIES OF EXPERIMENTS WITH RECTILINEAR WIRES.
With a view to getting conditions of experiment more
favourable in this respect, I attempted to measure the
strength of the extra-current obtained from rectilinear double
wires traversed in opposite directions, and to compare its value
with theory.
For these experiments the bridge was arranged as follows.
Three or four resistances, as before all equal, were made of
thin German-silver wires. Two of these were formed exactly
alike, so that the extra-currents from them neutralised each
other. The third consisted of a wire folded back on itself,
whose self-inductance was small and could be easily calcu-
lated; it was found to be p = 13.194 mm. In opposition
to this acted the fourth resistance of the bridge, the system of
wires under observation. This was stretched out on the floor
SCIENCE ENGINEERINGHE