1
31
KINETIC ENERGY OF ELECTRICITY IN MOTION [1]
l=35,892,
P=179,960, J'= 0·7213,
q=0.1323,
p'
P
= 5.330,
J =
=
0.1348.
The calculated inductions may be regarded as exact, as their
error can hardly amount to 1/100. The probable errors for
the quantities J and J' may be deduced from the experiments,
and are found to be
for J' 0.0092, for J= 0.0019.
=
If we here assume that both strengths are measured
wrongly to the full extent of the probable error, and both in
the unfavourable sense, that is J too small, J' too large, we
get
m< 179.960 (5·330.
0.1367
0.7121
-
- 1),
m < 4190,
μ< 0·0077 mm².
3. In the second series of experiments with rectilinear
wires we had
P=185,240, J'1111,
1 = 35,892,
P'
q = 0·3300,
P
= 5'0367, J = 0.2196.
In determining J only experiments from No. 8 onwards have
been used. The probable errors resulting from the experi-
ments are
for J' 0.026, for J= 0.0040.
The same assumption as above gives here
m < 185,240 (5·0367.
0.2236
1.085
- 1),
m < 7042, μ< 0·0323 mm².
The limit here is not so close as in the preceding experi-
ments, chiefly because there q, the cross-section of the wire,
was less, and thus the conditions were more favourable for
rendering prominent the effect of mass.
Hence, using the first series of experiments with rectilinear
wires as being the best, we obtain this result :—
SCIENCE ENGINEERING LI-