AND STRAIN ON THE ACTION OF PHYSICAL FORCES. 
153 
an electromagnetic solenoid to bismuth is very much smaller than is the case with 
iron, nickel, or cobalt, it is proper that rather fuller details should be given in 
describing the results obtained so that the trustworthiness of these results may be 
duly estimated. 
A bar of bismuth, 25 centims. in length and ’330 centim. in diameter, was provided 
with copper terminals of the same diameter, and connected up with a similar bar to 
the “ bridge,” as shown in fig. 20. In this figure the relative dimensions of the bismuth 
bars and their copper terminals, as well as the mode of establishing the “ bridge,” are 
sufficiently shown. To the binding screw, a, a silk-covered copper wire, c, was soldered 
to connect the bars with the galvanometer, whilst the two binding screws, b b, were 
provided with silk-covered copper wires leading to the poles of one Grove’s cell and to 
two resistance coils of 100 ohms each in the usual manner. The coil A was employed, 
and the bars were arranged in the same manner and with the same precautions as the 
iron wire used in Experiment LIX., except that now it was necessary to dispense with 
the glass tubes in order that the bismuth bars could be slipped into the copper vessels 
through which the water flowed. The bars were, however, well varnished and covered 
with tissue-paper so as to ensure thorough insulation. The B.G. was kept closed and 
the alteration of resistance observed in the same manner as with the nickel and cobalt 
bars. The M.C. was produced by 13 Grove’s cells, and the deflection of the needle of 
the tangent galvanometer was 22’5°. The readings given below are determined in 
each case as usual from three consecutive readings ; thus, a b c being three consecutive 
readings the recorded number is 
N umber of trial. 
Deflection of galvanometer- 
needle in scale divisions. 
+ signifies apparent increase of 
resistance on magnetization. 
1 
10’00 + 
2 
10-00 + 
3 
9-50 + 
4 
10-25 + 
5 
11-00 + 
6 
10-50 + 
7 
10-25 + 
8 
10-75 + 
Mean 
10-23 + 
Mdccclxxxiii. 
X 
