130 
PROFESSOR R. THRELFALL AND MR. J. H. D. BREARLEY 
Half the battery (158 volts) was then applied the same way, and the resulting value 
was 
R = 1*5 X 10 13 , 
or Ohm’s law is not obeyed, though the steady state has been reached. 
The battery having been on one way for about two hours, it was thought a good 
opportunity for us to measure the effect of reversal, but, on this being done, the con¬ 
duction was too great to be observed for several minutes ; after, say, five minutes, it 
was still six times greater than before the battery was reversed. The full voltage was 
employed, and the resistance went on increasing, the current falling towards its 
former value for ten minutes, when observation had to be suspended. 
The effect of keeping the sulphur exposed to the action of the battery seemed 
so definite, and at the same time so curious, that it was thought worth while repeating 
the observations. This was done on December 1, 1892, at a temperature of 23'6° C., 
and a voltage of 288‘6 volts. After a preliminary test, to see that all was right, the 
positive end of the battery was put to the top sulphur plate and left, thus connected 
for one hour; there was then a mean throw on reversal through the galvanometer of 
28 divisions ; the current had become practically constant; the observations were :— 
Throw A — B 
5 5 
55 
B - A 
A - B 
B - A 
30 divisions 
2 7 
30 
25 
5 > 
5 5 
The telegraph pole in circuit only gave an elongation of 2 divisions. The mean 
elongation due to current through the sulphur is therefore 26 divisions. On reversing 
the battery, and observing, as quickly as possible—within about two minutes—the 
first two elongations were in the mean 92 divisions ; after five minutes (about) this 
fell to 71 divisions; after thirty minutes to 27 divisions. On being again reversed, 
the first elongations were 81 divisions ; after six minutes 75 ; and after thirty 
minutes 26 divisions. On again reversing the first effect was only 43 divisions, 
so that the sulphur behaves as if it got fatigued, and refused after a time to show the 
effect. If we suppose that the conduction is the expression of the breaking-up and 
re-arrangement of molecular groupings, such change being from more complex to more 
simple, this is the effect we should expect when the groups capable of giving way 
under the applied electric stress became weeded out. 
In these experiments of December 1 the smallest specific resistance observed was 
2T075 X 10 25 C.G.S., and the greatest 6 - 079 X 10 25 . 
The galvanometer sensitiveness was 1’32 X 10 -12 ampere per micrometer division 
of double elongation. 
Effect of rise of Temperature, December 2nd, 1892.—Temperature of sulphur, 
21'1 C. Normal resistance (i.e., after three minutes charging each way) was 
