ON THE ELECTRICAL PROPERTIES OF PURE SULPHUR. 
129 
10 minutes the battery was again reversed, and the deflection could now be read. 
Successive elongations on reversal of the galvanometer were 
252, 153, 153, 135, 108, 135, 
and as before the conduction was discontinuous, the galvanometer needle being thrown 
violently in the direction of increased conduction every few minutes, and then coming 
quickly back. The mean effect both ways reduced to a specific resistance of 2 X 10 24 . 
The film was then left for six days in the box with the phosphorus pentoxide, so as 
to get thoroughly dry, in case it was not so when the above results were obtained. 
The effect of time on the resistance was noted as follows 
Temperature of sulphur, 23'8° C. Voltage, 312 volts. 
On first applying the voltage + of battery to insulated plate the deflection 
corresponded to a resistance of 2 X 10 12 ohms. 
After three minutes this increased to 2 ‘6 X 10 12 ohms ; 
After twenty-five minutes to 3 X 10 12 ohms. 
The battery was then reversed, the initial effect died out in about three minutes, 
and during ten minutes’ observations were made so as to fix a mean value for the 
resistance, with the previous observations. 
Up to three minutes the resistance was 2’8 X 10 12 ohms. 
From three to ten minutes mean resistance was 4‘41 X 10 12 ohms. 
It is not easy to get very accurate values, because the change is always going on, 
and the discontinuous conduction makes it necessary to have several observations at 
each point. 
To test whether Ohm’s law was obeyed, we applied a voltage of 155 volts, and took 
the resistance both ways, up to three minutes, reversing several times first. The 
mean value was It = 4’69 X 10 12 , instead of 2‘6 X 10 12 , when we used the higher 
voltage. This result was probably affected both by the fact that the large voltage 
was applied first, and by the influence of the time action, though the latter was 
eliminated so far as possible. We do not think that the deviation from Ohm’s law 
observed can be explained away by any of these effects. A substance, whose 
conductivity may be a function of the quantity of electricity which has passed 
through it, can hardly be expected to obey Ohm’s law. 
On November 29, after the sulphur had been allowed to rest, the resistance was 
found, by reversing the battery (312 volts), and allowing the voltage to remain on for 
three minutes each way. The two sets of deflections were nearly equal, showing that 
a steady state had been reached. The resulting value was 
Resistance = 3‘fi X 10 J2 ohms. 
After one hour and twenty minutes this increased (with battery on one way only) to 
R. = 1-06 X 10 13 . 
MDCCCXCVI.—A. 
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