ON THE ELECTRICAL PROPERTIES OF PURE SULPHUR, 
99 
. divisions. Since it was described in the ‘ Philosophical Magazine/ and before it made 
its appearance in connection with this work, one of the coils developed a fault. It 
was therefore replaced by a coil of much fewer turns and only a few hundred ohms 
resistance, which we happened to have by us. The diminished sensitiveness is due to 
this cause. It was rather unstable and consequently difficult to observe ; owing to 
this, for the sake of security we have considered 10 scale divisions, instead of one, as 
the limit of effective sensitiveness. We could detect no current whatever throusrh 
the sulphur with this instrument and the voltage mentioned. 
The resistance is therefore certainly greater than 
551 
1-44 x 10" 10 
= 3'8 3 X 10 13 ohms at (say) 18° C. 
And the specific resistance is greater than 
190 
•05 
X 3'83 X 10 12 = 1'5 X 10 16 ohms (say) = 1‘5 X 10 35 C.G.S. 
This will be discussed in connection with other results. 
The capacity of the condenser formed by the sulphur plates was measured 
ballistically, or rather it was compared with the capacity of the same condenser, 
when the film had been removed and the plates separated to the same distance by 
bits of quartz needles. As this was an operation requiring time, one of the divisions 
of the microfarad condenser was used as a step. The result was that the specific 
inductive capacity arrived at was 3'5, which is about the mean of the values obtained 
by Boltzmann and Wullner, who probably used sulphur of this kind, i . e ., melted at 
a temperature not much above the melting-point, without any special precautions to 
ensure solubility. At this time we were not examining sulphur with respect to the 
resistance of its modifications, and the specific inductive capacity was taken as a 
check in order to be sure that the plates had not come apart. We were also 
anxious to see whether we could detect any sort of excessive current on charging, 
but the value obtained showed us that the closing current was quite normal. Of 
course the sulphur had been frequently stressed by the repeated application of a 
large voltage to insure its having reached a steady state. These experiments were 
partly preliminary; and we took no notice of the change of resistance on reversal, or 
of the action of time, for the very good reason that we got no measurable deflexion 
even with the large voltage applied. 
On taking the plates apart the film was almost perfect, and showed no sign of 
staining or of any action at all. The gilding of the plates, however, showed a few 
black specks where the copper had been acted on through the (spongy ?) gold. This 
is the only objection we have to this series of experiments. The results were after¬ 
wards confirmed in so far as resistance goes by the new galvanometer. 
o 2 
