124 
PROFESSOR R. THRELFALL AND MR. J. H. D. BREARLEY 
ductivity, which was further shown by the galvanometer needle kicking slightly from 
time to time. The following table will indicate the effect we mean ; we often 
observed it, but on this occasion the magnetic conditions were so steady that we are 
able to be quite certain that the effect is not to be explained by accidental irregularity. 
When taking the sensitiveness of the instrument, within a few minutes, not a trace 
of such an effect was to be observed, and the insulation of the wire, &c., was found to 
be perfect, as far as our methods would show. 
Table showing Irregular Conductivity of Sulphur Film containing a Mixture of 
Soluble and Insoluble Sulphur. 
Date , Nov. 11, 1892. Voltage, 268'4. 
Sensitiveness, 5 - 43 X 10 12 amperes. 
Temperature of air, 19 0, 9 C., —of sulphur, 20°'3 C. 
After the voltage has been applied long enough for the sulphur to take up a steady 
state (say 20 minutes) 
A-B, double elongation, 6 divisions, 
B-A, „ 
18 
. , 
A-B, 
>: 6 
5 ' 
B-A, 
6 
5 : 
A-B, 
s, b 
5 5 
B-A, 
„ 16 
55 
A-B, 
„ 33 
55 
B-A, 
29 
,, *- J 
5 5 
The capacity was found to be exactly the same as before, and the plates regarded 
as a condenser gave a bright spark on discharge. 
This irregular conduction (though not always so well-marked) was generally 
observed, and may be considered as a natural phenomenon. 
The sulphur was then tested for residual charge in the manner formerly described. 
Sensitiveness of electrometer was 41 divisions per Clark cell: the insulation of all 
the apparatus was so good that no corrections had to be applied for leakage. After 
charging for five minutes with a voltage of 238‘6 volts, the residual charge gave a 
deflection of 9‘5 divisions in one minute, and 11 divisions after two or three minutes 
more. If we take 10 divisions as a basis of calculation, the residual charge is 
•147 per cent, of the initial charge, or between three and four times as much as we 
got before. But the conductivity is, say, a thousand times greater, which seems to 
show that there is no accounting for the residual effect by considering the con¬ 
ductivity alone. If we adopt Maxwell’s calculation as a basis, then the variation 
Specific Resistance „ , , , . , . 
v-:—————;- from layer to layer is greater m the case under considera- 
Specinc inductive Resistance “ ° 
tion than in that formerly dealt with. The conductivity of the film was not great 
