ON THE ELECTRICAL PROPERTIES OP PURE SULPHUR. 
73 
Specific resistance of prismatic sulphur at 112°T C. = 7‘39 X 10 1 ' 2 ohms. 
Specific resistance of prismatic sulphur at 69° C. = 3'93 X 10 15 ohms. 
Below 69° C., the conductivity ceases to be measurable. With regard to the 
observation at 69° C., we show that this is not the value for pure sulphur perfectly 
prismatic. With respect to the value at 112*1° C., all depends on whether the 
sulphur is heating or cooling; but, in any case, we consider it is probably too low. 
It is further stated that the same prismatic sulphur left to itself at ordinary 
temperatures, d'evitrifies and assumes an appreciable conductivity. Thus:— 
After one day, specific resistance at 17° C. = 1*170 X 10 15 ohms. 
After two days, specific resistance at 17° C. = 7'05 X 10 14 ohms. 
This is contrary to our results. Our impression is that probably the sulphur 
was a mixture of monoclinic and insoluble sulphur, that surface effects were not 
sufficiently guarded against, and that the sulphur was probably impure. But here 
again the brevity of the account disarms criticism; we can only say that the 
results do not agree with ours in any way. There are other remarks on the con¬ 
ductivity of octahedral sulphur, which is said to be zero, and on the conductivity of 
sulphur in the liquid state, which we have not yet investigated. 
E. Dtjter, ‘C.B.,’ vol. f 06, p. 836. Some experiments with an induction coil on melted 
sulphur. The author found traces of action both on gold and platinum electrodes. 
J. Monckman, ‘Proc. Boy. Soc.,’ 1889, vol. 46, p. 136. The most complete record of 
the electrical properties of sulphur hitherto published. He used a voltage of about 
60 volts, and a high resistance galvanometer. The electrodes were of gold or carbon, 
and the paper is more concerned in establishing qualitative properties than absolute 
quantitative results. The results are more valuable than any of those hitherto 
mentioned, because the purification of the sulphur is more fully dealt with. All the 
numerical results refer to melted sulphur, and therefore will not be dealt with here. 
The most novel observation is that the resistance of “soluble ” sulphur depends on the 
light falling upon it, a result which is inconsistent with that of a number of 
experiments, designed to test the point by one of the authors, with the assistance of 
Mr. J. B. Allen. 
Specific Inductive Capacity of Sulphur. 
An exhaustive list of results up to 1883 is given by Gordon (“ Electricity and Mag¬ 
netism,” vol. 1, p. 134 (Table)). The lowest results are those of Faraday and Gordon, 
viz., 2'24 and 2'58 ; and the highest recorded values are those of Boltzmann, from 
3'84 to 4*773, along a particular axis in octahedral sulphur. Values given by 
Wullner and Boltzmann (by condenser method) lie between the above limits. It is 
clear that the value of the specific inductive capacity of sulphur requires further 
MDCCCXCVI.—A. L 
