ON THE ELECTRICAL PROPERTIES OF PURE SULPHUR, 
117 
conduction occurs also when the conduction is superficial, but that it is a real pheno¬ 
menon of the conduction through sulphur as well. The temperature was constant 
between 75°'5 and 74°'3 0. The capacity appears to be absolutely the same as 
before, i.e., within *3 per cent. 
The temperature raised to 99°'8-100° C. There now appeared to be a slight fall in 
capacity, say *3 per cent., but it was so small as to be quite uncertain. 
The following resistance results were obtained :— 
Double deflexion of 147 
9 9 
9 9 
22-5 
4-5 
9 9 
99 
divisions at 108° 
99 
111 ° 
c. 
c. 
113°7 0. 
110°‘5 C. 
Six experiments. 
Four experiments. 
Six experiments. 
Five experiments. 
The sensitiveness of the galvanometer had been reduced to one division for 
2'2 X 10” 11 ampere for the sake of rapidity of observation. The specific resistance 
(mean of above) is about 7 X 10 35 C.G.S., but we lay no stress on it, for on applying 
the capacity test it was found that the plates had come apart. 
The results with this film may now be summarized as follows :— 
Film of September 14, 1892. 
Thickness, ‘02431 centim. 
Area (effective), 156‘645 square centims. 
Kind of sulphur, either perfectly soluble, or containing less than 1 part in 100,000 
insoluble. 
• Crystals, monoclinic (aged monoclinic) and octahedral. Optic axis in plane of film. 
Melting point, 119°*5 C.-120°'l C. 
Specific inductive capacity at 18°*8 C., corrected in terms of Dr. Mujrhead’s 
standards. 
By ballistic method, 3*697. 
By instantaneous De Sauty method, 3708. The iatter value to be 
preferred ; capacity constant up to 100° G\, indicating small temperature 
increase of specific inductive capacity. 
These values were obtained with a voltage of 40 Clark cells. 
Residual charge with 300 volts, after charging one minute and discharging one 
minute, '03 per cent., say. 
Specific resistance at 20° C. by electrometer method, six Clark’s, say 1 X 10 28 C.G.S. 
Possibly entirely surface action. Exposed to damp air, resistance diminished in our 
apparatus 1000 fold. 
Specific resistance by galvanometer method with a voltage of 291 volts greater 
than 1*4 X 10 27 C.G.S. from 18° to 50° G, At a temperature of 75° C. the specific 
