THE SPECIFIC INDUCTIVE CAPACITY OF A DIELECTRIC. 
17 
Turpentine. 
. . '00035 for temperature 
range 
from 10° 
to 17' 
Benzene 
. . -00040 
5 ) 
10 
„ 39 
Benzylene . 
. . -00037 
5 9 
25 
„ 39 
Glycerine . 
. . -00018 
20 
„ 48 
Thus, it appears that although the two rates of change for Glycerine present 
no similarity whatever, those of the rest of the four are in a ratio not very far from 
I to 2, the approach being nearest in the case of Benzylene. 
Appendix. 
(Received October 18, 1889). 
A suggestion having been made that, as the opposite effects of rise of tempera¬ 
ture upon solids and liquids were observed by different methods, it would be 
well that both should be tested by the same method, a qualitative experiment was 
made on a solid by the method used for liquids, to see whether the result would agree 
with that already obtained. 
A cylinder of glass was placed between the quadrants and needle of the liquid 
electrometer, leaving the needle free to oscillate; and observations were taken 
at different temperatures, exactly as already described for the case of a liquid 
dielectric. The result was always an increase of specific inductive capacity with rise of 
temperature, All the precautions for insulation, &c., were observed as in the 
experiments already described. But the heating was not maintained long enough to 
secure that the glass had acquired the fidl temperature of the air in the bath ; 
so that the results obtained are only qualitative, the change being less than that 
corresponding to the temperature indicated by the air inside the bath. In one case, 
where the heating had lasted several hours, the rate of change rose as high as ‘0024 
per degree for a range of 50° C.,a result sufficiently close to that obtained for glass by 
the other method, 
D 
MDCCCXC. — A 
