218 Dr. L. J. Blake on the electrical Neutrality of 
and disk C at equal temperatures, but above the room- 
temperature, so that copious evaporation took place without 
condensation. The flame used in heating remained con- 
tinual^ outside the box*. 
It is necessary to free the surface of the liquid from dust- 
particles, and to avoid as much as possible air-currents within 
the metal box during the experiment. Moreover no minute 
drops must be tossed up during rapid evaporation. In these 
experiments the liquid experimented upon was in the first 
place electrified to a determined potential, and was swung 
under the condensing-disk C. B, and therefore C, had been 
previously insulated ; and A, distant ^ millim. from B, had 
been connected with the earth. Next, after 3 minutes the 
liquid was swung away from C. If a convection of electricity 
from the surface of the liquid to C had occurred, A would 
have fixed it upon B, and would have been itself charged 
with the opposite kind of electricity. After A was then 
insulated and separated, the presence of any fixed electricity 
upon A, and therefore also upon B and C, would have been 
shown by a deflection of the electrometer-needle connected 
with A. The liquid was electrified by a battery of 480 zinc, 
distilled water, copper elements (=404 Daniells). The de- 
flections, in millim. scale-divisions 
following table. 
Liquid, 
room-temp. 
Plate C, 
room-temp. 
Distilled water. < 
observed are given in the 
Liquid, 
100PC. 
Liquid, 
100° C. 
Salt- solution, ( 
(13per cent, sodium < +4 
chloride). (^ 
Alcohol, J" 
absolute. | 
Sulphuric acid, f 
concentrated. \ 
Charge 
Charge 
r 
Sea-water 
(Baltic). 
Plate C, Plate C, 
room-temp. 100° C. 
+ 480 elements. 
+ 2 
+ 480 elements. 
+ 5 
+ 2-5 
Charge +480 elements. 
+ 1 
Charge —480 elements. 
-4 
Charge +480 elements. 
+ 7-5 
+ 5 
Charge —480 elements. 
-4 -2 -5 
-7 -4 -5 
-6 -6 -4 
* See note page 213. 
2-5 
