Electricity by Evaporation. 213 
and insulated, became very slowly charged in the presence of 
the tinfoil upon which the condenser rested. When B was 
left in the evening connected with the earth, and insulated 
the next morning, there was always found upon it a charge 
which produced a deflection from 10 to 17 millim., and 
under similar conditions always in the same direction. In 
15 minutes B became charged to a potential corresponding 
to 0'5 and upwards to 2 millim. This peculiar electric 
action, which was always present, must evidently be taken into 
account, and is so in the following experiments. This action of 
the condenser having been determined, the inner porcelain 
dish was filled with the liquid to be experimented upon, and 
the sand-bath heated to 100° C. The flame employed for heat- 
ing was then wholly removed*. A platinum wire inserted 
through a narrow glass tube fused around it formed metallic 
connexion between the plate B and the liquid. By the glass 
the steam was prevented from coming into contact with the 
wire. The condenser-plate A was separated ^ millim. from 
B, and, together with the needle of the electrometer, connected 
with the earth. After 10 or 15 minutes of copious evapo- 
ration, A was insulated, and then separated from B. The 
electrical condition of A, and consequently of B, could be 
determined through the deflection of the electrometer-needle, 
and any difference of electrical condition at the begining and 
end of an experiment could be observed. The liquid used in 
the experiments was at first cold, and afterwards heated to 
rapid evaporation; but otherwise the conditions were un- 
changed, so as to be wholly independent of any disturbances 
possible from the nature of the apparatus itself. The following 
tables show the deflections at a distance of 3 millim. between 
the mirror and scale. 45 millim. scale-divisions denote a 
charge of 1 Daniell upon B. The deflection corresponding 
to 1 Daniell is here less than in the experiments mentioned 
above, because A is not charged directly, but indirectly 
from B. 
* A line of experiment which I have not at the present time finished 
seems to indicate quite clearly the production of electricity in every 
flame. It was hence found necessary before each observation to extinguish 
the flame employed, because of its disturbing influence ; owing to the pre- 
sence of the sand-bath, however, the evaporation was not interrupted. 
