434 E. Hungerford—Observations on Snow and Ice 
mber. This calculation assumes that all 04 See is 
ry lar 
ing pienomets 
Evaporation is then at most a very insignificant source of 
the ea oh electricity. 
ut further, the following facts are to be observed ? 
I. The deflections obtained in the experiments were always 
very small. (In the original readings it was easy to make an 
error of 0°1 a division, and thoug “the numbers in the tables 
are the means of Api observations, they are still affected by 
this error of rea 
2. The sign of the apparent charge is not always the same 
for the same liquid. This is particularly noticeable in the 
npn’ case of water. 
. The deflections were very much diminished when care 
the deflections, obtained with the evaporating dish dry, are 
usually much larger than the difference between these and the 
deflections, obtained when a liquid was evaporating. 
Ev idently then most of the electrification was due to other 
causes than evaporation, and the experiments do not tae 
trace any electricity whatever to this source. 
The problem of the source of the electricity of the atmos- 
phere is still unsolved. Evaporation, first proposed by Volta, 
whose theory until now has been better supported by experi- 
ment than any other, fails to account even for a small portion 
of it; and no other source has been proposed, which can as yet 
be scunideren sufficient. 
Art. LI.—Observations on Snow and Ice under pressure at 
iealeceia below 32° F. ; by EDWARD HUNGERFORD. 
from 1869 to 1871. hey have never been given in detail to 
the public. At the meeting of the American Association for 
the Advancement _ Seen ce, Pa) in Burlington, August, 1867, 
I gave a résumé of the observations made in the previous winter 
or spring, under he title of “A Preliminary Notice of Experi- 
ments on Snow at bole rencton below 32° F.” Of this paper 
a short abstract appears on page 39 of the proceedings of the 
Association for that year. I also gave at the get meeting, 
