On the Formation of Hail. $5 
condensed particles of vapour, by the force of their own attrac- 
tion, being in proportion to its density. 
Under this impression, I can easily conceive (the resistance of 
the air being reduced by sudden expansion) that the condensed 
and frozen particles of vapour would be forcibly attracted to each 
other, and accumulate to the magnitude recorded in many of the 
hitherto apparently exaggerated accounts. 
Deprived, by my early entrance into the Navy, of opportunities 
of acquiring philosophical knowledge, I feel conscious of my in- 
capacity of determining a subject which does not admit of ocular 
demonstration ; but I think it will be aliowed, that the circum- 
stances of hail being unknown within the Arctic circle, where the 
electric fluid is inactive, and occurring most frequently with us 
when our atmosphere is charged with it, are near approximations 
to proofs that it derives its origin from electricity. And to prove 
that the sudden expansion of air will generate hail, I shall, in 
conclusion, give the following extract from a description con- 
tained in “ Gregory’s Mechanics,”’ of the Hungarian machine at 
Chemnitz, which discharges water from a mine by means of 
the compression and expansion of air. ‘‘ There is a very sur- 
prising appearance in the working of this engine. On opening 
the cock Q” (communicating with a vessel containing compressed 
air and water) “the water and air will rush out together with 
prodigious violence, and the drops of water are changed into hail 
or lumps of ice. It is a sight usually shown to strangers, who 
are desired to hold their hats to receive the blasts of air: the ice 
comes out with such violence as frequently to pierce the hat like 
a pistol bullet.” 
Having shown that artificial hail is produced by the sudden 
expansion of air, it remains for philosophers to determine, whether 
or not the electric fluid could cause the air to expand in the 
manner I have suggested. In the mean time, as I find that I 
am not the first to entertain an idea of the electrical formation 
of hail (but the reviver of a rejected theory), I must offer a few 
remarks upon the objections made to it in ‘* Rees’s Cyclopedia,” 
the work I have referred to for information on the subject. 
‘Though I may not have succeeded in proving the electrical for- 
mation of hail-stones, I think from the description given of them 
in the Cyclopedia, and the phenomena attendant on their fall, 
I shall be able to show the improbability of their being formed 
from drops of rain congealed by passing through a middle stra- 
tum of cold air, accumulating by aceidental adhesions in their 
descent to the enormous sizes so frequently recorded. After 
giving a short account of the theory entertained by Beccaria, the 
writer of this article says, that ‘all electrical theories ave inade- 
quate 
