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is owing to tlie excess of its snrface in com- 
,parison to the matter contained under it : 
as gold itself may be extended in surface 
till it will ride upon the least breaitb of air. 
The whiteness of snow is owing to the small 
particles into which it is divided ; for ice, 
when ponnded, will become equally white. 
According to Beccaria, clouds of snow dif- 
fer in nothing from clouds of rain, but in 
the circumstance of cold that freezes them. 
Botli the regular diffusion of the snow, and 
the regularity of the structure of its parts, 
(particularly some figures of snow or bail 
wliich fall about Turin, and which he calls 
rosette), show that clouds of snow are acted 
iiI)on by some uniform cause like electri- 
city ; and lie endeavours to show how elec- 
tricity is capable of forming these figures. 
He was confirmed in his conjectures by ob- 
serving, tliat his apparatus for observing 
the electricity of the atmosphere never 
failed to be electrified by snow as well 
as rain. Piofessor Winthrop sometimes 
found his apparatus electrified by snow 
when driven about by the wind, though 
it had not been affected by it when the 
snow itself was falling. A more intense 
electricity, according to Beccaria, unites 
the particles of hail more closely than the 
more moderate electricity does those of 
snow, in the same manner as we see, that 
the drops of rain which fail from thunder- 
clouds are larger than those which fall from 
others, though the former descend through 
a less space. 
AVere we to judge from appearances 
only, we might imagine, that so far from 
being useful to the earth, the cold humi- 
dity of snow would be detrimental to ve- 
getation. But the experience of all asres 
asserts the contrary. Snow, particularly 
in those northern regions where the giound 
IS covered with it for several months, fruc- 
tifies the earth, by guarding the corn or 
other vegetables from the intenser cold of 
the air,' .and especially from the cold pierc- 
ing winds. It has been a vulgar opinion, 
veiy generally received, that snow fertilizes 
the land on which it falls more than rain, 
in consequence of the nitrous salts, which it 
is stqrposed to acquire by freezing. But it 
appears from the experiments of Margraaf, 
in the year 1731, that the chemical differ- 
ence between rain and snow water is ex- 
ceedingly small ; that the latter is somewhat 
less nitrons, and contains a somewhat le.'s 
proportion of earth than the former; but 
lieitlier. of them contain either earth, or any 
kind of salt, in any quantity which can be 
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sensibly efficacious in promoting vegeta- 
tion. Allowing, therefore, that nitre is a 
fertilizer of land, which many are upon 
good grounds disposed utterly to deny, yet 
so very small is the quantity of it contained 
in snow, that' it cannot be supposed to pro- 
mote the vegetation of plants upon which 
the snow has fallen. The peculiar agency 
of snow, as a fertilizer in preference to rain, 
may admit of a very rational explanation, 
without recurring to nitrous salts, supposed 
to be contained in it. It may be ascribed 
to its furnishing a covering to the roots of 
vegetables, by which they are guarded from 
the influence of the atmospherical cold, and 
the interna! heat of the earth is prevented 
from escaping. The internal parts of the. 
earth is heated uniformly to the forty- 
•eighlh degree of Fahrenreit’s thermometer. 
This degree of heat is greater than that 
in which the w'atery juices of vegetables 
freeze, and it is propagated from the inward 
parts of the earth to the surface, on which 
the vegetables grow. The atmosphere be- 
ing variably heated by the action of the sun 
in different climates, and in the same cli- 
mate at different seasons, communicates to 
the snrface of the earth, and to some dis- 
tance below it, the degree of heat or cold 
which prevails in itself. Different vegeta- 
bles are able to preserve life under different 
degrees of cold, but all of them perish when 
the cold which reaches their loots is ex- 
treme. Providence has, therefore, in the cold- 
est climates, provided a covering of snow for 
the roots of vegetables, by which they are 
protected from the influence of the atmos- 
pherical cold. The snow keeps in the in- 
ternal lieat of the earth, which surround* 
the roots of vegetables, and defends them 
from the cold of the atmosphere. 
Snow grotto, an excavation made by 
the waters on the side of Mount Etna, 
by making their way under the layers of 
lava, and by canying away the bed of puz- 
zolana below them. It occurred to the 
proprietor, tliat this place was very suit- 
able for a magazine of snow : for in Sicily, 
at Naples, and particularly at Malta, they 
are obliged, for want of ice, to make use 
of snow for cooling their wine, sherbet, and 
other liquors, and for making sweetmeats. 
This grotto was hired or bought by the 
Knights of Malta, who having neither ice 
nor snow on the burning rock wliich they 
inhabit, have hired several caverns on Et- 
na, in which people, whom they employ, 
collect and preserve quantities of snow, to 
be sent to Malta when needed. This grotto 
