Evening star. [volume] (Washington, D.C.) 1854-1972, 1874-10-17
FROsT AND SNOW.

DID our readers ever glance at a snow CRYSTAL.
IL requires quick and prompt manipulation TO
on the river" Is not q whit more readily dis
solved than ii is under ma gnify ing glass Once
seen, a snow cry stall will never be forgotten. Ii
is one OF the most beautiful and elegant of
foTBs-or rather a ccDRerIes of forms-iu the
world. The delicate fern-hke films which the
frost leaves on our window panes during some
extra cold night shows us the nature OF the crys-
tshZstons. Examine such an ice crystal on the
window with an ordinary pocket lens, and mind
you do so before the steam of your breath dts
solves Ii away, and you will confess you never
imagined IL was so really beautiful. But these
are not TO be compared, for beauty, with the
minute crystals of which there are hundreds
entering into the structure of an ordinary snow
fake.
1t is q law OF crystallography that geometri-
caily shaped crystals such as we see in spar"
&C., can only be formed when the particles
entering into their composition are free to
arrange Themselves according to certain opera
tive laws. You can never have q crystal of
any kind unless this condition has been COM
piled with. Let US see how the particles of
snow crystals fulfil this condition. They are
merely very minute atoms of frozen vapor.
The atmosphere through which that vspor was
difused has been chilled by cold, and its mois-
ture thus as certainly squeezed out OF it as If it
had beep saturated sponge pressed by the
hand. Had this cold been less intense, the par
ticles OF vspOr would have run together and a
rain shower would have been the result. But
as each minute atom of vapor was set free, the
cold froze II, and thus the whole atmosphere
became full of such infinitesimsl atoms.
no wonder that an approaching snow storm
should be heralded by dense, dark, leaden- col
Ored clouds. II vapers are frozen at a great
he'ght above the earth, then We may expect to
nave large snGvhskes, for the crystals are
formed by the particles of frozen vapor ar
ranging themselves in certain directions, and
thus forming true crystals Each snowflake Is
group of such crystals. Sometimes the large
snOwfakes collect in an upper part of the at
mOsphere, and in falling toward the earth they
have to pass through a warmer stratum of air
which half melts them. In such case 1t Is not
snow visited with, but sleet. on the tops
Of cur hills and mountains snow seldom or
never falls SIS flakes, but always as fine granu.
lar particles, almost like -four dust. Each part
icle, however, is not the Iess q crystal, for the
hneness is due TO their being collected high up,
and through their not having lad time or space
TO group themselves into snOwfakes.
In all those parts OF the world where the
ground is above the snow line, the excess of
moisture cannot be got rid of as in rain-the
only way II can be precipitated is as snow. II ad
it been as rain, the excess of the latter would
have collected as mountain rils and torrents
and would have fed the rivers which every map
shows us branching and subdividing, and origi-
mating in billy districts. In this wsv the excess
would have found its way to the sea. Now there
remains exactly the same necessity for getting
lid of the moisture in the shape of snow as there
does in its other form as rain; In our latitude
the coolest summer is generally warm enough
TO completely melt the last winters SHOWS be-
fore those of another accumulate. Hence orr
ordinary water channels are sufficient to carry
on the snow water. But in those places where
he summers heat Is not ssffi cient TO melt the
winters snow, it is evident that If there were no
means of disposing of the excess, analogous to
that by which rain gets carried to the sea there
would be such constant accumulation of snow
that in time our mountains would owe their
enormous height entirely to its having been
piled up during successive winters.
There is known means of getting rid of
SNOWFALL as or rainfall. It is no longer in action
In Great Britain, but it was SO during a geoiog-
zeal period called the "Glacial, ;" when the beds
"A " n n hi "a fArF ,gto
of our agricultural counties were deposited.
This agency is called a glacier, or ice river
The successive accommodations of fine snow press
down the lowest and Oldest layers into ice, which
ice is constantly melting and freezing, in a mo-
lecua ar form, so that tn g presence of snow accu-
mutation above will force a tongue of viscid ice
some thousands OF feet below the actual snow
line. Such glaciers are abundant in the Alps,
aud in some arctic localities we find them actu-
ally on the sea level. They bring down masses
OF rock which have fallen on the surface, or
which have tumbled into the 'Ecrevasses'' or
cracks caused by the more rapid movement OF
the middle of the ice rivers than along the sides,
where the friction of the rocks interfsTes.
Such boulders are frequently frozen in the
mass Of ice, and thus act as natur al growers
and polishers, to scratch and striate the solid
rock over which the ice river slowly moves. At
length they reach the foot of the glacier, where
the warmth Is such that 1t melts the ice as fast
as II IL pushed forward. Here, of course, ordi-
nary streams of muddy water take the place of
the ice, and thus the actual moisture is convert
ed from ice to water, to be carried away to the
seq as 1t had been originally rainfall. A huge
hank OF material-mud, gravel and angular
scratched and polished fragments of rocks of
various klnds-accumuates at the foot of the
glacier, where ii is call.d a n0rdine. Or wemay
hnd such moraines along the sides OF such ice
rsines NAV exist as geographical features for
ages after glacier has changed its course, and
thUs serve as a Trustworthy record of former
state OF things -CdsseUs K1gdsiHe.