Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-02-02

IL.
snowflake is an ice crystal or a cluster of such
crystals, and the shapes of these tiny gems
are infinitely varied No two specimens of ice
on our windoWpanes are exactly alike in pat
tern. HailStones show q remarkable diversity
OF architecture. Even the larger aggregates
of ice and snow exhibit an immense variety of
typical forms
Early this Winter came tidings from Alaska
The streams in that territory were, it was said
reversing the usual order Of procedure and
freezing from the bottom up instead of from
De top down!
Who discovered this mares nest am unable
TO say, but the tale was widely broadcast
that my mail was burdened with appeals for
an explanation. What actually happened was
nothing new, strange or unusual. The forma-
ton of ice at the bottom of streams when the
water above is unfro7en is process with which
science Is well acquainted, though, for obvious
reasons, the existence of ice so located is not
usually noticed by the casual observer
Ice thus formed at the bottom of a body of
water is called anchor ice" In temperate
ATTITUDES its formation is due to the cooling of
the bed of the stream by rapid radiation of
heat through the water. 1t forms only at night
and under clear sky. Anything overhanging
the water-Such as a bridge, for example
checks this heat loss and prevents the ice from
forming
In high ATTITUDES anchor ice may be pro-
duced in another way. Where the soil below
a certain depth is permanently frozen, as it is
In q great part of Alaska, the bottom of a
stream loses heat not merely by radiation to
the sky above, but also by conduction to the
ground below. Thus it may cool below the
freezing point before the water does SO at the
surface, and the cold bottom will then cause
ice to form next to it.
Prof. Barnes of McGin University has
studied anchor ice for years in the River St
Lawrence. He tells us that a layer five feet
thick may freeze in single night. A slight
warming of the water after sunrise detaches
N1lis ice and permits it to rise to the surface
often bringing up big rocks from the bottom.
Boats are sometimes surrounded and caught
by these rising masses and are carried down
into the rapids before they can be extricated.
A MOTHER prank of nature that arouses
curiosity every Winter is the formation of
vertical columns of needles of ice in moist
graVely SOIL Clusters Of these columns may
sometimes be seen on cold mornings on a patch
OF bare ground, uplifted to height of an inch
or more and often capped with small stones or
particles of earth. The ice is pushed up by
the capillary" or wicklike action of the soil
on its contained water and also by the expan-
sion OF the water in freezing.
One of the rarest Spectacles of cold weather
is the lice spine," some examples of which
have recently been described by Mr. F. E.
MattheS OF the United States Geological Sur
vey. In one case tiny puddle of water had
gathered in shallow cavity drilled in rock
at quarry. With drop in Temperature a
sheet Of ice formed over the surface of the
puddle and eventually the whole body of water
turned to ice. AS it was confined by the rock
1t could expand only in an upward direction
but instead of the whole surface being lifted
small vertical spine of ice pushed up in the
middle to height of a couple of inches On
another occasion Mr.. Matthes found a large
number of such spines projecting from small
frozen pools in cavities a rocky mountain
slope in the Yosemite Valley. In this case the
spdnes were not vertical but were inclined at
various angles.
Walking through the woods on a frosty
morning you may discover a clump of dead
plant stems adorned with the strange append
ages known as "ice fringeS" The plant will
probably be a specimen of dittany (Cunila
orlganoides), which, for some unknown reason.
wears these ribbons far more frequently than
does any other member of the vegetable king
dom They consist of thin, curving sheets of
Ice about as thick as q knife blade half an
inch to two inches wide and sometimes six or
seven inches long. One or more may form on
q stem.
Ice fringes have been investigated by several
botanists and physicists, especially in recent
years by DIR. Coblentz of the United States
Bureau of Standards and DR.. Humphreys of
the Weather Bureau, but their origin is still
something OF mystery. The ice Is not de-
posted from the air, after the manner of boar
frost, but is formed from water that rises from
the soil through the dead stems Each fringe
begins as row OF separate hair-like CRYSTALS.
which merge into q continuous ribbon as thew
grow outward.
The cohesive character of moist snow, util-
lied by the juvenile sculptor in the making of
snow men, causes this substance to assume
naturally a number of striking FORMS Thus a
strip OF snow lying along a window ledge a
fence top or the branch Of tree will some
times slip down in the middle and hang in
feStoon fashion, supported only at the ends
This formation is called SNOW garland"
The delicate adjustment of temperature re-
quired to produce this freak-involving first
a slight melting of the snow and then prob
ably its refreezing-is doubtless of rare occur