Sharp County record., 1881-04-14
Stones CIinging to Under Side Of Ice.


When the severe cold weather came
upon us so suddenly in November last
nv attention was called to curious
phenomenon in the Susquehanna River
here. Upon Thanksgiving Day, not far
below the dam which crosses the river
here, l noticed large number OF stones
clinging to the under side OF the ice.
The river there was two or three feet
deep, the ice at that time about three
inches thick. The stones were the
roundedriver stones and evidently came
from the bottom of the river. They
were of all sizes, up to those weighing
probably two pounds.
The phenomenon is not new one,
but it was displayed here upon so large
a scale, and the conditions accorded so
perfectly with those that the scientific
explanation demands, that it seems to
be worth while to call attention to it.
More than two hundred years ago
DR.. Plot, of Oxford, England, described
similar occurrences in the Thames, and
gave at least partial account of their
true cause. Its we'll known that water,
like most other substances, contracts
under the influence of cold until it is
reduced to temperature of thirty-nine
degrees. But if its temperature is low
cred still further it expands until reach.
ing thirty-two degrees, when it freezes,
by which its bulk is increased much
more than by its cooling from thirty
nine degrees to thirty-two degrees.
Hence it is that water begins to freeze
at the surface, since, when near the
freezing point, the coldest water, being
the lightest, is found upon the top, and
it is that which freezes first.
But when the weather is very cold,
and the different parts OF the stream
are thoroughly mixed by rapids or some
such mechanical action, the water may
be about the same temperature at all
depths, and be lowered altogether near
ly to the freezing point. In this case
the water will begun 10 freeze at the bot
tom, because it is stiller there, and per-
haps because the stones and bottom
have lost some heat by free radiation
and by contact cool the water. Al
though so much lighter than the water
this ice would not rise as soon as formed
for it would be frozen fast to the bot
tom and the stones lying upon the bot
tom. But as soon as its size gave the
cake of ice buoyant power enough it
would tear itself loose from the bottom
and the larger stones and rise to the
surface, carrying with it the smaller
stones and gravel. Then it would be
frozen in with the surface ice keeping
its curious load frozen fast to its under
surface.
In November the weather suddenly
became very cold, the thermometer
sank to three degrees, and the river
here was frozen over in one night, a
very unusual occurrence. Moreover,
the place where the phenomenon oc-
Cured was just below the dam, where
the current was swift and the river
rather shallow. All these would tend
to mix up thoroughly the whole mass of
the water. These circumstances seem
to show the above to be the true ex-
planation.
In the Thames stones weighing as
much as eight pounds have been known
to be raised up from the bottom of the
river in this way. Under favorable
conditions, and acting through long
time, the ice by carrying these mate
rials down streams must cause geologi-
cal effects which are not inconsiderable.
Lewisburg (Pa.J Cor. Scientific Anaert-
Cln