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chance to walk over a plain of newly formed ice before any
snow has fallen, you will be astonished to find every footstep
impressed in the mass just as in melting snow. If
unacquainted with the fact, you will in vain try to understand, how
the solid ice can be in a melting condition at a temperature
of —40° C or still more» [Weyprecht], The specimen of
ice examined in series VI of the following chapter and
represented in curve VI of plate 21 claims to be a representative
of this kind of polar ice. It is formed by sudden freezing of
ocean water of ordinary saltness from the Siberian sea and
itself contains O.649 p. c. of chlorine, according to the titration.
The plastic properties of such ice, described by
Weyprecht, will be found to correspond to a premature
contraction of volume, which begins already at —20° C. The
preceding diminution of expansion dates from a stage of
temperature far beyond — 20° C, the limit of my investigations.
We may now understand, why people of the trade are so
very particular about the locality, from which the ice of
commerce is taken. Everbody knows, that ice from the open sea
would not do for the market, but -I dare say, that everybody
does not know the reason why. Somebody may hint, that
ice from salt water must be disagreeable to the taste, but this
is far from being always the case. The most refined palate
will fail to detect the slight saltness of old sea-ice. At Cloven
cliff, northwest of Spitzbergen, I have collected blocks of ice
from the polar drift-current, which contained less than one
fourth of the amount of chlorides, which is found in the
drinking water of Stockholm. It is solely on account of the
physical properties accompanying this diminutive percentage
of salt, that sea-ice is rejected by the trade. Only the almost
chemically pure ice, produced by freezing of inland lakes,
deficient in chlorides etc. will bear transportation without
crumbling and conserve the glass-like hardness and
transparency, which is an indispensable condition of ice as an
article of consumption and of luxurj7.
Any physicist, familiar with the use of Bunsen’s ice
calorimeter, will also, like the author, be familiar with the
capriciousness of this instrument. Bunsen prescribes, that
the calorimeter should be placed in a big vessel filled with
entirely pure snow. Although I have had abundant quantities
of the purest snow at my disposal, I do not hesitate to
declare, having tried during a whole winter to obtain reliable
results with the original arrangement of the inventor, that
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