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Table 3. Sea-ice.
Ice-water from Percentage of chlorine (titr.). Cl ( 100) S0.T
0.727. % O.OI45 %
1497 4365 4367 62.S..
* O.OOI9 % O.OOI4 % o.ooio %
Magdalena Bay Ice-fiord
» glacial ice v.floating) ioo 76.6..
From the above tables we may draw the following
conclusions :
I. Ocean-water is divided by freezing, not into pure water
and a more or less concentrated solution of ordinary sea-salt,
as was formerly believed, but into two saliniferous parts, one
liquid and one solid, which are of different chemical
composition.
II. The formation of sea-ice is chemically a selective
process. Some of the elements of the salt water are more fit
than others to enter into the solid state by freezing, those,
which are rejected by the ice, will be preponderating in the
brine and vice versa. Taking the relation Cl : S03 as standard
of comparison, we may characterize the most striking feature
■of the freezing process thus: that the ice is richer in sulphates,
the brine in chlorides.
III. The extraordinary variation both in saltness and in
■chemical composition of every individual specimen of sea-ice
and sea-brine, shown by the tables, depends upon a secondary
process or metamorphosis of the ice. Its ultimate tendency
is similar to that of the original act of freezing. The ice
seems to give up its chlorides more and more, but to retain
its sulphates. The cause of this metamorphosis has justly
been ascribed to the combined influence of time and
variations of temperature.
IV. The circumstance just alluded to forbids us to regard
the percentage of chlorine, found by titration in the ice or in
the brine, as a standard index of its entire saltness, but it
will prove invaluable to us, if we wish to form an idea of the
development of the metamorphosing action of time and
temperature on sea-ice. In the daily journal of the Vega for the
winter months 1878—79 many titrations 011 ice-waters and on
salt brines are recorded. The results are given in the fol-
20
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