othnia, where the quantity
of salt in the water amounts in general to one fourth only of that in
the ocean, the entire surface freezes over in winter to the depth of 5
or 6 feet. Stones are thus frozen in, and afterwards lifted up about 3
feet perpendicularly on the melting of the snow in summer, and then
carried by floating ice-islands to great distances. Professor Von Baer
states, in a communication on this subject to the Academy of St.
Petersburg, that a block of granite, weighing a million of pounds, was
carried by ice during the winter of 1837-8 from Finland to the island of
Hockland, and two other huge blocks were transported about the years
1806 and 1814 by packed ice on the south coast of Finland, according to
the testimony of the pilots and inhabitants, one block having travelled
about a quarter of a mile, and lying about 18 feet above the level of
the sea.[302]

More recently Dr. Forchhammer has shown that in the Sound, the Great
Belt, and other places near the entrance of the Baltic, ground-ice forms
plentifully at the bottom and then rises to the surface, charged with
sand and gravel, stones and sea-weed. Sheets of ice, also, with included
boulders, are driven up on the coast during storms, and "packed" to a
height of 50 feet. To the motion of such masses, but still more to that
of the ground-ice, the Danish professor attributes the striation of
rocky surfaces, forming the shores and bed of the sea, and he relates a
striking fact to prove that large quantities of rocky fragments are
annually carried by ice out of the Baltic. "In the year 1807," he says,
"at the time of the bombardment of the Danish fleet, an English
sloop-of-war, riding at anchor in the roads at Copenhagen, blew up. In
1844, or thirty-seven years afterwards, one of our divers, known to be
a trustworthy man, went down to save whatever might yet remain in the
shipwrecked vessel. He found the space between decks entire, but covered
with blocks from 6 to 8 cubic feet in size, and some of them heaped one
upon the other. He also affirmed, that all the sunk ships which he had
visited in the Sound, were in like manner strewed over with blocks."

Dr. Forchhammer also informs us, that during an intense frost in
February, 1844, the Sound was suddenly frozen over, and sheets of ice,
driven by a storm, were heaped up at the bottom of the Bay of Taarbeijk,
threatening to destroy a fishing-village on the shore. The whole was
soon frozen together into one