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‘“On the 11th of January,”’ says M. blumenbach, ‘“at
half after five in the evening, I put three drams of quick-
silver in a small sugar-glass, and covered it with a mixture of
equal parts of snow and Egyptian sal ammoniac. This mix-
ture was put loose into the glass, so that the quicksilver lay
[Seite 337] perfectly free, being only covered by it as with pieces of ice;
the whole, together with the glass, weighed somewhat above
an ounce. I hung it out at a window three stories high
upon a small roof facing the west, so that the glass was
freely exposed to the north-west; and I mixed with the snow
upon which it stood two drams more of sal ammoniac. The
snow and sal ammoniac in the glass soon froze in the open
air to a mass like ice: no sensible change, however, appeared
in the quicksilver that evening; but at one in the morning it
was found frozen solid. It had divided into two large and
four smaller pieces; of the former, one was hemispherical
and the other cylindrical, each seemingly rather above a dram
in weight; the four small bits might amount to half a scruple.
They were all with their flat side frozen hard to the glass, and
no where immediately touched by the mixture; their colour
was a dull pale white, with a bluish cast, like zinc, very
different from the natural appearance of quicksilver. I wished
much to break the glass immediately, and to try how these
bodies would bear the hammer; but desiring rather to have
witnesses of such a rare phaenomenon I refrained. The spirit
of wine, in an excellent thermometer made by brander,
stood at this time 10° under 0 of fahrenheit’s scale, which
was the cold of Upsal in 1740. Next morning, the 12th,
about seven o’clock, I found that the larger hemisphere be-
gan to melt, perhaps because it was most exposed to the air,
and not so near as the others to the sal ammoniac mixture
which lay beneath. In this state it resembled an amalgam,
sinking to that side on which the glass was inclined, but
without quitting the surface of the glass, to which it was
still firmly congealed; the five other pieces had not yet un-
dergone any alteration, but remained frozen hard, as I had
[Seite 338] observed them in the night. I now made haste to call some
of my friends, who came in time to see evidently all this
with me. They were the younger Dr. vogel, and Mess.
weber, wagner, and graumann. Toward eight o’clock
the cylindrical piece began to soften in the same manner as
the former, and the other four soon followed. About eight
they fell from the surface of the glass, and divided into many
fluid shining globules, which were soon lost in the inter-
stices of the frozen mixture, and re-united in part at the
bottom, being now exactly like common quicksilver.”’

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