congelation longer, I plunged the fpirit thermometer into the
tube containing thg, native mercury. Having placed the apparatus
in the glafs with the refrigerant mixture for five minutes,
and tranfported it into a fecond glafs, the fpirit falling in the
thermometer to 32, we examined the mercury, and found it
frozen, although the fpirits of wine remained fluid, and the
thermometer flood at the fame degree, not only while the apparatus
remained in the cold mixture, but even after I tranfport'-
ed it into a warm room, and kept at the fame point, until a large
part of the bulb of the thermometer was uncovered by the melting
of the frozen mercury, drop by drop, into a glafs.
Fourth experiment on common barometer mercury.— The
mercurial thermometer ufed in the firfl experiment was plunged
into this mercury, and placed in the glafs of cold mixture, where,
having remained about five minutes, it was tranfported into a
fecond glafs, and there in four minutes the thermometer funk
down to 38, and remained flationary. There the fame Angular
phenomenon prefented itfelf that appeared in the fecond experiment,
with fome additions; viz. that the mercury was cooled
down to 5 i degrees below its freezing point on this thermometer
without becoming folid.
Fifth experiment with the fame mercury.— I froze a little of
this mercury without inferting a thermometer, in order to try its
malleability and fpecific gravity; it flattened under the hammer,
and of courfe is malleable, and funk in fluid mercury, which
{hews that it contrails confiderably in freezing, differing in this
4 circumflance
circumflance from common ice, which expands and fwims in c h a p .
IH.
water. 1---- -----
Sixth experiment on mercury adulterated with tin.— The fpirit
of wine thermometer was plunged into this mercury, and flood
at 32 when the mercury was frozen round its bulb.
Seventh experiment on purified mercury, was on the 10th of
January, 1785 (a repetition of a former one) in the prefence of
profeffors Pallas and Ferber, and other gentlemen, who attended.
I plunged the fpirit thermometer into a portion of Mr. Winter-
berger’s vivified mercury, and it fell to 32 degrees below O,
whilfl the mercury was freezing, aild remained there after it became
folid fb long as it flood in the frigorific mixture. I then
drew the thermometer out of the tube with its bulb froze into the
mercury, and hung it on a nail in the open air ; the metal melted
flowly in drops, and the fpirit flill kept at the fame point until
the greatefl part was thawed; we finifhed thefe experiments by
trying with the fpirit thermometer, what degree of cold was produced
by a frefh frigorific mixture, which appeared to be jufl 35
degrees below O.
From the whole of thefe experiments, I am difpofed to conclude,
that the freezing point of mercury is at 32 degrees below
O on Reaumur’s thermometer, or 40 of Fahrenheit’s, and that
common mercury does not freeze with a lefs degree o f cold than
what has been purified.
Eighth experiment.— February 1, 1785, a favourable cold of
15 degrees offering this evening, and being provided with fome
K k 2 revivified