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COXE’s TRAVELS IN RUSSIA, 693
and other gentlemen. I inferted the mercurial thermometer ufed in the latt experiment
in a portion of the purified mercury, N° 1, and placed them in the cold mixture: the
thermometer fell flowly to twenty-two and a half degrees, and was {tationary fome time,
whilft we perceived the mercury in the tube freezing round the fides, fo as to produce
a coating like tin foil in the Leyden phial; on tranfporting it to a fecond glafs of cold
mixture, the thermometer fell in five minutes to thirty-fix degrees, where it remained
{tationary during the time of its continuance in the mixture. What was remarkable in
this experiment, the mercury in the thermometer was ftill fluid, although its bulb was
frozen into that contained’ in the tube; for on reverfing the inftrument, the mercury
ran out of the bulb into the ftem. Now, here is a proof that mercury may be cooled
three and a half degrees below its freezing point without becoming folid.
‘© Third experiment with native mercury.—It having been afferted, that a thermome-
ter, filled with highly rectified fpirits of wine, is better calculated to determine the freez-
ing point of mercury, than one filled with the fame metal, becaufe it refifts congelation
longer, I plunged the {pirit thermometer into the tube containing the native mercury.
Having placed the apparatus in the glafs with the refrigerant mixture for five minutes,
and tran{ported it into a fecond glafs, the fpirit falling in the thermometer to thirty-two,
we examined the mercury, and found it frozen, although the fpirits of wine remained
fluid, and the thermometer ftood at the fame degree, (not only while the apparatus re-
mained in the cold mixture, but even after I tranfported it into a warm room) and kept
itat 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 firft experiment was plunged into this mercury, and placed in the glafs of
cold mixture, and after remaining five minutes, was tranfported into a fecond glafs, where
in four minutes the thermometer funk to thirty-eight, and remained ftationary. The
fame fingular phenomenon prefented itfelf that appeared in the fecond experiment,
with fome additions; viz. the mercury fubfided to five and a half degrees below its freez-
ing point on this thermometer, without becoming folid. :
“Fifth experiment with the fame mercury.—lI froze a little of this mercury, without
inferting a thermometer, in order to try its malleability and {pecific gravity ; it flattened
under the hammer, and of courfe is maileable, and funk in fluid mercury, which fhews
that it contraéts confiderably in freezing, differing in this circumftance from common
ice, which expands and fwims in water.
«* Sixth experiment on mercury adulterated with tin.—The fpirit thermometer
being plunged into this mercury, {tood at thirty-two when the mercury was frozen round
its bulb.
«* Seventh experiment on purified mercury, was on the roth of January 1785 (ares
petition of a former one) in the prefence of Profeffors Pallas and Ferber, and other gen-
tlemen. I plunged the fpirit thermometer into a portion of Winterberger’s vivified
mercury, and it fell to 32 degrees below 0, whilft the mercury was freezing, and re-
mained there after it became folid fo long as it {tood in the frizorific mixture. I then
drew the thermometer out of the tube with its bulb froze into the mercury, and hung
it ona nail inthe open air; the metal melted flowly in drops, and the {pirit ftill kept at
the fame point until the greater part was thawed. We finifhed thefe experiments by
trying with the {pirit thermometer, what degree of cold was produced by a freth frigo.
rific mixture, which appeared to be jult 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 4o of
Fahrenheit,
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