the Congelation of QuickjWver* 383 
they lay. So likewife Mr. hutchins found the frozen quick- 
(ilver adhering to his cylinders and gallipot ; Profefifor blu- 
menbach to his glafs veil'd; and fimilar fads occurred to 
other oblervers. Hence the deceptions, already fo often men- 
tioned, from the kicking of the mercury in the ftems of ther- 
mometers. And this caufe of error can fcarcely ever fail to 
take place; for if quickfilver congealing in wide open vcffels 
adheres to them wherever it touches, how can it be expe&ed to 
remain loole when frozen in a narrow tube ? Now', fince quick- 
lilver, under thefe circumftances, retains the fame appearance 
as while fluid, from the polifh given to its furface by the 
fmooth glafs, it is no wonder that fuch frequent miftakes have 
been made relative to the height of the thermometer, both in 
experiments with artificial cold, and in meteorological obferva- 
tions. At the fame time it mull; be confeffed, that fuch a ten- 
dency to adhere, in a metal which contracts fo much in becoming 
lolid, is not a little difficult to explain, ur.lefs we may fuppole 
it to be the immediate effecl of the cryfkillization. 
Quicklilver, with all its other qualities of a perfect metal, 
feems from Dr. pallas’s, and indeed mod; of the experiments, 
not to be completely malleable, but rather apt to break under 
the hammer. Perhaps it has never been fufficiently cooled to 
poffefs its metallic properties in perfe&ion ; for with refpect to 
its melting point it may be confidered as having always been 
hot, that is, heated near to fufion, a ftate in which other 
metals undergo a very fenfible change in their properties. But 
when mercury congeals in veffiels which confine its lurface, it 
feems to become more malleable than under a loofe crvftalliza- 
tion. 
Dr. pallas’s travels lafled from the year 1768 to 1773, 
during which time this of the beginning of December, 177 2, 
Vol. LXXJTh E e e feem 
