Congelation of Quickffoer in England, 20^ 
melted into liquid globules. The flexibility of folid mercury 
was clearly to be obferved in this beautiful fpecimen ; for the 
external furface, particularly the upper thin rim of the con- 
cave part, was evidently bent by the firft gentle ftroke of the 
hammer. The globe of mercury in the other glafs, which 
was very fmall, exhibited nearly the fame phenomena, as ia 
the inftances before mentioned. 
It happened in thefe experiments of mine, contrary to what 
has generally occurred to others, that the mercury never funk 
lower than — 6o°, feldom fo low, in the thermometer, and 
but little below the point of mercurial congelation in the 
tubes of the thermometer glaffes filled nearly up to the orifice, 
with a view to fhew the con trad ion of mercury in becoming 
folid by its great defcent in the tube. On refleding on this 
circumftance afterwards, it occurred to me, that the further 
defcent of the mercury in thefe experiments was prevented not 
folely by the mercury freezing in the tube, the caufe com- 
monly afiigned, but rather by the quick formation of a fpheri- 
cal fhell of folid mercury within the bulb, by the fudden 
generation of cold. 
Dr. Beddoes exprefling a defire to exhibit folid mercury at 
his Ledure before his Clafs, I undertook to freeze fome at the 
Laboratory on March 12th lad, and now refolved to fatisfy 
myfelf refpeding the caufe which prevented the lower defcent 
of the mercury in my former experiments. In this, as well as 
the former, the mercury in a thermometer graduated to — 6o°, 
and likewife in a thermometer glafs, filled nearly to the orifice, 
which lengthened its ficale to near — 250 0 , funk only a few 
degrees below the point of mercurial congelation, and then 
remained ftationarv. After waiting fome time, I took the 
thermometer out of the mixture, and obferved the bulb appa- 
rently, full, and the fhort thread of mercury above unbroken. 
I i 2 I now 
