the Congelation of id fiver. ^Si 
fcCUy cooled, tne quickfilver melted away under it in drops ; 
and the fame thing happened when the metal was touched 
“ with the finger, by which alfo the finger was immediately 
“ benumbed. In our warm room it thawed on its furface ora- 
“ dually, by drops, like wax on the fire, and did not melt all 
“ at once. When the frozen mafs was broken to pieces in the 
“ cold, the fragments adhered to one another, and to the bowl 
“ in which they lay. Although the froft feemed to abate a 
“ little toward night, yet the congealed quicklilver remained 
unaltered, and the experiment with the thermometer could 
“ fhll be repeated. On the yth of December I had an oppor- 
“ tunity of making the fame obfervations all day ; but fomc 
44 hours after fun-let a north- well wind fprung up, which railed 
“the thermometer to -46°, when the mafs of quicklilver 
“ began to melt.” 
Before this obfervation of Dr. pallas’s, no perfon had feen 
or handled quicklilver frozen by natural cold, fo as to fubmit 
the fact to the public with competent evidence ; but the cir- 
cumffances here related are fo pointed and confident, that 
even thofe who had doubted of M. braun’s experiments were 
now daggered, and began to believe. Indeed, it was fcarcely 
poflible to luppofe any miflake, when Dr. pallas had two 
whole days to repeat and vary the experiments at his leilure. 
But befides removing all doubts upon the congelation of quick- 
filver, thefe obfervations tended to fhew, within certain limits, 
the degree of cold neceffary for that elFeft. It was evident that 
the freezing point muff be fomewhere above 70% becaule the 
thermometer’s graduation reached only fo low, and yet fome 
part of the mercury always congealed in the tube ; and as the 
lolid maffes did not begin to melt till the thermometer role 
to - 46°, that feemed to be nearly the point at which it pafles * 
from 
