the Congelation of Quickjilver. 
The other circumftance of which M. iiellant takes notice, 
that the fenfation attending this cold by no means correfponded 
with its effect upon a thermometer, pointed directly to the 
lame cOnclulion. When that inftrument is at 40° below o, the 
beams of houfes crack with a loud explofion, trees fplit and are 
killed, birds fall down dead out of the air, and it is with the 
utmoft difficulty that man, notwithftanding all his refources, 
can preferve the extreme parts of his body from being deftroyed 
by the froft. Now, if the cold had been increafed as far be- 
yond this degree, as it differs from the heat of boiling water, 
could M. Hell ant have expofed himfelf to the open air with 
impunity ? The analogy of all we know of cold declares the 
contrary : and though the power of animals and vegetables to 
relift variations of temperature has been found much greater than 
was formerly imagined, I think it would not be raffi to affirm, 
that in any part of our globe where the cold was carried to 
luch excefs, the whole fyftem of organized bodies muft periffi. 
Yet thefe obvious inferences l'eem to have never occurred to 
M. iiellant. Even the unexpected defeent of his thermome- 
ter on being expofed to heat, ftrange and inexplicable as it muft 
have appeared, and contradictory to all the notions he enter- 
tained, did not fuggeft to him a doubt of the inftrument’s 
marking the real temperature of the air. But we now r know 
that it ceafed to do lo after the cold had increafed a few degrees 
below - 39 0 ; that all the unufual phenomena turned upon the 
congelation of the quicklilver ; and that the feverity of this 
feafon, though greater than ulual in Lapland, did not exceed 
that of common winters by any luch remarkable difference. 
The vacuum or hollow bubble, obierved after the quicklilver had 
fallen back into the ball, ffiew r s how very much it had contracted 
by the congelation. This bubble moved upon inclining the 
D d d 2 thermo- 
