the Congelation of ickjVver . \ 
to 96° below o *. The fame appearance of air bubbles which 
he had fo frequently remarked in fuch great defcents of the 
thermometer, puts it beyond doubt that the quickfilver was 
frozen. This event furnifhed a very ftriking proof of the force 
of habit in reconciling men to hardfhips, which in their com- 
mon ccurfe of life are thought intolerable. Profeflor gmelin, 
who had now been nine years in Siberia, not only bore to travel 
in this exceflive cold, but alfo, in order to afcertain the height 
of the mountains he traverfed, employed himfelf in obferving 
a barometer, whilft the quickfilver was freezing in his inftru- 
ments. 
Tliefe are the principal of Dr. gmelin’s thermometrical ob- 
fervatibns* He collected many more, part of which were de- 
ffroyed by fire or other accidents, and the remainder feem to 
contain no further information. They were confidered by him 
as demonftrating the cold of Siberia to exceed that even of the 
moft northern parts of Europe near 100 degrees, an opinion 
which lias fmce been almoft univerfally adopted ; whereas we 
have, in faff, no proof that the difference of climate amounts, 
to fo much as the variation between one winter and another. 
At Yenifeifk, where the cold was fointenfe in 1735, it does not 
feem to have ever been fufficient to freeze a thermometer in the 
winter that M. gmelin fpent there four years afterwards ; and 
It will loon be (hewn that quickfilver has congealed more than 
once in Europe. All that we are authoriled to conclude, there- 
fore, with refpecl to the Siberian climate, is, that the cold 
there not unfrequently exceeds the degree indicated by - 39 0 of 
a ffandard mercurial thermometer. 
* Reife. Theil. IV. p. 512 — 515. 
