the Congelation of Quick fiver, 
likewife to one made of fpirits, whofe relative movement has 
been aicertained by comparifon. This inftrument, while the 
otheis were three, four, or almoft five hundred degrees below 
o, never funk further than to a point which correfpond's with 
- 46° of a ftandard mercurial thermometer. Hence it would 
have been eafy to infer, both that the quickfilver actually con- 
gealed on thefe occalions, and that the degree of cold neceff ary 
tor fuch an effect does not exceed — 46°. That the moftintenfe 
cold of Hudfon’s Bay, during a feries of feveral years, went 
fo little below the point of mercurial congelation, well de- 
lerves to be noticed ; and as it feems to be feldom greater in 
Siberia, at leaft in the parts vifited by gmelin or pallas, the 
eftedbs being not more violent, perhaps we are authorifed to 
conclude, that the extreme of artificial cold, produced by 
fnovv and nitrous acid, correlponds pretty exactly with the ex- 
treme of natural cold in the molt rigorous climates which can 
well be inhabited. 
Mr. Hutchins’s meteorological journal at Hudfon’s Bay 
confirms what he mentions in the remarks on his third experi- 
ment, that in the coldeft weather the wind is to the fouthward 
of W. which muff evidently depend on fome local circumftance 
of that country. During my own refidence in America, I 
thought I could diftinftly perceive that the coldeft winds, vul- 
garly called nortk-wefers , did not blow exactly from that quar- 
ter ; but at Rhode Ifland, for inffance, came from N.W. by 
W. or a point frill more to the weft ward ; at New York were 
rather nearer the W. than the N. ; and at Philadelphia almoft 
due N.W. On tracing lines in thefe directions from Albany 
Fort, Rhode Ifland, and Philadelphia, they are found to meet 
among the great ridges of mountains which feparate Hudfon’s 
Bay from Lake Superior ; whence a fufpicion arifes, that thefe 
mountains 
