the Congelation of Quickfilver, 367 
ref ponding with - 35° of Fahrenheit’s fcale. This eftima- 
tion, though now found to be many degrees lefsthan the truth, 
yet approaches it fo near as to imprefs a very favourable idea 
both of M. DE l’isle’s talent for obfervation, and of his fupe- 
riority to vulgar prejudices. It is to this fame gentleman that 
we are indebted for an account of the aflonilhing leveritv of 
the climate in the north -eaffernmofl extremities of Aha. Ya- 
kutlk itfelf, lying further in that direction than any other place 
where M. gmelin redded, evidently partakes of the fame rigo- 
rous cold, if a winter in which quicklilver froze feveral times 
was efteemed unufually mild by the inhabitants. 
Another let of oblervations, in the courfe of which the 
mercury frequently congealed, were made by Profeflor gmelin 
at Kirenga Fort, lat. 57$ N. long. 108 E. in the winter of 
1737 and 1738. His thermometer on different days flood at 
- 108 0 , -86°, - ioo°, —ii 3 0 , and feveral intermediate de- 
grees. Some extraordinary appearances, which very much, per- 
plexed him in thele oblervations, not only admit of a ready 
Iblution from Mr. hutchins’s determination of the freezing- 
point of quicklilver, but alfo confirm it with wonderful pre- 
cilion. • . 
• *-*».*■ [ 
On the 27th of November (O. S.) after the thermometer 
had been Handing two days at - 46°, the profeflor found it 
funk at noon to 108 0 . He adds * : “I had fcarcejy noted down 
44 this obfervation, when fufpe&ing iome miflake, I ran back 
44 and examined it again. I law the quicklilver now at 102*% 
44 and it continued riling fo faff, that in the fpace of. half an 
44 hour it had reached to - 19 0 .” The explanation of this phae- , 
nomenon, which appeared lo odd to M. gmelin, is very evi- 
dent. When the intenfe cold fet in, the quickfilver froze in 
* Reife. Theil. II. p. 619. * . 
Vol. LXXIII. C c c his 
