C 2 5 8 ] 
The Air of Sibiria , with refped to its Gravity, is, 
as in other Countries, the nearer the Sea the heavier; 
and the more remote, the lighter: So that at Ki * 
achta fcarcc one Perfon in our Author's Retinue 
efcaped without home Indifpofition: They were feized 
after their Arrival, fomc with acute Fevers, others 
complain’d of extreme Latitude and Deje&ion. It 
was in the Spring- Scafon, the Weather moderate, 
their Manner of living regular, nor had they been 
much fatigu’d with their Journey ; in Ihorr, they 
could attribute it to no other Caufe than the Light- 
nefs of the Air. 
In thefe Provinces, viz. beyond the Lake Raical , 
our Author tells us, that Intermittents are feldom 
heard of, and Ophthalmies are endemic : But that, 
in the fenny Trails which lie near the Oby and 
Jenifea , intermitting Fevers are very frequent. 
The Coldnefs of the Air of Sibiria is of all others 
the moft remarkable Quality. In fome Places it 
Blows frequently in September-, and not feldom in 
May : In jacutsk , if the Corn is not ready to cut 
in Auguft , which often is the Cafe, the Snow fome- 
times prevents it, (and buries the Harveftall together. 
At Jacutsk the Profeflor order’d a Hole to be dug 
in the Earth, in a high open Place, on the 1 8th of 
June i the Mold was n Inches deep; below that 
was Sand about z\ Feet,- it then began to feel hard, 
and in half a Foot more it was froze as hard as 
poflible. 
of Mont Blanc , meafured partly by the Barometer, and where 
inaccefiible from the Snow that covers it, by trigonometrical Ope- 
rations, is 12459 Feet, or fomewhat more than 2c>76Toife$ above 
the Level of the Rhone ; which, added to the Height of this above 
the Sea, makes 13115 French Feet, or about two Englijh Miles 
and two Thirds. 
