73

68.

are consequently divested of a smaller quantity
of their intense rigour; and afterwards sweeping
across, the immense chain of mountains covered
with perpetual snow and ice that intersects the
whole of these cheerless regions, they acquire a penetrating
severity by traversing so vast a track of
frozen ground that even their progress into a
lower latitude cannot disarm them of.

Of these winds the North West is the most vigorous
and even in summer as soon as it prevails
the transition from heat to cold is so sudden,
the thermometer has been known to fall nearly
thirty degrees in a very few hours. The highest
range of the summer heat is usually between 90
and 102 degrees of Fahrenheit, but an atmosphere
always particularly pure abates the oppressive
fervour felt in other parts at the same point.