19 
45 Atmosphere, influenced by Land and Water. Many cir- 
cumstances, besides the immediate agency, or absence, of the 
solar rays, combine to influence the temperature of tlie atmos- 
phere. Both the earth and sea are continually softening the 
rigours of winter, by imparting portions of the heat they im- 
bibed, during summer; whilst that absorption of summer heat, 
and also evaporation, ameliorate the intensity of the vivid sun- 
beams at that season. The capacities of land and water for 
receiving and communicating heat, are, however, very different; 
and the capacity of each element is also variable under difl'erent 
circumstances — water from its depth; earth from its quality, 
colour, or surface position. During summer, a maritime at- 
mosphere is cooler than an inland one, partly by the process 
of evaporation, and partly by the diffusion of the solar heat to 
a greater depth; but in winter, it is warmer than over the land, 
from the surface water giving out its heat, and then descending 
by its augmented gravity, when its place becomes occupied by 
water of a higher temperature, to yield up its heat, in turn, and 
also its situation. This alternate change of heavier and lighter 
particles proceeds, and the temperature of the atmosphere is 
thereby continually equalized in a greater degree than by land, 
from the more ready facility water affords to the diffusion of 
its heat; and also the depth easily acted upon. Hence it is, 
that in gardens on the sea coast, even in Scotland, plants thrive 
in the open air, in winter, which, in the midland counties of 
England, would perish from the severity of cold. 
46 Atmosphere, influenced by Forests and Position. In 
latitudes, distant from the equator, islands are w armer than con- 
tinents, because they jiarticipate more of the temperature of the 
sea. This is, happily for us, elucidated by the temperature of 
our own island; Great Britain being under the same parallel 
of latitude as the inclement Labrador, and countries south of 
Hudson’s Bay, — too cold even to admit of cultivation. Coun- 
tries that lie southward of any sea, are warmer than those that 
have the same sea to the south of them, at least, in our hemis- 
phere; because, the winds that should cool them in winter, are 
tempered, by passing to them over that sea. Tracts of land, 
which are covered with trees and luxuriant vegetables, are much 
colder than those which have less surface of vegetable matter: 
for though living vegetables alter their temperature slowly, yet 
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