INFLUENCE OF CLIMATE ON PLANTS. 
183 
owing to the former of these causes, (lack of light and heat,) the escape of 
water is, in cold, wet weather, much impeded, and stagnates about the roots of 
plants, to their great detriment. 
Valleys, to be perfectly adapted for growing exotic plants, must not be circum- 
scribed, especially if traversed by a river or stream. No spot can be less fitted for 
conducting the more refined part of floriculture, than a narrow valley, through 
which a river flows. The constant exhalations from water are calculated not only 
to saturate the leaves and branches of plants, but, by remaining in the lower 
stratum of the atmosphere during a frosty night, in many instances occasion all the 
consequent destruction. All who have had an opportunity of observing the injury 
sustained by plants in dales from a slight hoar-frost, must have noticed that in those 
districts which were above the low-lying vapours, similar plants have wholly escaped 
its effects. This simple circumstance casts much valuable light on the subject of 
the present article. 
Wherever water exists, it has a constant tendency to lower the temperature ; 
and the vicinities of places wherein it abounds most, suffer the greatest reduction of 
heat. The sea may, however, be considered an exception to this, since its immense 
and continuous expanse of water retains through the winter a higher temperature 
than the superincumbent and surrounding air. Plants growing within a few miles 
of the sea coast, (at least of that portion of it which is not swept by the icy blasts 
from colder regions,) may therefore be presumed to enjoy an increased degree of 
heat at that season, on account of the incessant radiation from so large a body. On 
the other hand, by absorbing more rapidly than land the superior heat of the 
atmosphere, it materially reduces the temperature in summer, and thus maintains 
a comparative equability. 
With rivers and all smaller channels of water, it is wholly different. The 
mists which are perpetually arising from them, if confined between two ranges of 
hills, having no room to disperse, are condensed and precipitated to the earth in 
cold evenings, and, by their deposition upon plants, affording as it were an attrac- 
tion to frost, subside into globules of congealed fluid, the mischief occasioned 
by which is soon exhibited after the first action of the sun. But where the valley 
occupies a broad district, these vapours, possessing like heat a diffusive power, are 
dispersed throughout even its most remote parts, and their density, with its con- 
current effect upon vegetation, is proportionately lessened. 
Having stated thus cursorily the changes in the temperature of a climate which 
the altitude of a spot or its proximity to water will produce, we will now, lest 
any misapprehension should arise, add our own deductions and conclusions. All 
low marshy places should be particularly avoided, as containing within themselves 
elements which, if not counteracted, inevitably cause or lay the foundation of disease 
and death. We here include those tracts in which any disposition (although only 
periodical) to particular dampness is apparent. Whatever may be the impressions 
or desires of cultivators, nothing is more certain than that the production of a 
