GEOLOGICAL INFLUENCES—INFLUENCE OF HUMAN ACTION. 13 
knowledge of special details which only years of application 
can master. It may be profitably pursued by all; and every 
traveller, every lover of rural scenery, every agriculturist, who 
will wisely use the gift of sight, may add valuable contribu¬ 
tions to the common stock of knowledge on a subject which, 
as I hope to convince my readers, though long neglected, and 
now inartificially presented, is not only a very important, but 
a very interesting field of inquiry. 
Cosmical and Geological Influences. 
The revolutions of the seasons, with their alternations of 
temperature, and of length of day and night, the climates of 
different zones, and the general condition and movements of 
the atmosphere and the seas, depend upon causes for the most 
part cosmical, and, of course, wholly beyond our control. The 
elevation, configuration, and composition of the great masses 
of terrestrial surface, and the relative extent and distribution 
of land and water, are determined by geological influences 
equally remote from our jurisdiction. It would hence seem 
that the physical adaptation of different portions of the earth 
to the use and enj oyment of man is a matter so strictly belong¬ 
ing to mightier than human powers, that we can only accept 
geographical nature as we find her, and be content with such 
soils and such skies as she spontaneously offers. 
Geographical Influence of Man. 
But it is certain that man has done much to mould the 
form of the earth’s surface, though we cannot always distin¬ 
guish between the results of his action and the effects of 
purely geological causes; that the destruction of the forests, 
the drainage of lakes and marshes, and the operations of rural 
husbandry and industrial art have tended to produce great 
changes in the liygrometric, thermometric, electric, and chem¬ 
ical condition of the atmosphere, though we are not yet able to 
measure the force of the different elements of disturbance, or 
