REACTION OF MAN ON NATURE. 9 
many geographers, and treated with much fulness of detail in 
regard to certain limited fields of human effort and to certain 
specific effects of human action, it has not, as a whole, so far 
as | know, been made matter of special observation, or of his- 
torical research, by any scientific inquirer. Indeed, until the 
influence of geographical conditions upon human life was 
recognized as a distinct branch of* philosophical investigation, 
there was no motive for the pursuit of such speculations; and 
it was desirable to inquire how far we have, or can, become 
the architects of our own abiding place, only when it was 
known how the mode of our physical, moral, and intellectual 
being is affected by the character of the home which Provi- 
dence has appointed, and we have fashioned, for our material 
habitation.* 
It is still too early to attempt scientific method in discussing 
this problem, nor is our present store of the necessary facts by 
any means complete enough to warrant me in promising any 
approach to fulness of statement respecting them. Systematic 
observation in relation to this subject has hardly yet begun, 
and the scattered data which have chanced to be recorded have 
never been collected. It has now no place in the general 
scheme of physical science, and is matter of suggestion and 
speculation only, not of established and positive conclusion. 
At present, then, all that I can hope isto excite an interest in 
a topic of much economical importance, by pointing ont the 
directions and illustrating the modes in which human action 
has been, or may be, most injurious or most beneficial in its 
influence upon the physical conditions of the earth we inhabit. 
We cannot always distinguish between the results of man’s 
action and the effects of purely geological or cosmical causes. 
The destruction of the forests, the drainage of lakes and marsh- 
es, and the operations of rural husbandry and industrial art have 
* Gods Almagt wenkte van den troon, 
En schiep elk volk een land ter woon : 
Hier vestte Zij een grondgebied, 
Dat Zij ons zelyen scheppen liet, 
