LIMITS OF HUMAN POWER. 
45 
raising the level of morasses which their own overflows had 
created; ground submerged by the encroachments of the 
ocean, or exposed to be covered by its tides, has been rescued 
from its dominion by diking; * swamps and even lakes have 
been drained, and their beds brought 'within the domain of 
agricultural industry ; drifting coast dunes have been checked 
and made productive by plantation ; seas and inland waters 
have been repeopled with fish, and even the sands of the 
Sahara have been fertilized by artesian fountains. These 
achievements are more glorious than the proudest triumphs of 
war, but, thus far, they give but faint hope that we shall yet 
make full atonement for our spendthrift waste of the bounties 
of nature. 
It is, on the one hand, rash and unphilosophical to attempt 
to set limits to the ultimate power of man over inorganic 
nature, and it is unprofitable, on the other, to speculate on 
what may be accomplished by the discovery of now unknown 
and unimagined natural forces, or even by the invention of 
new arts and new processes. But since we have seen aerosta¬ 
tion, the motive power of elastic vapors, the wonders of 
modern telegraphy, the destructive explosiveness of gun¬ 
powder, and even of a substance so harmless, unresisting, and 
inert as cotton, nothing in the way of mechanical achievement 
seems impossible, and it is hard to restrain the imagination 
from wandering forward a couple of generations to an epoch 
when our descendants shall have advanced as far beyond us in 
physical conquest, as w r e have marched beyond the trophies 
erected by our grandfathers. 
I must therefore be understood to mean only, that no 
agencies now known to man and directed by him seem 
adequate to the reducing of great Alpine precipices to such 
* The dependence of man upon the aid of spontaneous nature, in his 
most arduous material works, is curiously illustrated by the fact that one 
of the most serious difficulties to be encountered in executing the proposed 
gigantic scheme of draining the Zuiderzee in Holland, is that of procuring 
brushwood for the fascines to be employed in the embankments. See 
Diggelen’s pamphlet, u Groote WerJcen in Nederland.'" 
