230 INFLUENCE OF THE FOREST ON SPRINGS. 
Of the converse proposition, namely, that the planting of 
new forests gives rise to new springs and restores the regular 
flow of rivers, I find less of positive proof, however probable it 
may be that such effects would follow.* A reason for the 
want of evidence on the subject may be, that, under ordinary 
circumstances, the process of conversion of bare ground to soil 
with a well-wooded surface is so gradual and slow, and the 
time required for a fair experiment is consequently so long, 
that many changes produced by the action of the new geo- 
graphical element escape the notice and the memory of ordi- 
So remarkable a change could not have escaped the notice of Humphreys 
and Abbot, whose most able labors comprise the years 1850-1861, had it 
occurred during that period or at any former time within the knowledge of 
the many observers they consulted; but no such fact is noticed in their ex- 
haustive report. However, even if an increase in the volume of the Mississippi, 
for a period of ten or twenty years, were certain, it would still be premature to 
consider this increase as normal and constant, since it might very well be 
produced by causes yet unknown and analogous to those which influence the 
mysterious advance and retreat of those Alpine ice-rivers, the glaciers, Among 
such causes we may suppose a long series of rainy seasons in regions where 
important tributaries have their far-off and almost unknown sources; and 
with no less probability, we may conceive of the opening of communications 
with great subterranean reservoirs, which may from year to year empty large 
quantities of water into the bed of the stream ; or the closing up of orifices 
through which a considerable portion of the water of the river once made its 
way for the supply of such reservoirs.—See upon this point, Chap. IV., Of 
Subterranean Waters ; post. 
* According to the Report of the Department of Agriculture for February, 
1872, it is thought in the Far West that the young plantations have already 
influenced the water-courses in that region, and it is alleged that ancient 
river-beds, never known to contain water since the settlement of the country, 
have begun to flow since these plantations were commenced. See also Hay- 
DEN, Report on Geological Survey of Wyoming, 1870, p. 104, and Bryant, 
Forest Trees, 1871, chap. iv. 
In the Voyage autour du Monde of the Comte de Beauvoir, chap. x., this 
passage occurs: Dr. Miiller, Director of the Botanic Garden at Melbourne, 
‘‘has distributed through the interior of Australia millions of seedling trees 
from his nurseries. Small rivulets are soon formed under the young wood; 
the results are superb, and the observation of every successive year confirms 
them. On bare soils he has created, at more than a hundred points, forests 
and water-courses.”’ 
