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more important subject than it seems to a careless observer. It affects 
navigation, and through that the whole transportation system of the 
country. A river which is navigable only at high water, orfor a part of 
the season, is of little value as a channel of commerce, and can scarcely 
be considered an active competitor with such an agency as the railroad. 
And yet to such acondition are many of our great streams being brought, 
and we are now called upon to spend large sums of money, on the one 
hand in dredging and cutting in order to utilize a decreasing amount of 
water in the dry season, and, on the other, in building dykes and em- 
bankments against ever-increasing floods from the melting snows of 
spring-time or as the effect of protracted rains. 
The character of the streams has an important if not a controlling in- 
fluence upon our manufactures. <A system of factories and mills, which 
would spring up spontaneously along a water-course regularly and 
equally supplied with water, is rendered impossible if this stream be- 
comes a mountain torrent during one quarter of the year, and an all but 
dry bed during another, even if in the two cases the same quantity 
of water falls during the year and flows off through this channel in the 
course of atwelvemonth. Such a state of things necessitates a resort to 
more expensive means of water supply, or to auxiliary power of another 
kind, which again means increased cost of production and a rise in the 
cost of living for every member of society. ° 
Irregularity of streams also affects agriculture, aud not only indi- 
rectly, through the industries above-mentioned, but direetly as well. 
The decreased volume of water during the period when the least rain 
falls diminishes the humidity of the atmosphere and affects powerfully 
the quality and variety of crops which may be raised, while the in- 
creased volume at high water cuts into and carries away enormous 
quantities of the soil from the farms lying along the banks of the 
streams, even when it does not by its overflow spread ruin and devas- 
tation through the adjacent valleys. 
A striking illustration of the extent to which a stream may be 
changed by the deforesting of its headwaters and shores is afforded 
by the river Schuylkill, from which Philadelphia draws its water 
supply. The current has become for a large part of the year so shal- 
low and sluggish that it is no longer able to rid itself, as it once did with 
ease, of the impurities which are poured into it, and the quality of the 
water is deteriorating at a more rapid rate than the stream of impurity 
is increasing. This result can be due only to a change in the character 
of the stream itself. | 
The fundamental importance of forests is, if possible, still more evi- 
dent in mountainous and hilly districts. Their existence in such situa- 
tions is the absolutely essential condition, we will not say of obtaining the 
necessary rain-fall, or preserving the necessary moisture, but even of 
maintaining the soil itself. Without forests a soil can not be made, or 
preserved, on our mountain-sides. The action of frost and of rain 

