27 



more important subject than it seems to a careless observer. It affects 

 navigation, and tbrougli tbat the wbole transportation system of the 

 country. A river which is navigable only at high water, or for 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 a twelvemonth. Such a state of things necessitates a report 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, and not only indi- 

 rectly, through the industries above-mentioned, but directly 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 w^ater 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 w^ater 

 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, wewillnotsay 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 raiu 



