The Bulletin. 53 



and form great avenues of commerce; the forests which yield the materials 

 for our homes, prevent erosion of the soil, and conserve the navigation and 

 other uses of the streams; and the minerals which form the basis of our 

 industrial life, and supply us with heat, light and power. 



"We agree that the land should be so used that erosion and soil wash shall 

 cease ; and that there should be reclamation of arid and semiarid regions by 

 means of irrigation, and of swamp and overflowed regions by means of drain- 

 age ; that the waters should be so conserved and used as to promote navigation, 

 to enable the arid regions to be reclaimed by irrigation, and to develop power 

 in the interests of the people ; that the forests which regulate our rivers, sup- 

 port our industries, and promote the fertility and productiveness of the soil 

 should be preserved and perpetuated; that the minerals found so abundantly 

 beneath the surface should be so used as to prolong their utility; that the 

 beauty, healthfulness, and habitability of our country should be preserved 

 and increased ; that sources of national wealth exist for the benefit of the 

 people and that monopoly thereof should not be tolerated." 



"It may at first seem strange that man, who prides himself on being the 

 highest type in the animal kingdom, as well as the only animal endowed with 

 reasoning powers, should prove the most destructive; yet such is the case. 

 Through prodigality, due in part to thoughtlessness, and in part to a willful 

 disregard for any but immediate interests, man has, apparently from the very 

 beginning of his existence, so conducted himself with regard to natural re- 

 sources as to leave little less than ruin in his path. This is true, not merely 

 with reference to his treatment of the soil, but of the deeper lying rocks 

 and their mineral contents. In the name of development he has squandered; 

 through careless husbandry, he has not merely impoverished the soil, but in 

 many cases allowed it to run waste and be lost beyond recovery." 



The Mississippi River gives the Gulf of Mexico each year 7,468,694,400 

 cubic feet of soil. This would cover a square mile 268 feet deep and repre- 

 sents the removal of 3 inches, mostly of surface, from 1,072 square miles or 

 685,080 acres, which, if capable of producing one-half bale of cotton, repre- 

 sents the loss of 342,540 bales, or, at $50 a bale, $17,127,000 annually ; and it 

 is probable that the gullying now going on in other than the Mississippi's tribu- 

 taries between the Mississippi and the Potomac is equally as great as that being 

 accomplished by the Mississippi. Further, these figures represent the removal 

 of soil from the land and into the sea and do not take into consideration the 

 thousands greater quantities annually moved, but not carried to the sea. 



Moving water gives us one of our greatest natural forces. Its power for 

 work is exceedingly great and, if not controlled, excessively destructive. 



A better understanding of this force may lead to a better understanding of 

 the causes of gullying and its checks. 



"If the surface of the obstacle is constant, the force of running water varies 

 as the velocity is squared. This may be easily proved. Suppose we have an 

 obstacle, like the pier of a bridge, standing in water running with any given 

 velocity. Now, if for any cause the velocity of the current be doubled, since 

 momentum or force is equal to quantity of matter multiplied by velocity, the 

 force of the current will be quadrupled, for there will be double the quantity 

 of water striking the pier in a given time with double the velocity." "The 

 transporting power of a current or the weight of the largest fragment it can 

 carry varies as the sixth power of the velocity. This seems so extraordinary 

 a result that, before accepting it, we will try to make it still more clear by an 

 example. Let a represent a cubic inch of stone which a current of a certain 

 velocity will just move. Now the proposition is that, if the velocity of the 

 current is doubled it will move the stone b, sixty-four times as large. That 

 it will do so is evident from the fact that the opposing surface of b is sixteen 

 times as great as that of a and the moving force would be increased sixteen 

 times from this cause. But the velocity being doubled, as we have already 

 seen, the force against every square inch of b will now be four times that 

 previously against c, and therefore the whole force from these two causes 

 would be 16X4=64 times as great. But the weigbt is also sixty-four times 

 as great; therefore the current will just be able to move it We may accept 



