546 



SCIENCE 



[N. S. Vol. XXVIII. No. 721 



tion increases the richest lands are rapidly 

 absorbed, those of second and third grade 

 must then be used and in the end all the 

 fertile soil of the country is under cultiva- 

 tion. After this, if population is to grow, 

 more scientific methods of agriculture must 

 be adopted or the hitherto useless land 

 must be converted into fertile areas. The 

 useless land consists of mountainous, desert 

 and swampy regions. As a rule, the moun- 

 tainous districts are not available for agri- 

 culture, though they may be for forestry. 

 The desert land can in many cases be re- 

 claimed by irrigation and the swampy land 

 may often be reclaimed by drainage. Both 

 of these processes, irrigation and drainage, 

 are essentially within the province of the 

 engineer and it is due to his efforts that so 

 much fertile soil has been added to our 

 national domain. Eight million acres have 

 already been irrigated and in the next 

 twenty-five years it is estimated that twelve 

 million acres more may be reclaimed. "We 

 have in the United States eighty million 

 acres of swampy land, of which twelve mil- 

 lion have already been drained and twenty 

 million more may be drained in the future. 

 This will enable us to raise a food supply 

 for many millions of people and hence 

 population can grow to this extent. But 

 the problem of reclamation is only a part 

 of the greater problem of the food supply 

 of the nation and this does not belong to 

 the engineer. 



INLAND V^ATERWAYS 



The forests, water power, irrigation and 

 inland navigation are more or less con- 

 nected. The cutting away of the forests 

 has been the cause of severe floods during 

 certain sections of the year and very low 

 water in the streams during the rest of the 

 year. This has been detrimental to navi- 

 gation and to the successful use of water 

 power. Some streams are available, both 

 for irrigation and water power and it is a 



question which of these is of the greatest 

 value. If the water in a stream is used for 

 irrigation it can not be used for water 

 power and hence only one of these methods 

 of utilization is available. Some streams 

 can be used for power and also for navi- 

 gation. The water which is used for power 

 is not destroyed, but is turned back into the 

 stream after its energy of motion or posi- 

 tion has been used. The dams and other 

 works necessary for the utilization of power 

 form an impediment to navigation, but can 

 be overcome by canals. Thus it seems that 

 the question of the use of water must be 

 studied from several standpoints and the 

 final solution of the problem will depend 

 upon a number of difi'erent facts. 



The United States possesses an unrivaled 

 natural system of waterways. Professor 

 Johnson says that at present we have 25,- 

 000 miles of navigable streams and there 

 is as much more that can be made navi- 

 gable. There are 1,410 miles of navigable 

 waters in the Great Lakes and we have 2,120 

 miles of canals. There are 2,500 miles of 

 waterways in sounds, bays and bayous on 

 the Atlantic and Gulf coasts. These can 

 all be made into a splendid inland system 

 by the construction of a comparatively few 

 miles of canals. On account of the absence 

 of these canals only a very small part of 

 this natural water route is at present util- 

 ized. In view of the importance of our 

 waterways very little has so far been done. 

 We have wasted our natural routes of 

 travel by the destruction of forests, by al- 

 lowing our streams to fill up with sand, and 

 by our neglect to use those which are still 

 available. It is much cheaper to transport 

 heavy material by water than by rail and 

 the great advantage which comes from the 

 proper use of waterways is shown wherever 

 the government has given the necessary aid. 

 The most striking evidence of the value of 

 work properly directed is seen in the Great 

 Lakes, where a hundred million dollars has 



