2i2 THE POPULAR SCIENCE MONTHLY 



methods of sewage disposal. No treachery to the land can be so great 

 as that which sends out into the sea the highly concentrated nitrogenous 

 products which have with toil been wrung from a soil which is becoming 

 poor in capacity for crops. In this primitive riddance of valuable 

 matter we accomplish a further loss by polluting the waters and if we 

 do not thus endanger human life, we destroy the fields in which a 

 certain important amount of aquatic food can be produced. 



A further gain can be had on soils already in use by expert manage- 

 ment in the direction of proper succession of crops and a thoroughness 

 of occupation and tillage often seen in Italy, France or Belgium, but 

 only exceptionally found as yet in our own land. We need not only 

 better directed labor, but more labor on the same soil. In the regions 

 of sufficient rainfall, which comprise nearly the eastern half of the 

 United States, we shall find, or did find in 1900, seven men per average 

 square mile, tilling the soil, or one to each lot of 91.4 acres. Making 

 generous allowance for ground not in tillage, we still find the working 

 force far too small to bring maximum quantities of food out of the 

 ground. We need also on much plow land and meadow east of the 

 arid belt supplementary irrigation for many seasons and for some crops, 

 and with abundant water resources, there is no good reason why nature 

 should not thus be helped to her best. Some areas, many, it would 

 doubtless be better to say, would be doubled in productive worth by 

 more effective drainage than has yet been applied. The barest inspec- 

 tion of crop averages per acre, or of half the ripening harvests that fall 

 under the eye of the traveler, supports the belief that a vast increment 

 of food can be won from lands that are not now given a full chance. 



Further inquiry leads us to lands not now cultivated, which might 

 and will be made productive. Here some of our largest reserves appear. 

 Lands of an arid or semi-arid character embrace about two fifths of our 

 territory. In these great fields, and in small patches now improved, 

 crops can not be expected unless water is applied by man. There is 

 doubtless force in the claim that these soils are potentially marked by 

 exceptional richness, due not only to the fact that they are virgin soils 

 as related to man, but because they have not suffered the leaching and 

 waste of important elements which have affected soils in lands of large 

 rainfall. It is cited by Hilgard that Nile lands have for centuries 

 supported an average population of more than one and one half persons 

 per square acre, which means a density of about 1,000 per square mile. 

 Without questioning the accuracy of this claim, it may be urged that 

 we do not know whether flooding by the Cordilleran irrigator would be 

 as favorable to fertility as the flooding of the Nile. Nor may we forget 

 comparative standards of living any more than in the case of China. 



We must also keep in sight the inevitable condition that there is 

 water enough in the west to make fertile but a small fraction of the dry 

 area. If we accept this at one fifteenth and receive without discount 



