UNCLE SAM'S BIG FARM 327 



ble drainable land yet undrained 79,000,000 acres. 

 The arid area not possible of irrigation by reason of the 

 lack of water, but some of which may be devoted to dry- 

 farming, is 127,000,000 acres; forest lands totally un- 

 suitable for agriculture, 460,000,000 acres ; forest lands 

 suitable for grazing, 467,000,000 acres; and desert 

 land of which there is no hope for any purpose, 40,- 

 000,000 acres. These subdivisions of the different 

 kinds of land are summarized in following tables: 



From the estimate of 935,000,000 acres of arable land 

 there should probably be deducted: 

 Land in roads, 12 acres for every section 



(640 acres) of arable land, or about 17,700,000 acres. 



Land in farmsteads, possibly 2 acres for each 



of the 6,361,000 farms, or about 12,700,000 " 



30,400,000 " 



The loss of arable land because of fences 

 would probably equal the loss from roads, 

 Leaving a total arable area of 900,000,000 acres, or less. 



Acres. 



1. Area of irrigated land in United States, 1910 

 (census) 13,738,485 



2. Approximate area irrigated at present 15,500,000 



3. Estimated area of irrigated land when all 

 available water is used and transported by 

 present methods, less necessary deduction for 

 drainage, proportionate acreage of different 



crops remaining as at present 50,000,000 



4. Estimated area of irrigated land when all avail- 

 able water is transported with minimum waste 

 without regard to cost of construction of con- 

 duits, less necessary deduction for drainage, 

 proportionate acreage of different crops re- 

 maining as at present 65,000,000 



5. Estimated area of irrigated land with most 

 perfect known transmission of water and opti- 



