IRRIGA TIOiV. 3 1 1 



question had less rain-fall than six inches per month, and the 

 average of these twenty-one months was about 3.02 inches per 

 month, or only about half of what was needed. Some of the 

 protracted seasons of drought were almost entirely rainless for 

 six weeks, during which the weather was excessively hot and 

 windy, and vegetation suffered extremely in consequence." 



Mr. Philbrick estimates that 27,000 gallons, or 108 tons, 

 of water are needed per acre at each watering, which, in a 

 dry period, should be repeated ev.ry five days. This enor- 

 mous quantity leads him to suggest that — 



"before embarking in an enterprise of irrigation, it would be 

 best to make sure that the source can be depended upon for a 

 sufficient supply of water in the driest seasons ; for it is pre- 

 cisely at such times that the most water is needed. Ordinary 

 springs and wells, therefore, are entirely inadequate to furnish 

 water for anything more than a small patch or garden. The 

 only sources to be depended upon for large areas are unfailing 

 streams, lakes, and ponds. There are few gardens so favorably 

 situated that the water can be drawn from canals and ditches 

 directly from some pond or stream. When this can be done it 

 is by far the cheapest method ; and it is in this way that the 

 extensive irrigating works of Lombardy, Spain, France, Califor- 

 nia, and Colorado are constructed. Where this system is 

 adopted, considerable expense is required to grade the land into 

 inclined beds, so as to distribute the water easily and evenly ; 

 but, once done, the water is applied at a very trifling cost — so 

 cheaply that it is used for farm crops in Lombardy and the 

 South of France." 



In most instances, however, our land is so located that we 

 cannot irrigate it by a natural flow and fall of water. In 

 this case, it may be distributed by water-carts and by hand. 

 This can be done only on a very small scale. The cost in 

 time and labor would be much too great for profitable re- 

 turns, and the ground would be so beaten and trampled as 



