44 



FORESTRY AND IRRIGATION. 



January, 1902, 



several acres. The possibility of irri- 

 gation in this way is limited largely by 

 the depth to the water in the well and 

 the number of animals available. 



The next step is the use of the ordi- 

 nary threshing engine, replacing the 

 horse and driving a pump as shown in 

 the accompanying sketch. Tracts of 

 considerable size have been watered in 

 this way, and the value of the crops 

 greatly increased. For example, onions, 

 which would have been almost worth- 

 less, owdng to a drouth, have as the 

 result of water properl}^ applied sold at 

 $150 per acre, and celery at $200 per 

 acre, repaying in a season the whole 

 outlay for well, pump, and engine. 

 Special forms of pumps driven by steam, 

 gasolene, and other forms of engine 

 have been devised suited to the needs 

 of the irrigator. 



The most important source of power 

 for pumping is the wind. On the broad 

 valleys and plains of the arid regions 

 the wind movement is almost continu- 

 ous for days and weeks, carrying away 

 the dry leaves, even at times sweeping 

 up the loo.se soil. In many localities 

 there are at depths of 20 or 50 feet or 

 more beneath the surface, pervious beds 

 of sand or gravel filled with waters by 

 the infiltration of rainfall or by percola- 

 tion from stream channels. 



It is a comparatively simple and in- 



expensive operation to sink a well into 

 this water and erect a windmill, attach- 

 ing this to a suitable pump. The ma- 

 chinery once provided is operated da)' 

 and night by the ever-present wind, 

 bringing to the surface a small, but con- 

 tinuous supply of water. This small 

 stream, if turned out on the soil, would 

 flow a short distance, then disappear 

 into the thirsty ground, so that irriga- 

 tion directly from a windmill is usually 

 impracticable. 



To overcome this difficult3^ it has 

 been found necessary to provide small 

 storage reservoirs or tanks built of earth, 

 wood, or iron to hold the water until it 

 has accumulated to a volume sufficient 

 to permit of a stream of considerable size 

 being taken out for irrigation. Such a 

 stream flowing rapidly over the surface 

 will penetrate to a distance and cover an 

 area which would seem impossible with 

 the small flow delivered by the pump. 



The windmills employed in irrigation 

 are of all kinds, from the highest t3'pe 

 of the machinist's art down to the crude 

 home-made devices. These latter are 

 not to be despised, as many of them are 

 highly effective, and at least they have 

 enabled settlers to procure a small 

 amount of water and to obtain a foot- 

 hold upon the soil, by which ultimately 

 they may be able to obtain funds to 

 procure better implements. 



PUMPING WATER WITH A THRESHING ENGINE. 



