144 Irrigation. 



a hundred feet asunder, and should have a hydrant every hundred feet in 

 length for the attachment of fifty feet of hose, which will reach the whole 

 surface without being unwieldy. The hose should be two-inch India-rub- 

 ber, with a large sprinkler at the end, and stop-cock : smaller pipe and 

 hose will prove less satisfactory ; delivering the water too slowly, if it is 

 desired to give the whole surface a thorough wetting. Such an apparatus 

 will distribute a vast amount of water quickly; and, if we wish at all to ap- 

 proach the work of a good shower of rain, we must not stint the quantity. 

 A shower of an inch of rain deposits upon every acre about 26,800 gallons : 

 we often have as much rain in a single thunder-shower of an hour's dura- 

 tion. 



Let us now consider the best means of forcing the water through our 

 pipes. Where a natural head of a few feet, with a good-sized pond or reser- 

 voir to draw from, can be commanded, we have things very convenient; 

 but such opportunities are rare, and we must generally resort to devices to 

 raise the water mechanically. One of the best of these is the hydraulic 

 ram, a simple, durable machine, which needs only a strong spring or small 

 brook with a fall of from four to ten feet. Most of the water runs to waste; 

 while a small portion is forced through a pipe to an elevated reservoir, from 

 which we must draw into our distributing apparatus. This machine works 

 incessantly, day and night and Sunday ; and although it raises only one-f-fth 

 to one-twentieth of the water of the source, the rest running to waste, still, 

 if we have a good large reservoir, it will do good work, and seldom needs 

 repair. Less desirable, though often used in Llolland and the Western 

 States, is the windmill, with force-pump attached. It is less durable than 

 the ram, and works only when the wind blows ; so that we need the high 

 reser^■oir as much as with the ram : it is available, howe\'er, in many places 

 where there is not fall enough to work a ram. Probably a more efficient 

 method for common use would be the force-pump, driven by horse-power ; 

 or, where very large quantities of water are required, by a caloric or steam 

 engine. Wherever we can command a supply of water, at however low a 

 level it may be, this apparatus is ready to force it through our pipes at any 

 time without stint, and needs no provision of an ele\'ated reservoir from 

 which to draw, — a thing most difficult to provide in most cases where much 

 water is wanted. The force-pipe from the pump must be provided with a 



