552 Farm Mechanics. 



The best place for the cyclinder in any well, if there is 

 a sufficient depth of water to permit of it, is several feet be- 

 low the level of the water. When the cylinder is placed be- 

 neath the water it is where it will always be "primed" 

 and where there is little danger of lowering the water by 

 pumping to a level at which the pump works imperfectly. 

 The general rule to follow then is to place the cylinder 

 as low in the well as practicable, or so far below the sur- 

 face of the water that it will always be covered. 



699, Hydraulic Earn. Where the conditions are favor- 

 able for the use of the hydraulic ram for domestic water 

 supply it is one of the cheapest, most satisfactory and 

 efficient means yet devised for lifting water. 



The hydraulic ram consists of (1) a drive pipe, (2) 

 an air chamber, (3) an impetus valve, (4) a discharge pipe 

 and (5) a discharge valve. The principle of the hydraulic 

 ram is that of using the inertia or momentum of a large 

 volume of water to raise a fraction of the same water to 

 the desired hight. The water is allowed to flow through 

 the drive pipe until it acquires velocity enough to close 

 the impetus valve and this immediately stops the column 

 of water in the drive pipe, causing it to act like a water 

 hammer to force open the discharge valve leading into 

 the air chamber, compressing the air by means of a portion 

 of the water which is driven in. As soon as the column 

 of water in the drive pipe is brought to rest the impetus 

 valve falls down of its own weight and this 'allows the 

 water in the drive pipe to flow at full velocity again' until 

 it is finally moving fast enough to close it once more, when 

 the sudden stopping forces another charge into the air 

 chamber. In this way the steps are continually repeated, 

 thus maintaining a steady supply of water, the compressed 

 air forcing the water into the discharge pipe leading to 

 where the water is desired. 



The hydraulic ram can be used where there is only 

 a comparatively small fall, of even two or three feet, but 

 where it is used to supply drinking water from a spring the 



