308 Hydraulics for Farmers. [June, 



heiofht to which the water is elevated through k, while owing to 

 the same cause operating in an opposite manner at h, the air in h 

 is raritied, or under less than the pressure of the atmosphere. As 

 water under pressure, in contact with air, has the property of ab- 

 sorbing more or less of it, and then liberating it; when the pres- 

 sure is removed, the air in a has a tendency to diminish, and that 

 in h to increase in quantity; but the position of the valves in this 

 machine is such, that when it is in action, a is constantly replen- 

 ished from the overplus in h, for the recoiling movement in i, 

 above mentioned, which allows valve g to open, draws in a few 

 bubbles of air from h,f, at o, which air lodges in the cavity under 

 n, and is driven into a, by the next pulsation of the water in i. 



Farmers, manufacturers, and others, have frequently attempted 

 to carry water over elevated ground to some situation below the 

 fountain head, but have been troubled, and often compelled to 

 abandon the plan, from an accumulation of air in the more ele- 

 vated portions of the pipe, which, in the course of a few days, 

 cuts off the stream entirely, and requires it to be re-filled. This 

 is owing either to a want of sufficient fall between the level of 

 the supply and the point of discharge, or to some contraction in 

 the pipe, either of which causes, acts by checking the current 

 through the pipe to that degree, that the air liberated from the 

 water, (owing to the diminished pressure to which the water is 

 subjected in the higher portion of the syphon,) remains in the 

 pipe. The only remedy is to obtain more fall, or give the pipe a 

 freer apperture, until the current has sufficient velocity to carry 

 the air through. A velocity of between one foot and eighteen 

 inches per second, is ordinarily sufficient to accomplish this. 



The quantity of water which the machine above described con- 

 sumes, may be, to a considerable extent, regulated by a small 

 crank, which enters at right angles with the plane of the section 

 behind valve g, which, when turned, gives the valve more or less 

 play, and may, if desired, be made to close it, and stop its action 

 entirely. There is also a small fixture for opening and starting 

 the action of the valve. When the apparatus overdraws its sup- 

 ply, and stops from that cause, the syphon pipes do not empty 

 themselves of water, as would be the case with an ordinary 

 syphon: the first few bubbles of air then ascend the short leg of 

 the syphon, disturb the action of the valves in such a manner that 

 they cease to operate, and the pipes i n remain full of water. 



In the foot of the short leg of the syphon is a short plug, which 

 may be drawn up a little distance into and thrust down out of the 

 pipe, by means of an iron rod attached to it, and passing up along 

 side the pipe, to a convenient place for reaching it. This plug 

 is drawn up into the pipe for the purpose of stopping it when the 

 syphon is filled, and is also used in starting the machine, when 



