1847.] 



Hydraulics for Farmers. 



299 



Fig. 4. Montgolfier's Ram. Fig. 3. 



Explanation. The above is a sectional and simple form of 

 Montgolfier's ram. The head or motive column descends from a 

 spring or brook A, through the pipe B, near the end of which 

 an air-chamber D, and raising main F, are attached to it, as 

 shown in the figure. At the extreme end of B, the orifice is 

 opened and closed by a valve E, instead of the cock in White- 

 hurst's machine before described. This valve opens downwards, 

 and may either be a spherical one, as in Fig. 4, or a common 

 spindle one, as in Fig. 3. It is the play of this valve that ren- 

 ders the machine selt-acting. To accomplish this, the valve is 

 made of, or loaded with such a weight, or adjustment of the 

 spring, as just to open when the water in B is at rest; then, as 

 in shutting the cock of Whitehurst's machine, a portion of the 

 water will enter, and rise in F, the valve in the air-chamber pre- 

 venting its return. Meantime the water in B has been brought 

 to rest, and relieved for a moment of the pressure and rush of wa- 

 ter, the pressure is insufficient to sustain the weight of the valve 

 E, which drops, and reopens the outlet hole at E, when the cur- 

 rent is again put in motion, and acquires force enough to close 

 valve E, when another portion of the water is again forced into 

 the air-vessel D, and pipe F; and thus the operation is repeated, 

 as long as the spring or brook affords a sufficient supply, and the 

 apparatus remains in order. This process, or pulsation, like the 

 click of a clock, continues until accident or wear stops the work- 

 ing of the valves. The valves make from twenty-five to sixty 

 strokes per minute. The machine is set in motion by pressing 

 down the valve E, Fig. 3. 



The surface of the water in the spring or source, should ahvays 

 be kept at the same elevation, so that its pressure against the 

 valve E may always be uniform; otherwise the weight of E would 

 have to be adjusted, as the surface of the spring rose and fell. 



