Village Sanitary Economy. 
235 
stress on tlae valves then becomes too great for tlieir long 
endurance. One of the special features of the ram is, that a 
portion of the same water 
that works it is raised as 
the supply ; so that, unless 
the water of the stream is 
suitable for^ domestic pur- 
poses, the ram is inapplic- 
able. One of the best 
forms of ram is shown in 
the annexed drawing. As 
the hydraulic ram differs 
in principle from all other 
means of raising water, 
so its useful effect varies 
according to a different 
law. For example, when 
the elevation to which water has to be raised amounts to about 
eight times the fall which works it, the useful effect is 66 per 
cent. ; but when the elevation is ten times the fall, the useful 
effect is reduced to 50 per cent., while at twenty times the fall, 
the useful effect is only 18 per cent.' 
To give an example reduced to gallons raised per minute, so 
as to judge of effects under different circumstances, let it be 
assumed that 40 gallons of water per minute are at command, 
having an available fall of 10 feet — then the following calcula- 
tions apply to different heights 
If lifted 80 feet x = 3^ Erallons per miuute. 
100 ao ^ 
oO 40x10 „ „ . , 
" " "ICXT ^ — ^100 — ■ ~ gallons per minute. 
OAA IS 40x10 1 1 f n • . 
„ JOO ,, — — — X . = ird 01 a "allon per minute. 
100 2W ^ " ^ 
These figures will suffice to show that the hydraulic ram should 
not have to lift more than ten times the height of the fall, where 
economy is the object aimed at. 
In cases where the water which furnishes the power is not of 
a quality suitable for domestic use, and where there is other 
and better water at hand, or where the quantity required is 
greater than the ram can lift, or where the elevation is higher 
than the ram can economically raise the required quantity, 
pumps worked by either water-wheels or turbines can be more 
appropriately used than the ram. The water-wheel is slow in 
movement, and therefore ought to be adapted to comparatively 
slow-moving pumps of large capacity and regular, resisting power. 
