234 Village Sanitarij Economy. 
the water in the well to the mouth of the delivering pipe, the 
pressure on the pump when at rest amounts to 26 lbs. per square 
inch, and when working this pressure is much increased by the 
friction due to tortuous and narrow passages, and the necessity 
of overcoming inertia. Under full force all deficiencies of 
strength are shown, and the superiority of the engineer's over 
the plumber's pump made manifest. There are three kinds of 
pumps which will be found serviceable for the supply of villages 
with water, viz., the bucket pump, the plunger pump, and the 
combined plunger and bucket pump. The two former, when 
worked in sets of three, will give a continuous stream, but the 
last pump acting both in the up-stroke and the down-stroke will 
give a stream sufficiently continuous for all practical purposes 
by itself when combined with an air vessel, which prevents 
those sudden shocks to the machinery which would otherwise 
occur. The cost of all the machinery in the case of either 
the centrifugal pump or the lift and force pumps, when worked 
by wind power, and supplemented by horse-power, would be 
about the same as that of the noria. 
III. Tlie Use of a Stream near at hand, but at a Lower Level 
than the ViVage, both as a Supply and as Motive Power to raise the 
required Quantity. — Three descriptions of machinery present 
themselves for consideration, each being preferable under certain 
conditions. The machines are the hydraulic ram, the turbine 
and pump, and the undershot wheel and pump.* Where the 
quality of the water is suitable, the power small, and the elevation 
to which the supply has to be raised is not more than 10 times 
the fall, there is nothing equal in simplicity, efficiency, and 
cheapness to the hydraulic ram. With a fall, for instance, of 8 
feet, a ram will raise 4000 gallons daily to a village half a mile 
off, 40 feet higher than the supply if the quantity of water at 
command is 38 gallons a minute. The ram acts upon a prin- 
ciple different from that of any other hydraulic machine, inas- 
much as by concentrating into a small quantity of water the force 
accumulated by motion of a larger body, the small quantity 
is raised to the required height. The greatest amount of 
water a ram will raise does not exceed half of what a horse 
would accomplish if its power could be brought to bear in the 
most favourable way ; but as the ram is self-acting, and never- 
ceasing if the water acting through it remains the same, the 
advantages of the ram over the horse, though it apparently does 
only half the work, are very superior. 
The fall to the ram should in no case exceed 20 feet, as the 
* The writer is indebted for much of the information respecting the use of the 
ram, the turbine, and the wheel, as well as that respecting pumping machinery 
generally, to Mr. Arthur Rigg, er.gineer of the George-street Works, Chester. 
