by the Power Specialty Co. of
New York, using the fall of some rapids in a brook to pump water into a
tank in the attic of a house.

[Illustration: FIG. 45.--Means of securing fall for hydraulic ram.]

In Fig. 45 are shown two methods of securing a fall for hydraulic rams,
recommended by the Niagara Hydraulic Engine Co. The first method shows
no drain pipe, but a long drive pipe; while the second method puts the
ram in an intermediate position, with considerable lengths of each.

There are other methods of utilizing the fall of a stream, but usually
they involve a greater outlay for the construction of a dam and other
appurtenances. An old-fashioned bucket water wheel may be used, which,
though not efficient, utilizes the power of the stream. The wheel may be
belted or geared to a pump directly or may drive a dynamo, the power of
which may in turn be transmitted to the pump. The objection to such
construction usually is that during the summer the small streams which
could be made of service at slight expense run dry or nearly so, while
the expense of damming and utilizing a large stream where the
water-supply is always sufficient is too great for a single house.

_Hot-air engines._

The simplest kind of a pump worked mechanically is the Rider-Ericsson
hot-air engine (see Fig. 46), which is made to go by the expansive force
of hot air. The fuel used may be wood, coal, kerosene oil, gasolene, or
gas, the amount used being very moderate and the daily expense of
maintenance very small.

[Illustration: FIG. 46.--A hot-air engine.]

For a number of years the writer used one of these machines to pump
water from a tank in his cellar to a tank in the attic, so that running
water could be had throughout the house. With an engine and pump costing
$100, it was necessary to pump twice a week for about an hour to supply
the attic tank and to furnish the necessary water for the family. The
following table shows the dimensions, the capacity, and the fuel
consumption of the different styles of pumps made by this company:--

TABLE XII

=========+===========+===========+=========+==========+============+======
| Suction | | | | |
| and | | | | Anthracite |
Size of | Discharge | Capacity | Cu. Ft. | Kerosene | Coal Per |
Cylinder | Pipe | Per Hour | of Gas | Per Hour | Hour | Price
---------+-----------+-----------+-------