WATER-WHEELS
An Undershot-wheel
For a brook an undershot-wheel can be made with two round ends and ten or twelve blades according to the size of the wheel. For an efficient one the wheel should be thirty-six or forty-eight inches in diameter and thirty inches wide. Two ends are made from matched boards held together with battens as shown in Fig. 4 A. These are arranged on a square axle and the blades are made fast between them with long screws or steel nails. Fig. 4 B.
A Power-wheel
To utilize the power from a rapidly running brook place two tree-trunks across the brook about six feet apart as shown in Fig. 5. On top of these timbers attach two spruce beams eight or ten inches wide and two inches thick, and anchor them well with spikes and check-blocks. At the middle and on top of both timbers cut notches for the axle to fit in and provide them with metal straps to hold the axle in place. A long axle leading to the land can be supported on a short timber attached to stout stakes driven in the ground, and another bearing and strap will hold this from jumping with the rapid revolutions of the wheel. A wooden pulley may be arranged at the end of this axle, and from it the power can be taken off by means of belting or rope.
POWER-WHEEL AND WHEEL-RACE
Another arrangement for this wheel will be to swing it in a cradle or frame so that one end of it may be lifted to reduce the speed or power of the wheel, the other end being securely attached to a tree-trunk with hinges.
A Wheel-race
The water from a wide, shallow brook may be directed so as to throw its full force against the blades of a wheel by digging it out at the middle and damming it at the sides as shown by the diagram of a modified brook (Fig. 6). The dams should be solidly built and if possible cribbed to prevent their washing away.