The blades are of hard-wood ten inches wide and the length of the barrel. One edge of each blade is cut to conform with the bilge of the barrel as shown at A, and with three or four long screws each blade is made fast to the barrel at the middle. The ends of the barrel are replanked so as to build their surface even with the projecting edges of the staves, then some matched boards are nailed or screwed to the heads to bind together the ends of the blades. Screws are passed through the boards and into the ends of the blades to make them secure, and in this manner a hollow wheel is made with pockets around the outside.
A square hole should be cut in each end of the barrel and into them an axle is driven. It is provided with rounded bearings and square end. When swung in a carriage and connected a powerful wheel will be the result if the force of water is sufficient to drive it.
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