bearings, we fastened on two clamps over these flattened parts.
The clamps were made of pairs of hardwood blocks bolted together in the
manner indicated in Fig. 285.

THE WIND WHEEL.

[Illustration: Fig. 285. A Clamp.]

[Illustration: Fig. 286. Wedge for Wind Wheel.]

[Illustration: Fig. 287. Spokes of Wind Wheel.]

[Illustration: Fig. 288. Wind Wheel Blade.]

Our next task was to construct the wind wheel. First we procured three
boards, each 3 inches wide and 3-1/2 feet long. A 1/2-inch hole was
drilled in the center of each board, and then, with these holes
coinciding, the boards were nailed together, with their ends projecting,
like spokes, equally distant from each other. Six wedges were now made
of the size indicated in Fig. 286. These were made of a 2 x 4-inch
scantling, sawed diagonally in two and then planed down to the given
dimensions. The wedges were now nailed firmly to the spokes, as shown in
Fig. 286. For the blades we used six thin boards, each about 4 feet
long. Each blade measured 10 inches in width at the outer end, and
tapered down to a width of 3 inches at the inner end, as illustrated in
Fig. 288. The blades were now securely nailed to the wedges, and their
outer ends were braced together by means of wires stretched from the
forward edge of each blade to the rear edge of the next one ahead. The
wheel was then fitted onto the shaft and nailed to one of the clamps. In
this way it was practically keyed to the shaft.

We did not make any vane for our windmill. It did not need any. The wind
nearly always blew either up or down the river, more often up the river,
for the prevailing summer winds in that part of the country are
southerly. But, aside from that, east and west winds could not very well
reach us on account of the hills on both sides of the river. The wheel
was set facing the north, because the strongest winds came from that
direction, and as an extra brace against these winds we stretched wires
from the projecting end of the shaft to the center of each blade.

A SIMPLE BREAK.

[Illustration: Fig. 289. The Wind Wheel.]

A brisk northerly wind was blowing when we set the wheel in place, and
it began to revolve at once, before we could nail it to the clamp. To
stop it we nailed a stick of wood to the tower, so that its end
projected in the path of the blades and kept the wheel from turning
around. This brake was swung up to the dotted position illustrated when
we were ready to hav