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 have the wheel revolve, but it could be thrown down at any time to stop it.

Fig. 289. The Wind Wheel.