162. Water-wheel governor acting on the same principle as 161, but by different means. The governor is driven by the top horizontal shaft and bevel-gears, and the lower gears control the rise and fall of the shuttle or gate over or through which the water flows to the wheel. The action is as follows:—The two bevel-gears on the lower part of the center spindle, which are furnished with studs, are fitted loosely to the said spindle and remain at rest so long as the governor has a proper velocity; but immediately that the velocity increases, the balls, flying further out, draw up the pin which is attached to a loose sleeve which slides up and down the spindle, and this pin, coming in contact with the stud on the upper bevel gear, causes that gear to rotate with the spindle and to give motion to the lower horizontal shaft in such a direction as to make it raise the shuttle or gate, and so reduce the quantity of water passing to the wheel. On the contrary, if the speed ot the governor decreases below that required, the pin falls and gives motion to the lower bevel-gear, which drives the horizontal shaft in the opposite direction and produces a contrary effect.