in mechanics, a machine for driving piles, fitted with a windlass and winches at each end, where eight or nine men heave, and round which a rope is reeved that goes over the wheel at the top: one end of this rope is seized to an iron monkey, that hooks to a beetle, of different weights, according to the piles they are to drive, being from eight to thirteen hundred weight; and when hove up to a cross piece, near the wheel, it unhooks the monkey, and lets the beetle fall on the upper end of the pile, and forces the same into the ground: then the monkey's own weight overhauls the windlass, in order for its being hooked again to the beetle.