Rock-bor′--ing ma-chine′.
(Mining.) A machine for drilling holes in rock. Low's machine is operated by air compressed in a reservoir at the mouth of the tunnel and conveyed to the drill-cylinder by a pipe wound on a reel at the back of the apparatus, and so geared as to allow the pipe to unwind when the machine is advancing and recoil it when moving in the reverse direction. By suitably arranged gearing, the boring cylinder may be raised or lowered and adjusted to any required angle. The compressed air is cooled by being forced through water, enabling a higher pressure to be used, and may be diverted from the boring-cylinder to an upright cylinder, from which motion is transmitted to the wheels when it is desired to move the machine. See rock-drill.