July 20.] THE NEW ZEALAND GAZETTE. 1351

have an axial hole through them from end to end, and the piston’s actuating-fluid is controllably supplied automatically to the axial hole in said rock-cutting drill, and means for leading a supply of water into the axial hole in said drill-bit and for mingling the air and water together and for discharging them in the bottom of holes in rock while drilling them, substantially as described. (17.) In a rock-drilling engine, a rock-cutting drill arranged to be struck by the reciprocal movements of the piston, and provided with a collar, projection, or shoulder adjacent to its striking-end, adapted to form a locking, securing, and positive means for holding and rotating said drill-bit, and a passage axially through said cutting-drill, arranged to conduct a portion of the piston’s actuating-fluid from the cylinder to the cutting-point of said rock-cutting drill, and a valve for controlling the supply of actuating-fluid flowing to the drill-bit, substantially as described. (18.) In a rock-drilling engine, a drill-bit arranged to project into the cylinder of the drilling-engine, and arranged to be operatively struck upon its end by the reciprocal movements of the engine’s piston, and containing a passage or conduit from said engine’s cylinder to or adjacent to said drill-bit’s cutting-point, and a water-passage or tube through said drilling-engine to said passage in said drill-bit, means to provide a suitable water-supply for said passage and said drill-bit, whereby a commingled supply of the cylinder’s actuating-fluid and water is conveyed from said drilling-engine through said drill-bit to its cutting-point and to the bottom of holes in rock while drilling them, substantially as described. (19.) In a rock-drilling engine, a suitable cylinder, a reciprocal piston, a suitable controlling-valve and suitable feeding-mechanism and drill-bits arranged to project into said cylinder into the reciprocal path of said piston, and arranged and adapted to be struck directly on their cylinder-invading ends by the reciprocal movements of said piston, and containing a passage or conduit for the actuating-fluid of said rock-drilling engine, opening into or communicating with said engine’s cylinder, and extending through said drill-bits to or adjacent to their cutting-points, a water-conveying tube or conduit connecting with the said passage or conduit in said drill-bits, means to provide a suitable water-supply and to mingle with it a portion of the cylinder’s actuating-fluid, substantially as described. (20.) In a rock-drilling engine, the combination with the cylinder and the piston, of a drill-bit, containing an axial hole from end to end, and extending into the reciprocal path of the piston and passage in said cylinder, open to a controlled supply of the engine’s actuating-fluid, an axial bore through said piston, a tube in said bore projecting into the hole in said drill-bit, and means to provide a suitable water-supply under pressure, substantially as described. (21.) In a rock-drilling engine, the combination of the cylinder, the piston, the cylinder-heads, the chuck-sleeve, the chuck, and the hollow drill, with a liquid- or water-conveying tube through said piston, connected with said hollow drill, and a valve-controlled passage from said cylinder adapted to allow a suitable supply of the cylinder’s actuating-fluid to flow into said hollow drill, whereby a combined stream of liquid and actuating-fluid is caused to flow through said drill-bit to the bottom of holes while drilling them, and means, including a valve, for controlling the volume and pressure of said liquid and actuating-fluid stream, substantially as described. (22.) In a rock-drilling engine, the combination with the cylinder, of a piston having an extension hammer-bar, the front cylinder-head, the chuck-sleeve, the chuck, the chuck-ring, and the cupped washers and rings surrounding said hammer-bar, with a hollow drill-bit held loosely to said chuck-sleeve and chuck, and arranged to be instantly withdrawn from or inserted in said chuck-sleeve and chuck, and provided with means for defining its operative position in said chuck-sleeve and chuck and to said cylinder and piston, and with a fixed tube projecting from the rear end of said cylinder freely through said piston, and extending into said drill-bit, substantially as described. (23.) In a rock-drilling engine, the combination with the cylinder and the piston, of a hollow drill-bit projecting into said cylinder into the reciprocating path of the piston, and arranged to convey a portion of the piston’s actuating-fluid to the bottom of holes while drilling them, with a water-tube projecting into said drill-bit for supplying water under pressure and mingling it with the actuating-fluid of said drill-bit, and discharging into the bottom of holes, while drilling them, a combined stream of actuating-fluid and water, and means for preventing the water from entering said cylinder, substantially as described. (24.) In a rock-drilling engine for expelling rock-cuttings from holes while drilling them and for laying the rock-dust, a substantially combined mixed or commingled operative supply of any suitable watery liquid and an operative portion of the engine’s actuating-fluid, discharged steadily or intermittently during operative rock-drilling, or at each stroke of the piston, or at suitable intervals, in any suitable operative form, such as a spray or jet or as a stream, into the bottom of holes in rock while drilling them, and means for preventing the water from entering said cylinder, substantially as described. (25.) In a rock-drilling engine, the combination with the cylinder and the piston, of the front, the rear, and the supplementary cylinder-heads, a hollow drill-bit projecting into the path of the piston, and a water-inlet tube secured to said rear cylinder-head and projecting through said piston into said drill-bit, and an air-passage leading from said cylinder to said drill-bit, substantially as described. (26.) In a rock-drilling engine, the combination with the piston, the cylinder, and the valve and chest, of the drill-bit, the supplementary cylinder-head, the rifle-bar, and the rear cylinder-head having a water-inlet tube secured thereto and projecting therefrom loosely through the axial centre of said rifle-bar and said piston into the striking-end of said drill-bit, and an actuating-fluid passage leading from the valve-chest and cylinder to said drill-bit, substantially as described. (27.) In a rock-drilling engine, the combination with the drill-bit, the cylinder, the valve-chest and valve, the piston and the rifle-bar, axial holes through said rifle-bar and piston, a water-inlet tube projecting loosely through said axial holes into said drill-bit, adapted to conduct a stream of water under pressure through said tubes and drill-bit, a valve for controlling the flow of said water, and a valve-controlled actuating-fluid passage leading from said valve-chest and cylinder into said drill-bit, and means for preventing a harmful flow of water into said cylinder, substantially as described. (28.) In a rock-drilling engine, the combination of a piston having a rifle-bar, a drill-bit having an axial hole through it, a cylinder having a water-conveying tube projecting through said rifle-bar and piston into said drill-bit, a water-passage to said tube, a valve adjacent to said tube for controlling said passage, means for mingling said water with a portion of the engine’s actuating-fluid, means for conducting said actuating-fluid and water in a combined stream to the bottom of holes in rock while drilling them, and means for preventing a harmful flow of water into said cylinder, substantially as described. (29.) In a rock-drilling engine, the combination with the hollow drill-bit, of the chuck-sleeve, the chuck, the cylinder, the piston having a hammer-bar extension, the rifle-bar, and the rear cylinder-head having a water-inlet tube projecting through said rifle-bar and piston into said drill-bit, a passage around said tube from said cylinder into said drill-bit, and means, including cupped washers arranged to surround the piston’s hammer-bar, for preventing a harmful flow of water into said cylinder, substantially as described. (30.) In a rock-drilling engine, the combination with the cylinder and the piston of a hollow drill-bit mounted to be turned step by step by said piston, a water-inlet tube projecting into said drill-bit, and a valve-controlled actuating-fluid passage from said cylinder into said drill-bit, substantially as described. (31.) In a rock-drilling engine, the combination with the cylinder, the piston, the cylinder-head, and the sleeve of a hollow drill-bit projecting into said cylinder, means for conveying a portion of the cylinder’s actuating-fluid to its cutting-point, of a conduit adapted to convey a stream of water under pressure to said drill point, a rear cylinder-head, a passage in said cylinder-head for said water, a valve adapted to control the admission and volume of said water, and a water-inlet coupling adapted to connect with a source of water-supply on either side of said cylinder, substantially as described. (32.) In a rock-drilling engine, the combination with the piston having an axial hole, the drill-bit, the rifle-bar having an axial hole, and the back cylinder-head carrying a water-inlet tube projecting through the axial bores of said rifle-bar and piston, with a water-inlet coupling rotably mounted on said cylinder head, a passage from said coupling to said tube, and means, including a nut and thread, for packing said coupling against leakage, substantially as described. (33.) In a rock-drilling engine, the combination with the piston and the hollow drill-bit, of the back cylinder-head, the water-inlet tube projecting therefrom through said piston and into said drill-bit, a passage through said cylinder-head for the admittance of water under pressure to said tube and drill-bit, a valve controlling said passage and a suitable packing-device for said valve, substantially as described. (34.) In a rock-drilling engine, the combination of the hollow drill-bit, the piston, the rifle-bar, and the back cylinder-head, with a tube projecting loosely through bores in said rifle-bar and piston, and with a water-inlet coupling having a hose- or pipe-connecting nipple, and a passage from said coupling to said tube, substantially as described. (35.) In a rock-drilling engine, the combination with the back cylinder-head, of the rotatable water-coupling mounted thereon, a shoulder or abutment adjacent to said coupling, a washer between said coupling and said shoulder, a second washer on the opposite side of said coupling, and a nut threaded to said cylinder-head adapted to tighten said washers and coupling against leakage, substantially as described. (36.) In a rock-drilling engine, the combination of the supplementary cylinder-head, the rear cylinder-head secured thereto, the water-inlet tube, the rifle-bar revoluble on said tube, the piston arranged to