20,317. Kellow, M. Sept. 1 Drilling; drills. - A rock drill, of the type wherein a turbine or other small motor is used for rotating the drill, comprises three casings E, D, C, and the turbine-wheel A is held between the casing C and a cover b attached to the casing D with just sufficient clearance over the whole surface of the turbine to permit free working, so that it may not be immersed in water, this object being further assisted, if necessary, by providing vanes on the sides of the wheel. The wheel has a lateral flange a<1> in which curved vanes are mounted with the extremities flush with the outer and inner surfaces of the flange and arranged so that the water from the turbine may be directly discharged into the passage b<1> without touching the body of the wheel. By making the passage b<1> with outwardly-diverging sides, the pressure of the discharge water is raised so that it can be forced through a pipe of small diameter and, if necessary, against an adverse head. The variation of the position of the discharge due to constant head of water and variable speed of the wheel may be allowed for by having the passage b<1> slightly wider than the stream of water, or the discharge nozzle may be attached to a ring rotatable in the cover by a rack and pinion. The inlet and outlet passages b<4>, b<1> register with two concentric nozzles F, F<1> attached by a nut f<3> to the casing E, the nozzles being connected by concentric hose-pipes to a breeches-pipe to convert the annular outlet pipe into a cylindrical pipe. The plug-cock J, Fig. 13, for controlling the supply to the turbine has grooves j<1> connected to the exhaust to minimize leakage between the plug and its shell, water-tight packing j<3> being also provided. The drill tube H, which is of hexagonal form, is fed and withdrawn by water, being provided with a piston h<1> of hard wood working in a cylinder I. Water passes into the passage f<4>, Fig. 3, and is connected by a cock K either to the passage a<4>, in which case water passes from passage a' to the space in front of the piston and the space behind the piston is exhausted through passages i<5>, a<5>, b<1>, or to the passage i<5>, when the drill is fed forward by water passing through passages i<5>, passages i<7>, Fig. 1, and annular passage i<1>, formed by two concentric cylinders I and i. The passage i<1> has a series of collars to stiffen the cylinder i, containing channels for the water. The cylinders i, I may be detached from the casing, for the insertion of drill tubes of varying lengths, by unscrewing the nut i<2>. The four-way cock K, Fig. 10, has a plug k tapered towards its spindle to facilitate adjustment and to take up wear, and a corresponding shell k<1>, which is tapered on the outside in the reverse way. A gauge is used to indicate the pressure of water either in the supply passage f<4> or that acting on the piston, the port l, which leads to the gauge being connected to either of the ports l<1>, a<6> by a cock L. The end of the drill tube is closed by a spring valve h<2>, which is opened at the working pressure to admit water to the front of the drill by passages h<3>, h<4>. The casing is packed at the joints c<2> and also on either side c<3> of the water passages, and has lubricator cups M closed by screw caps m<1>, having grooves for controlling the admission of air, which is shut out when the cap is screwed down tight. The turbine has a flange a<3>, freely mounted on shaft G; this flange carries a spur-wheel N, and the drill is rotated by epicyclic gearing comprising pinions n on the carrier O, which also has a spur-wheel engaging pinions on a carrier attached to the shaft G in which the drill tube is mounted. A series of screwed holes o<3> at different radii in the carriers are used to receive the spindles of the intermediate gear-wheels so that the speed and power may be varied. The Provisional Specification refers to Specification No. 19,292, A.D. 1898, (Abridgment Class Mining &c.].