15,147. Wise, W. L., [Bethlehem Steel Co.]. July 7. Mountings; sights and methods of sighting.-Relates to range-finding and automatic sighting- apparatus for ordnance. At an outlying station the azimuth angle between a given line and the target is observed, and then transmitted by telephone &c. to each gun of a battery. By the adjustment of an instrument to this angle, and the training of the gun upon the target, the angle is determined and the sighting automatically effected. Fig. 11 shows a plan of the apparatus adapted for range finding simply. Fig. 15 is a diagram illustrating the principle upon which it acts. An arm 11 is pivoted at x to a graduated disc 12, upon which a second arm 13 is pivoted as shown. These two arms are grooved longitudinally and connected by a block 14, which is traversed along the arm 11 by a screw 17 rotated by a thumb-nut 31. A telescope 54 is mounted parallel to the axis of tha screw 17 and upon the arm 11. The instrument is mounted to rotate on a fixed pedestal, to which a spur-wheel 48 is attached. With this spur-wheel engages a worm 53 on a shaft rotated by a hand-wheel 40. By means of this wheel, therefore, the arm 11 can be rotated in azimuth to bring the sighting-telescope 54 to bear upon an object. By means of a second wormshaft 22, driven from the wheel 40, rotary motion is given to the sector 12 at such a rate that its diametral edge remains pointing in the same direction during the training of the arm 11. In operation therefore an object n, say, is sighted at an outlying station 15, and the azimuth angle between the directions of the object n and the instrument station is determined. This angle is transmitted and the arm 13 set to it on the disc 12 by operation of the nut 31, after the telescope has been trained upon the object by the operation of the wheel 40. The range can then be read off on a scale 34. When the apparatus is used in combination with ordnance for sighting purposes, the axis of rotation x of the sector is mounted as close as convenient to the centre of rotation of the gun mount, and the gear for the rotation of the sector is coupled to that for traversing the gun. Fig. 7 shows the traversing-shaft 40, which, by means of pinions 39, 40 and the shaft 38, drives simultaneously the apparatus for rotating the sector. For the purpose of effecting simultaneously the setting of the arm 13 and the elevation of the gun, the hand-wheel 41 drives through spur gearing a shaft 44 carrying a worm 45, which engages with and drives a shaft 47. On the shaft 47 is mounted a spiral groove, which engages with a stud on the gun cradle, and thus elevates it when the wheel 41 is turned. The simultaneous adjustment of the azimuth angle is effected by spur gearing which connects the shaft 44 and the screw 17 of the range finder. To adjust the gun initially, the gear for driving the sector includes a shaft in two lengths, which admit of relative adjustment.