Improvements in or connected with Range Finders

8896. Ratcliffe, E. S. June 16. Range-finders.-A distant-base range-finder comprises a gauge plate permanently attached to a rod by which it is held at the required distance from the eye. The gauge plate a may have one or more V-shaped apertures A through which the distant object may be sighted, the aperture used depending upon the known dimensions of the object and the aspect presented. One or both of the sides of the apertures may be stepped ; or they may be straight and provided with notches or graduations, the various ranges being marked on the plate adjacent to the apertures. Alternatively, the apertures may have projections of different lengths and elevations, or separate slots may be provided for each range, or fingers projecting from the plate, one of which is adjustable in position, may be provided. The rod b may be pivotally connected to the plate and may be provided with a clinometer c, so that the elevation of an aircraft may be determined by sighting along the rod. The altitude of the aircraft may then be determined by plotting the range and elevations on a chart. In large forms of the apparatus, the rod may be adjustably mounted on trunnions on a support capable of turning about a vertical axis, and a peepsight may be slidably mounted on the observer's end of the rod.