Show A surveying camera A surveying camera styled the bridges leo instrument is being introduced in england it resembles an ordinary camera having a brass bound box with rapid rectilinear lens and double backs and tho usual ground glass ecremen tho camera body turns on a horizontal plato having a graduated rim over which slides a vernier attached to the camera for reading horizontal angles A clamping screw fixes tho camera body to the bottom plate which plato is mounted ou a tripod head provided with leveling screws on top of the bos is fixed a rotating level and telescope mounted on a horizontal arm and fitted with a rack adjustment and scale permitting vertical angles to bo taken this telescope has a vertical wire which bisects tho picture on tho ground screen and is copla nary with a second vertical wiro inside the camera this wiro casts a shadow which is clearly discernible on the sensitive plato or film developed and thus marks tho center line of the picture behind this wiro is a compass mounted on a rack inside the camera by means of which when a photograph is to he taken it can ho moved hack until it just fails to touch the plate tho graduation of ho compass card is carried out on a vertical strip of translucent material through which tho light passes to tho plate thus photographing thereon tho compass bearing A horizontal fiber is also placed inside tho body of the camera similar to the vertical one which when the instrument has been properly leveled indicate the truo horizon engineering news |