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having a knuckle connection. The lower member of each hinge is secured to the npper portion of the door, the uppe· r member of each hinge being attached to the eM riage. A rod connects a lift-lever fulcrumed npon the door with the carris ge. A bolt held to slide and rock upon the door is provided with a lateral cam projection adapted to engage the door when the bolt IS rotated. A keeper is provided for the bolt independently of the door and also a locking device for the bolt. The device is apdoi:10.1038/scientificamerican07091898-29a fatcat:q3trg4kshbam5hocmhbo2tg3j4