nArcographAn instrument for drawing a circular arc without the use of a central point; a cyclograph.
Century Dictionary and Cyclopedia
narcographAn instrument for drawing an arc without the use of a central point. It consists of a thin and pliable strip of wood or metal, the ends of which are attached to a straight bar, which can be shortened or lengthened to form a chord of the required arc. It is used as a templet.