This ship's log consists of a vertical-turned brass rod with a slot in the top for a pulley or fulcrum which is missing. A pair of shorter rods support between them a pivoted brass quadrant which is scaled but not numbered. The base is scaled radially from the axis of the quadrant. Inscribed "Porters A Conno(e)r" on the base. Paper on underside label marked "Porter Constant Log." (Robert P. Multhauf, "Catalogue of Instruments and Models," 1961).