Brass construction. The instrument consists of a plate supported by an L-shaped arm and foot. A thumbscrew on the plate causes a pencil below to describe the figure, through a train of four gears, the last of which carries the pencil at the end of an arm. (Robert P. Multhauf, "Catalogue of Instruments and Models," 1961).

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).

A black walnut box containing two measuring tubes; one with 1 1/4" diameter screen disc and 5" long tube and one with 6" screen disc and 2 3/4" long tube. This is an experimental instrument fabricated of discs of bronze or brass screen, attached to a brass tubing to constitute an anemometer. (Robert P. Multhauf, "Catalogue of Instruments and Models," 1961).