very unique and unusual freestanding heavy duty baked black enameled cast iron three-legged scientific measuring instrument designed and fabricated by the sargent-welch scientific company, buffalo, ny. possibly used in an optometrist's office. the housing is comprised largely of cast iron with a then sheet of steel protruding from the face. the three-legged base is structurally sound and stable. the rotating circular-shaped steel scale contains lightly incised numbers, markings, geometric shape, etc. the largely intact black enameled finish against a weathered white enameled background provides added contrast and/or visibility. the scientific instrument likely had additional components. likely fabricated between 1915-1925. measures 14 inches in diameter x 8 x 17 1/2 inches.