Gurley Surveyor's Transit with Burt's Patent Solar Attachment
- Sold for:
- Clocks, Watches & Scientific Instruments - 2345
- Date / Time :
- July 29, 2006 10:00AM
Gurley Surveyor's Transit with Burt's Patent Solar Attachment, with original bronzed finish (some wear), 4 3/4-inch silvered dial engraved W. & L. E. Gurley, Troy, N.Y., with fleur-de-lis at North, East and West points reversed, blued-steel needle with shaped tips on central brass hub with clamp, inside vernier, and needle ring divided 0-90° in four quadrants with divisions extending to inner rim, the horizontal plate with two vials and opposite verniers with tangent-screw adjustment, the twin A-frames supporting 3-inch radius vertical half-circle with silvered arc divided 0-90-0°, 6-inch vial, 11-inch lg. telescope and solar attachment with horizontal hour ring divided I - XII, 5-inch radius declination arc and corresponding arm with vernier, solar lenses and diametric silver plates mounted on opposite blocks, on four-screw leveling base, ht. level 16 in., on tripod; and a fitted mahogany case with Gurley label in lid.
Note: The original version of the solar compass was invented by William Austen Burt in 1835 to solve the problem of aberrations caused by local attractions of the magnetic needle. His invention quickly became a requisite for all U.S. land surveys. Gurley advertised their solar attachment as being "essentially the solar apparatus of Burt placed upon the cross bar of the ordinary transit."