EXPLORATION SIZE TRANSIT by BAUSCH & LOMB OPTICAL CO.
06-005. American, marked "Patented, Sept 1, 1903, Jan. 30, 1906", and trade marked "BAUSCH & LOMB
OPTICAL CO., Rochester, N.Y." Made of black painted brass and aluminum, with lacquered brass
fittings, and standing 10" high on its 3-screw leveling base (a 12" ivory rule is shown in the
photograph for scale). The telescope is 7 1/2" long, with erecting eyepiece, 1" diameter objective,
rack & pinion objective and spiral eyepiece focussing mechanisms, and a 3 1/2" long bubble level
mounted underneath. The vertical half-circle is 4" diameter, graduated on silver, and mounted on a
5 3/4" tall support attached to the top plate. The horizontal circle is 4 3/8" diameter under the
top plate, with silvered scale, two opposing verniers, and tangent screw control; the compass
housing is 3 5/8" diameter, with 2 3/4" needle. The horizontal limb has bubble vials inlet into the
compass face. The transit is quite complete in its 7" x 8" x 11 3/8" dovetailed mahogany case, with
all of the original accessories except the small plumb bob and the hand magnifier; the telescope has
both the sunshade and the lens cover. The transit is in very good overall condition, with most of
its original finish. While the Gurley exploration transits are the most famous, Bausch & Lomb
transits were, in general, very precise instruments and very innovative in design. A nice example
of an exploration size instrument by one of America's better makers.
