Description:
- Object ID: ALSA 2010.06.07
- Made by: Bausch & Lomb Optical Co. Rochester N.Y. U.S.A.
- Model: Unknown.
- Serial Number: Unknown.
- Date Made: Circa 1930.
- Approximate size: 31 cm X 7 cm X 0.2 cm thick
- Accessories: Black covered wooden box (33 cm X 21 cm X 11 cm high) is in two parts. They are attached with two brass hinges on the back and chromed latches on the front. There is a copper-coloured “D” handle on the front over top of a brass key port. The box contains various padded inserts, a screw driver, a brass two pinned attachment and the trough compass previously described along with its mounting thumb screw.
- Condition: fair
Commentary:
The drawing board has a compass needle embedded in it so that the board can be oriented with the top pointing north. It comes with a canvas carrying case which is used to transport and store the drawing board. The alidade comes with a wooden case with a trough compass in it. There is a label inside the case marked “Department of the Interior, Topographical Survey of Canada.” Plane table alidade with box c/w tripod ALSA 2010.06.02 and Plane Table ALSA 2010.06.03.
The instrument is brass and consists of a telescope mounted on a flat plate (31 cm X 7 cm X 0.2 cm thick). Attached to the plate is a trough compass (14.5 cm X 2 cm X 1.5 cm height), a circular bubble (3 cm diameter X 1.5 cm high), two brass thumb knobs for orienting the plate, a raised graduated scale on one end (graduated from 0 to 3000) and markings `BAUSCH & LOMB OPTICAL CO. ROCHESTER N.Y. U.S.A., GSC 89` engraved in the top of the plate. The scope (21 cm long X 3.5 diameter) is mounted on a round pedestal. A striding level is attached to the scope.
The black covered wooden box (33 cm X 21 cm X 11 cm high) is in two parts. They are attached with two brass hinges on the back and chromed latches on the front. There is a copper-coloured “D” handle on the front over top of a brass key port. The box contains various padded inserts, a screw driver, a brass two pinned attachment and the trough compass previously described along with its mounting thumb screw. There are two labels describing the specifications, repair and adjustment record (April 15, 1930 December 5, 1930).
Source of Object: Donated by Steve Cherwonick, ALS#238.
Notes: The Society has only one in their collection.
References: Visit article The Survey Instrument Captain Cook Wanted to Learn – The Plane Table and Alidade for additional information.
Description by: Entered by Ed Titanich on December 23, 2024.