Mahogany and brass reflecting quadrant
- Made:
- 1748 in Fleet Street
- maker:
- Benjamin Cole
Quadrant invented and made by Benjamin Cole, London, 1748. A mahogany frame and handle, with a boxwood arc (in two parts) and brass fittings. Signed on the limb: COLE Inventor and Maker at ye ORRERY in FLEET STREET LONDON No 155. Marked on the inner edge of the limb: Thomas Pearce 1748. Boxwood scale from -0° to 95° every 20'. Brass vernier by 1'. Some of the brass parts and screws are modern replacements. It was used as follows: with their back towards the sun, the observer looked along the sight vane (at the end of index arm), and through the opening in the reflector plate (at the pivot), towards the horizon. While holding the index arm in position, the instrument was then moved upwards until the shadow of the shadow vane fell on the reflector plate. The altitude was then read off the scale and vernier.
Details
- Category:
- Astronomy
- Object Number:
- 1923-477
- Materials:
- complete, wood (unidentified) and brass (copper, zinc alloy)
- Measurements:
-
Overall (as pictured): 480 mm x 480 mm x 70 mm, .74 kg
- type:
- reflecting quadrant
- credit:
- Cooke, Troughton and Simms Limited