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Dry compass
Card- Mica covered with paper. White with black and white markings, graduated to 1/4 points and quadrantally in degrees.
Needle- Four compound edge bar needles made of two laminations of steel, with ends slightly bevelled off, spaced 1.7" apart, 2 x 7.25" and 2 x 5" long. Attached to a light metal ring which is screwed to card. A brass framework, attached to the inner needles, is fitted at centre and carries a threaded tube in which the jewel cap is fitted. Four small screws project downwards from centre of frame.
Pivot- Small cone-shaped brass pivot cap with jewel at top, attached to a threaded tube which screws into the brass framework at centre of card and projects 1" above card.
Needle- Four compound edge bar needles made of two laminations of steel, with ends slightly bevelled off, spaced 1.7" apart, 2 x 7.25" and 2 x 5" long. Attached to a light metal ring which is screwed to card. A brass framework, attached to the inner needles, is fitted at centre and carries a threaded tube in which the jewel cap is fitted. Four small screws project downwards from centre of frame.
Pivot- Small cone-shaped brass pivot cap with jewel at top, attached to a threaded tube which screws into the brass framework at centre of card and projects 1" above card.
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Object Details
| ID: | ACO0944 |
|---|---|
| Type: | Dry compass |
| Display location: | Not on display |
| Creator: | Henry Barrow & Co |
| Date made: | 1837-1840; 1837-40 |
| Credit: | National Maritime Museum, Greenwich, London, Admiralty Compass Observatory |
| Measurements: | Overall: 50 mm; Diameter: 190 mm |