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Type 6/18
Aperiodic compass
Bowl: Black painted brass. Filler plug at side, expansion chamber at base of bowl. An aperture is provided in side of bowl for illuminating spider at night. A carrier for corrector magnets is fitted below the frame which supports the compass. Inside of bowl painted white. Fixed arrow line mounted inside bowl below verge glass, this line is fitted with a cup to prevent card (spider) coming off pivot. A rotatable verge ring, graduated to 360 degrees carries six parallel wires (for grid steering).
Card: Spider of eight elements, marked at N, S, E & W. Red at north point.
Needle: Six needles slung beneath the card.
Pivot: Unsighted but appears to be of the inverted pivot type engaging on a steel pivot carried on a bridge attached to base of bowl.
Bowl: Black painted brass. Filler plug at side, expansion chamber at base of bowl. An aperture is provided in side of bowl for illuminating spider at night. A carrier for corrector magnets is fitted below the frame which supports the compass. Inside of bowl painted white. Fixed arrow line mounted inside bowl below verge glass, this line is fitted with a cup to prevent card (spider) coming off pivot. A rotatable verge ring, graduated to 360 degrees carries six parallel wires (for grid steering).
Card: Spider of eight elements, marked at N, S, E & W. Red at north point.
Needle: Six needles slung beneath the card.
Pivot: Unsighted but appears to be of the inverted pivot type engaging on a steel pivot carried on a bridge attached to base of bowl.
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Object Details
| ID: | ACO0319 |
|---|---|
| Type: | Aperiodic compass - aircraft |
| Display location: | Not on display |
| Creator: | Bennett, Dr. G. T.; Campbell, Colin Mappin & Webb |
| Places: | Sheffield |
| Date made: | 1919 |
| Credit: | National Maritime Museum, Greenwich, London, Admiralty Compass Observatory |
| Measurements: | Overall: 145 mm; Diameter: 150 mm |