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Cross-staff
An ivory staff and four decoratively engraved ivory vanes. The sky-end of the staff is pyramid-shaped. The vanes are in two parts and are held together by brass pins. The fourth vane has a fixed ivory horizon. The beginnings of the scales on all four sides are marked ‘Altitude’, and ‘Complement’ for the zenith distance.
The scales are from 90° to 34° (side one); from 90° to 20° (side two); from 90° to 10° (side three) and from 90° to 4° (side four), this is vice versa for the zenith distance. The maximum reading accuracy is 10 arcminutes for the sides one to three, and 5 arcminutes for side four.
Signed on side one: ‘Thomas Tuttell Charing + Londini fecit’
Signed on side two: ‘Fait par Tho: Tuttell Ingenieur de sa MAIESTÉ BRITANIQUE | pour les Instruments Mathemathiques á LONDRES’.
Cross-staves were normally made of wood and few have survived. The cross staff was probably not meant for use on board a ship. It was part of a presentation set including a backstaff (NAV0040), two Gunter’s scales (NAV0108 and NAV0107), and a sector (NAV0166), all fitting in a lyre case. The inscription may point towards an original French owner.
The scales are from 90° to 34° (side one); from 90° to 20° (side two); from 90° to 10° (side three) and from 90° to 4° (side four), this is vice versa for the zenith distance. The maximum reading accuracy is 10 arcminutes for the sides one to three, and 5 arcminutes for side four.
Signed on side one: ‘Thomas Tuttell Charing + Londini fecit’
Signed on side two: ‘Fait par Tho: Tuttell Ingenieur de sa MAIESTÉ BRITANIQUE | pour les Instruments Mathemathiques á LONDRES’.
Cross-staves were normally made of wood and few have survived. The cross staff was probably not meant for use on board a ship. It was part of a presentation set including a backstaff (NAV0040), two Gunter’s scales (NAV0108 and NAV0107), and a sector (NAV0166), all fitting in a lyre case. The inscription may point towards an original French owner.
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Object Details
| ID: | NAV0505 |
|---|---|
| Collection: | Astronomical and navigational instruments |
| Type: | Cross-staff |
| Display location: | Not on display |
| Creator: | Tuttell, Thomas |
| Date made: | circa 1700 |
| Exhibition: | Ships, Clocks & Stars: The Quest for Longitude |
| Credit: | National Maritime Museum, Greenwich, London, Caird Collection |
| Measurements: | Overall: 796 x 14 x 14 mm; the vanes are 506, 292, 136, and 101 mm in length. |
| Parts: | Cross-staff |