Renseignements généraux

Nº de série

S/O

Nº de partie

1

Nombre total de parties

1

Ou

S/O

Brevets

S/O

Description générale

Mahogany octant has boxwood scale; brass & glass fittings, ivory inset in frame & over scale/ mahogany (?) case

Dimensions

Remarque : Cette information reflète la taille générale pour l’entreposage et ne représente pas nécessairement les véritables dimensions de l’objet.

Longueur

52,0 cm

Largeur

47,8 cm

Hauteur

9,1 cm

Épaisseur

S/O

Poids

S/O

Diamètre

S/O

Volume

S/O

Lexique

Groupe

Exploration et levé

Catégorie

Mesure-angle

Sous-catégorie

S/O

Fabricant

Ou

Cole

Pays

England

État/province

Inconnu

Ville

London

Contexte

Pays

Worldwide

État/province

Inconnu

Période

Probably used c. 1760-1850

Canada

Unknown. G.C. Morrison, Glenholme Nova Scotia is written in pencil on the inside of the cover. Manufactured by Benjamin Cole Jr., of London. Bought from Christie's Auction.

Fonction

To determine latitude, by measuring the altitude of heavenly bodies above the horizon. Large radius octant. Navigators at sea could determine latitude and longitude by measuring the angle between celestial objects and the horizon line. This angle was measured by adjusting the scale until the celestial object appeared to touch the horizon line in a mirror.

Technique

Example of large radius octant with transversal type scale. It represents quality instrument, made by well-known mfr., in transition period between large radius octants divided by hand & those divided by machine & of small radius (ref.1).superseded in 1770s by more accurate sextant, octant made & used c.1900 because it was less expensive to produce (ref.3, p.264). Double "pin-hole" sight and back sight. Example of large radius octant with a transversal type scale. Numbers are on both sides of the scale and go from 0? to 90? on one side in 2 minute intervals and the opposite direction on the other side in 20 minute intervals. It represents a quality instrument in the transition period between large radius octants divided by hand and those divided by ruling engines.

Notes sur la région

Inconnu

Détails

Marques

'COLE Maker/ Fleet Street/ LONDON' INCISED & HIGHLIGHTED IN BLACK ON LEFT END OF SCALE ON ARC. SCALE DIVIDED 0-90 BY 2-MINUTE INTERVALS ON TOP EDGE; 90-0 BY 20-MINUTE INTERVALS ON LOWER EDGE/ 'G C Morrison/ Glenholm/ N.S.' HANDWRITTEN IN PENCIL ON INSIDE OF CASE LID/ CHRISTIE'S LABEL ON LOWER FRONT EDGE OF CASE READS: '312/ 8 JUNE 1992'.

Manque

None

Fini

Inconnu

Décoration

S/O