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Sector, by Thomas Heath, London, c. 1730

preview image for Sector, by Thomas Heath, London, c. 1730
Inventory Number: 36704
Object Type:
Persons: Thomas Heath
Date Created:
Place Created: London England United Kingdom Europe
Accession Number:
Brief Description: Brass sector on 12 inch radius and with extensive decoration.

The layout of scales is not identical to those on the other numbered Heath sector (inv. 49772); the pattern is closer to sectors by Culpeper (inv. 50251 for example). On the signature side is a mixture of sequential and symmetrical sectoral scales. The sequential scales are chords Cho (0-60) and equal parts Lin (0-10). Arranged symmetrically between them are secants Sec (10-75) and over the gap between the two legs on this side is a sectoral line of polygons POL (12-6). Against the edges are continuous scales for use with the sector fully opened: artificial tangents Tan (-45), artificial versed sines V. Sin (168-0), artificial sines Sin (-90) and a double scale of artificial numbers (logarithms) Num repeating just before the hinge.

The scales on the reverse also include a mixed arrangement of sequential and symmetrical sectoral scales.Sequential are sines Sin (0-90) and tangents Tan (0-45). In between are symmetrical tangents tan (45-75). There are two pairs of natural scales: inclination of meridian In-Mer (0-90) and latitude Lat. (0-90), and chords Cho. (0-90) and Hour. (0-VI). The continuous scales for use with the sector fully opened are: inches (0-24) and equal parts (0-200).
Primary Inscriptions: Engraved "Tho: Heath Fecit" and "No. 38"
Provenance:
Collection Group:

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