HEADING_CONTACT_US_POPUP_TITLE

HEADING_CONTACT_US_POPUP_SUBTITLE

c1800 Mint Condition Ivory Sector & Protractor Scale Rule
  • c1800 Mint Condition Ivory Sector & Protractor Scale Rule
  • c1800 Mint Condition Ivory Sector & Protractor Scale Rule
  • c1800 Mint Condition Ivory Sector & Protractor Scale Rule
  • c1800 Mint Condition Ivory Sector & Protractor Scale Rule

c1800 Mint Condition Ivory Sector & Protractor Scale Rule

Price:

£150.00


Product Description

A fine English, ivory folding Sector, dating from c1800.

This is very typical of nineteenth century sectors, having scales for inches, decimal feet, lines of sines, tangents, equal parts, chords, numbers (log scales for multiplication), polygons, secants. Sectors were frequently included in sets of drawing instruments in the eighteenth and nineteenth centuries until made obsolete by the slide rule. There are three types of scale on an English sector: sectoral ones (radiating from the hinge centre), which were used for calculation; plane scales (logarithms, sines, tangents) parallel to the edge; and rules (inches, tenths of feet). It is 6 inches folded, 12’’ open, in mint condition. The pivot circle is made of brass and the anchoring pin is intact with a nice tight fit. There are, surprisingly, no maker’s details. The ivory retains a nice cream colour.

Also with the Sector is a mint condition ivory 6 inch Protractor Scale Rule. They were used by mappers, navigators and the military to plot, map or sketch in the field. This protractor has various scales and tables on both sides. Again surprisingly, there are no maker’s details.

Size: 15.3 x 4.2 cm (6 x 1 5/8 inches)
Weight: 46 g

Shipping

  • Shipping Weight: 0.6kgs
  • Worldwide shipping costs can be estimated by adding the item to your basket and clicking the Shipping Estimator.