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Ivory Sector

Technical Information

Catalogue No: C1716
Category: Vintage and Antique
Object Type: Indicator/Instrument
Object Name: Ivory Sector
Part No: None
Serial No: None
Manufacturer: Elliott Bros (London) Ltd
Year of Manufacture: Unknown
Dimensions: Width (mm): 160
Height (mm): 3
Depth (mm): 35
Weight (g): 41
Location: Cupboard CG (Display 2) [Main Store]



An ivory sector by Elliott Bros, Strand, London dating from between 1854 and 1880. 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. It is a six-inch size example.
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).

The Sector was acquired with the Collection of the late Ron Howard (A similar version can be seen in the Elliott Collection at The Museum of the History of Science in Oxford)

The Ron Howard Archive and Collection

The centre of the archive is contained in fifteen chronological ring binder files (1951 - 1993), containing photographs, programmes, news clippings, technical papers and correspondence chronicling the history of Elliott Brothers and the subsequent constituent companies of Marconi and GEC. They record Ron Howard's involvement with the development of, among others, the VC-10, Boeing 747 and Concorde, with an emphasis on automatic flight controls systems, one of his key areas of interest.  The material was sent by  the family of the late Ron Howard and received by the RAA in 2019. A description of the items and a short biography of Ron Howard can be seen in Document D0618


The Collection has a number of quite early scientific instruments and some personal items 

RAA Catalogue No. and Description

Verners Pattern Prismatic Compass VIII. Elliott Compass in Leather case

Colonel William Willoughby Cole Verner was born in 1852 and commissioned into The Rifle Brigade in 1874, retiring in 1904. He served on the staff in the Egyptian campaign of 1884-85 and during the Boer War. He died in 1922. This is a Verner Cavalry Sketch Board, by Elliott Brothers, London, c.1887

Ivory rectangular (4 1/2”) Protractor (top) made by Elliott Bros.C1716
A six-inch ivory sector dating from between 1854 and 1880 made by Elliott Bros.
A Telescope. No makers name can be seen.
A Galvanometer made by Elliott Bros London
A set of Draughting Instruments in a case made by Elliott Bros
A compass manufactured by Elliott Brothers between 1854 and 1865. #228 has a Gold spindle.
A compass manufactured by Elliott Brothers between 1854 and 1865. This one  has no serial No. but has a silver spindle and is marked L.F.Heath
Elliott Desk ornament.
SBAC Past President Badge
An Aneroid Barometer with its leather case. The double ended pocket Aneroid Barometer is signed by John Henry Steward. It has a leather case.
An Aneroid Barometer calibrated in ins Hg and Feet as an Altimeter There is no makers name. It has a gold case and a leather case.
Airspeed Indicator
Ron Howard's personal Flying Helmet with Oxygen mask and Goggles.

 A Telegraph Lineman's Galvanometer (circa 1910?) made by the India Rubber, Gutta Percha and Telegraph Works Co at Telegraph Works Silvertown, London

An Abney Level with Protractor and Spirit Level used in surveying
An Aneroid Barometer with the  dial  marked 'Compensated' and is calibrated from 15 to 31 inches of HG and 0 to 20,000feet.The case was made by J.B.Brooks
Thomas Parnell (fl. 1784-1811) was a mathematical and nautical instrument maker in London. This is a Spring Balance in a case.
Desk clock and Pen stand
Barometer in Silver case with no markings. The Barometer has a hard leather case.
Gunnery instrument, for adjusting the angle of the barrel
A Barometer/Weather Finder
Sand Timer. No makers name can be seen. A 14 second ships log timer.

A Spring Scale calibrated in Lbs made by George Salter & Co
A set of Draughting Instruments in a case by Charles Baker of 544 High Holborn est 1765.
Possibly part of another instrument and has a small optics
A Button Hook and Leather stitch marking tool.
A Marching  Compass Mk1 with a black bakelite case.  T.G & Co Ltd
Probably an Award

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