A sextant measures the altitude of the Sun, Moon, or stars to calculate a position at sea. Sextants were developed in the mid 1700s , from octants, as precision instruments for use in navigating at sea. The were also used by marine surveyors for mapping the coastline and shallow waters.

This particular sextant was made for E. Esdaile, who was a significant retailer of scientific instruments, in Sydney, from 1894 until 1962.

This instrument remains of national significance due to its pioneering role in Australian science and its association with Australia's earliest marine and land surveyors. It is also of significance due to its association with nineteenth century scientific instruments and their makers.

Reference:
J. A. Bennett, The Divided Circle, A history of instruments for astronomy navigation and surveying, Christies Ltd, Oxford, 1987 pg 137

Written by Erika Dicker, Assistant Curator, November 2007.

This sextant was made for E. Esdaile, who was a significant retailer of scientific instruments, in Sydney, from 1894 to 1962.

The firm was founded by William Edward Esdaile (1858/9-1947), who arrived in Sydney with his wife in 1883. At this time, Edward's occupation was listed as Mathematical Surveyor and Telegraphic Instrument Maker. By the time of his arrival in Australia, Edward, who was trained by, and worked for, his father had received a sound knowledge of the instrument making business.

Edward's first job upon arrival in Australia was in the workshops of the Post Master's General, and shortly thereafter he managed the instrument shop for the firm Favelle/Flavelle and Roberts, Sydney. Esdaile left this firm to start his own instrument manufacturing business in 1891. He advertised himself as E. Esdaile, Optician. At this time, Edward was established at 11 Hunter Street, Sydney, in a building known as Parkes House, which was formerly occupied by Sir Henry Parkes.

In 1894, the family took up residence in the city, and rented the residence on the top floor of 54 Hunter Street, which eventually became the firm's first (major) industrial premises. Business expanded rapidly, so the family returned the administrative section to Arncliffe, while the top floors at 54 Hunter Street were converted into instrument-making workshops, and remained there until 1919. One interesting characteristic of the firm's identification was that at this time the 'Sirius' trademark (named after the flag ship of the First Fleet) was adopted and placed on a range of instruments.

The business then moved to 42 Hunter Street in 1919. Esdaile House, as the building was known, was an early reinforced concrete building to be erected in Sydney. The building was erected in 1920 and opened for business. Edward Esdaile was joined in Business by his five sons and in 1924, the firm had changed name to E. Esdaile and Sons.

The Second World War kept the firm busy with orders for surveying equipment, ship's compasses, and gun sights. To keep production abreast of demand, the firm was sufficiently capitalised to employ 60 staff at this time.

When Edward Esdaile died in 1947, an application was made to make Esdailes a public company and was renamed E. Esdaile and Sons Pty Ltd. There was another name change in 1953 to Esdaile (Holdings) Limited. E. Esdaile and Sons Pty Ltd and Esadaile (Holdings) advertised surveying, drafting, scientific and industrial instruments as their core business. The traditional 'Sirius' trademark was retained by the firm.

About 1960, E. Esdailes and Sons (Esdaile Holdings) opened new facilities at 53 Flinders Street, Adelaide. There were three main sections, namely, surveying, scientific and industrial, and drawing office. Surveying included steel tapes, aneroid barometers, abney levels, levelling staves, optical squares, and stereoscopes. Scientific and industrial included anemometers, barographs, thermographs, industrial thermometers, binoculars, and stopwatches, while the drawing office section specialised in drawing instruments, scale rules, set-squares, protractors, T-squares, and drawing boards.

In 1962, Esdaile House was sold to an insurance company and the firm moved to premises at 31 Bay Street, Glebe.

Esdailes were commissioned to undertake important instrument work for a number of science and engineering projects. Edward (Jnr.) was a member of the Sydney Branch of the British Astronomical Association, through which he made contact with Father Edward Francis Pigot (1858-1929), founder and director of Riverview College Observatory, Sydney. Edward's first job for the College was to set up a small telescope at the Observatory, and later he fitted a large astrograph for photographing the stars to the seven-inch refractor telescope that was installed at the Riverview Observatory.

Edward also worked with William Cooke and James Nangle, Government Astronomers for New South Wales, especially in regard to the fitting of the automatic clockwork drive for the large refracting (11 1/2" or the astrograph?) telescope at Sydndey Observatory. In 1952, Edward presented a sun clock to the Observatory, which he made from Cooke's design. This item has been retained for the Museum's collection (H10258).

The firm were engaged for other major engineering projects. Esdailes were commissioned to supply the surveying instruments when the original survey contour maps for Canberra were being prepared. The firm also supplied specialist theodolites for the survey and construction of the Sydney Harbour Bridge, and instruments for measuring the tension in wire (saddle) cables, which held the arch in place during its construction. Finally, the Snowy Mountains Scheme presented many challenges to engineers and surveyors. Esdailes supplied many of the survey instruments for the Scheme. Their instruments were used in ordinary survey work, and in more specialised aspects of surveying including magnetic, and photogrametric surveys. The firm also made instruments for gravimetric analysis.

More generally, Esdailes supplied and repaired surveying instruments to the New South Wales Lands Department, Sydney, established the 'world globe' that once adorned the rooftop on the Ashfield Council Chambers, and manufactured the turnstiles and counter registers for the Sydney Showground and Cricket Ground.

Reference:
Oral history taken from descendants of Edward Esdaile.

This sextant was probably used at Sydney Observatory at sometime between 1896 and 1922.

In 1911 this sextant was tested by the National Physical Laboratory (NPL) at the Kew Observatory in England.

The National Physical Laboratory was established in 1900, by the Royal Society, to carry out research, establish and maintain precise standards of measurements and to test instruments and materials. They also endeavoured to promote links between commerce and science.
The laboratory was situated at the Kew Observatory until 1910. The site was then deemed inappropriate for its intended use at the NPL moved to Bushy park in Teddington, England.

As of 2007, the National Physical Laboratory still develops and maintains the United Kingdom's primary measurement standards and helps ensure accuracy and consistency of scientific measurement throughout the world.

Reference:
http://resource.npl.co.uk/docs/educateexplore/history/history_of_npl.pdf

Navigational equipment, sextant in case, brass / glass / wood, made for E. Esdaile, London, England, 1896-1916, used at Sydney Observatory, New South Wales, Australia, 1896-1922

A brass sextant, no. 9873, 7 1/2" radius, with accessories in polished wooden case. The framework is of blackened brass and shiny brass screws. The scale and vernier are silver and the wooden handles are varnished. There are seven sun filters with telescopes of varying magnification and a magnifying glass for reading the scale and vernier with both mirrors that are fixed. It also has a certificate of examination from National Physical Laboratory, Kew, England attached inside the case.

Observatory number 236.

Made: 1896 - 1916

Retailers and national Physical Laboratory Certificate affixed to the inside lid, On the exterior handle, 'GOV/ OBS' in crown, and '17' etched into wood, also paper label with number ' 236' .
Made for E. Esdaile, 54 Hunter Street Sydney.

The retailers label:
Black print on white paper; "Instrument No / from E. Esdaile / 54 Hunter St Sydney / Maker and Importer of / Surveying, Mathematical and Optical Instruments / Repairs of any kind to any make of Instrument / by experienced workmen".

The certificate:
Black print, and black ink (handwritten) on pale yellow paper: at top is drawing of the National Physics Laboratory. Text " National Physics Laboratory / Kew Observatory, Richmond, Surrey / CERTIFICATE OF EXAMINATION / CLASS A / THE SEXTANT NO 9873 of 71/2 inches radius named / E. Esdaile Sydney N.S.W / divided on silver with vernier showing 10" has been / examined at this institution. The shades and mirrors are good. / The telescopes are also satisfactory and the powers are, for the / inverting 9 and 6 linear, for the erect 3 linear. The following / are the corrections to the readings of the arc (in addition to the index / correction) / August 1911. R. T. Hazelbrook / Director" screwed to the inside lid with brass frame and clear plastic covering.

H10057

1896 - 1916

330 mm

290 mm

400 mm