This clinometer, or Abney's reflecting level, is a hand-held optical scientific instrument used in surveying to measure vertical angles. It has a leather case which is inscribed "Major David Australian Mining Corps Clinometer".

The clinometer was owned and used by Professor Edgeworth David (1858-1934), a geologist from The University of Sydney who in 1915 was involved in the formation of the Australian Mining Corps. In 1916 Professor David went to the Western Front with the 1st Australian Tunnelling Company. Probably the most important role undertaken by David during the War was the geological work involved in sinking shafts and boring tunnels well under the German lines at Messines Ridge, near Ypres, Belgium, in the Hill 60 area. This was one of the most famous locations on the Western Front, as its strategic position was continually fought over on both sides.

Several tunnels penetrating under the German lines, extending some 1400 feet, were started by the British and Canadians but taken over by the 1st Australian Tunnelling Company under Major J. Douglas Henry in November 1916. These were packed with explosives and on 7 July 1917, a series of 19 explosions destroyed 19 German strongholds and killed 50,000 men. This was dramatically illustrated in the 2010 Australian film "Beneath Hill 60".

The instrument is basically a long rectangular miniature telescope on the side of which is mounted a semi-circular arc, graduated in degrees for measuring vertical angles, and a small spirit level. While looking through the telescope at any angle, a mirror reflection of the spirit bubble could be viewed through a small window to line up the horizontal or determine an angle of inclination.

This Abney level may also have been used on Ernest Shackleton's British Antarctic Expedition of 1907-1909, of which Professor David was a member. In Shackleton's book "The Heart of the Antarctic" published in 1909 he referred to unusual polar clouds observed from the "Nimrod" on the voyage down. He noted that the height of these was determined by Professor David and Leo Cotton with an Abney level and sextant. The Abney level was donated to the Museum by a grandson of Leo Cotton.

Margaret Simpson
Curator, Science, Technology & Industry
January 2012

Branagan, Professor David, "The Australian Mining Corps in World War I", at Mineral Heritage Luncheon, Annual Conference of the Institute, Newcastle, NSW, 1987.

http://www.opticaliamuseum.com/surveying/hand-table-staff-mount-instruments/

'Literature Book of the Week' in "The Advertiser" (Adelaide), 4 December 1909, p.17.

http://www.compassmuseum.com/geo/geo_3.htm

The Abney level or miniature theodolite was invented in the 1870s by Sir William de Wiveleslie Abney (1843-1920) an English astronomer and chemist known for pioneering colour photography. It was developed during Sir William's employment at the School of Military Engineering in Chatham, England.

The instrument was simply a type of sextant for measuring vertical angles on land, not using the sun. Until its invention clinometers were either very bulky (sextants were used) or were not very accurate. Abney invented this pocket size level purely to fill a much needed gap in the market. Surveyors welcomed his invention, but it was primarily used by the military for artillery and engineering purposes such as road and bridge building.

This Abney level had been made by 1916 by the English firm of Negretti & Zambra, of 38 Holborn Viaduct, London. This firm was established in 1850 by Henry Negretti (1818-1879) and Joseph Zambra (1822-1897). When the Crystal Palace building was moved to Sydenham in 1854 they became the official photographers and went on to be opticians and scientific instrument makers. By the 1880s they were making all types of scientific instruments including deep sea thermometers, prismatic compasses, telescopes and pocket barometers.

This Abney level was used by the Australian geologist Tannatt William Edgeworth David (1858-1934). Born in Wales, David arrived in Sydney in 1882 as an assistant geological surveyor on the NSW Geological Survey. He went on to map the coal measures on the South Maitland coal field from Greta to Cessnock and along the Newcastle coast.

In December 1907 Professor David together with his former students, Douglas Mawson and Leo Cotton, joined Ernest ShackletonÂ?s British Antarctic expedition. David led a party including Mawson who were the first to climb the active volcano, Mt Erebus, 3794 metres high. On the same expedition David, Mawson and Alistair Forbes McKay made a heroic 4-month journey to the South Magnetic Pole.

In 1916 David was involved in the formation of the Australian Mining Corps during World War I. Geologists were extremely important during this war as armies became literally bogged down in trench warfare. Knowledge of geology was very useful for both defensive and offensive purposes. It helped to determine where to construct dugouts, dig tunnels under the lines, and find drinking water. Geology and mining played a pivotal role in Eastern France and Belgium and the Germans were acutely aware of their importance, having some 100 geologists employed whereas the allies initially only had two, David and Captain W.B. King. At the age of 58 David secured a commission as a major.

Probably the most important role undertaken by David during the War was the geological work involved in sinking shafts and boring tunnels well under the German lines at Messines Ridge, near Ypres, Belgium, in the Hill 60 area. This was one of the most famous positions on the Western Front as its strategic position was continually fought over on both sides. Several tunnels penetrated under the German lines, extending some 1400 feet were started by the British and Canadians but taken over by the 1st Australian Tunnelling Company under Major J. Douglas Henry in November 1916. These were packed with explosives and on the 7 July, 1917, a series of 19 explosions destroyed 19 German strongholds and killed 50,000 men.

A clinometer would have been important to geologists such as David for determining the degree of slope in the mining tunnels, especially for drainage.

David's Abney level eventually came into the Cotton family. Leo Cotton had been a student of David's at The University of Sydney and succeeded David as Professor of Geology in 1925. In 1947 Cotton wrote an unpublished biography of David. This Abney level, as well as several other scientific instruments and photography equipment belonging to Leo Cotton were handed down the Cotton family line and donated to the Museum by Leo Cotton's grandson, Malcolm Cotton.

Clinometer with case, 'Abney's reflecting level', metal / leather, made by Negretti & Zambra, London, England, used by Tannatt William Edgeworth David, France and Belgium, 1916-1917

A clinometer is also known as an Abney level. It is a hand-held scientific instrument used for measuring vertical angles. It comprises a rectangular sighting tube with an eye piece at the near end and an Abney reflecting level at the far end. The level constitutes a semi-circular arc divided to show gradients mounted on the rectangular tube. A moveable bubble level is also fixed to the arc.

According to the "McGraw Hill Encyclopaedia of Science and Technology" a 45-degree mirror inside the tube enabled the observer to see the bubble at the same time that the observer sighted a point or a graduated rod with a horizontal wire. Manipulation of the vertical arc brought the bubble to the centre in coincidence with the sighted point. The vertical angle was indicated on the arc.

The clinometer has a leather case with stitching. The case is inscribed "Major David Australian Mining Corps Clinometer".

Made: 1910 - 1920

2012/38/4

1910 - 1920