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H9919 Standard length measure, 40 inch triangular bar, in box with stand, cast iron / gold / wood, maker unknown, made for Captain Henry Kater, England, 1820, used by Sydney Observatory, Sydney, New South Wales, Australia, 1873-1900. Click to enlarge.

Henry Kater’s 40 inch standard bar

Made
Why is this bar triangular, with two gold plugs in it? In 1820 British army officer Captain Henry Kater made precise measurements (to a millionth of an inch) to compare this bar with others, with the aim of creating an official length standard for the British Empire. He chose a triangular rather than flat bar to minimise thermal expansion. He chose gold for the plugs because it is soft and inert, and he used a microscope to position the lines he inscribed on the plugs 40 inches apart.

Philosophical Magazine and Journal, vol 58 no 279,1821, pp 281-298 and pp 335-341.

Debbie Rudder

In the early 1800s, the inconsistency and inaccuracy in measurement standards between Britain and the colony of New South Wales plagued import and export industries. Taxes on the importation of goods were heavily affected by these inaccuracies in measurement. Neither Britain, nor the colony, had a uniform standard of measurement, and weights and lengths were measured differently throughout both countries.

This standard measure was used by Captain Henry Kater in the adjustment of the imperial standard measures of Great Britain. Kater was an English physicist and inventor. In 1814 he was elected a Fellow of the Royal Society of London, where he took a special interest in the design of standard weights and measures. He worked alongside Sir Joseph Banks and Thomas Young to experiment with measures and weights and devise methods of taking accurate measurements

In 1824 Britain streamlined its measurement standards to the use of just three main terms: the imperial yard, the imperial Troy pound, and the gallon. Brass standards were made to represent these measures, and replicas were distributed to the colony. Kater worked closely with London's most significant scientific instrument makers to produce copies of the new imperial standard, which he had helped dictate.

Kater also made a number of contributions to astronomy, including devising a method for graduating circles and inventing the floating collimator. He was also widely acclaimed for his work determining the best kind of steel and form for compass needles.

This standard measurement bar was donated to Sydney Observatory by Henry Kater's son in 1873. The Observatory has a long history of assisting Australia to keep accurate time and accurately measure distances. This standard bar remains of national significance due to its pioneering role in Australian and British science and its association with Australia's earliest surveyors, scientists, and astronomers.

Reference:
Jan Todd, For Good Measure, the making of Australia's measurement system, Allen and Unwin, Australia, 2004 pg 27
http://www.measurement.gov.au/
Holland, J., 'Pioneer of Precision; Captain Henry Kater, FRS', http://www.usyd.edu.au/museums/whatson/exhibitions/kater1.shtml
Macmillan, D. S., The Kater family, 1750-1965, The Kater family?, Sydney, 1966
Holland, J., 'Pioneer of Precision; Captain Henry Kater, FRS', http://www.usyd.edu.au/museums/whatson/exhibitions/kater1.shtml
Lomb, N., 'Earnshaw's Excellent Timekeepers', in Davison, G., Webber, K., 'Yesterday's Tomorrows; the Powerhouse Museum and its precursors 1880-2005', Powerhouse Publishing, 2005
Forwarded to H. M. Secretary of State by Despatch, No. 141, 1847, Federation and Meteorology, http://www.austehc.unimelb.edu.au/fam/1541.html


Written by Erika Dicker
Assistant Curator, November 2007.

Summary

Object No.

H9919

Object Statement

Standard length measure, 40 inch triangular bar, in box with stand, cast iron / gold / wood, maker unknown, made for Captain Henry Kater, England, 1820, used by Sydney Observatory, Sydney, New South Wales, Australia, 1873-1900

Physical Description

A triangular, solid metal, 40 inch line bar stored in a polished timber case with a hinged lid. There is also an associated stand with the line bar. The stand is made up of three pieces, a rectangular metal base that supports two metal cradles.

Production

Notes

There is no makers mark on this standard bar.

History

Notes

This standard measure was used by Captain Henry Kater in the adjustment of the imperial standard measures of Great Britain.

Kater worked along side Sir Joseph Banks and Thomas Young to experiment using measures and weights, and devise methods of taking accurate measurements. Their work significantly influenced the Weights and Measures Act of 1824, which introduced the new British imperial standards for measurements of lengths and weights.

Henry Kater's son, Henry Herman Kater, arrived in Australia in 1839. He had inherited many of his father's possessions after the death of his brother Edward, and this standard bar was one of them. He donated most of these objects to Sydney University and to Sydney Observatory.

This standard bar was presented to Sydney Observatory by Henry Herman Kater in 1873.

Reference:
Macmillan, D. S., The Kater family, 1750-1965, The Kater family?, Sydney, 1966
Holland, J., 'Pioneer of Precision; Captain Henry Kater, FRS', http://www.usyd.edu.au/museums/whatson/exhibitions/kater1.shtml
Lomb, N., 'Earnshaw's Excellent Timekeepers', in Davison, G., Webber, K., 'Yesterday's Tomorrows; the Powerhouse Museum and its precursors 1880-2005', Powerhouse Publishing, 2005
Forwarded to H. M. Secretary of State by Despatch, No. 141, 1847, Federation and Meteorology, http://www.austehc.unimelb.edu.au/fam/1541.html

Cite this Object

Harvard

Henry Kater's 40 inch standard bar 2020, Museum of Applied Arts & Sciences, accessed 27 September 2020, <https://ma.as/259027>

Wikipedia

{{cite web |url=https://ma.as/259027 |title=Henry Kater's 40 inch standard bar |author=Museum of Applied Arts & Sciences |access-date=27 September 2020 |publisher=Museum of Applied Arts & Sciences, Australia}}
This object is currently on display in Collection Gallery 4 at the Museums Discovery Centre.

Incomplete

This object record is currently incomplete. Other information may exist in a non-digital form. The Museum continues to update and add new research to collection records.