A heavy cardboard burgandy coloured cover with gold information on the front. At the top of the manual reads Ordnance Proof Manual with an insignia under this. The rest of the information in under the insignia. The manual cover has a metal hinge front and back. The are three metal screws both on the front and back of the manual.united states - armed forces - service manuals, ordnance, ordnance proof, instrumentation, united states government

This is a set of 16 photograph of the Royal Australian Survey Corps’ Johnson Ground Elevation Meter (JGEM) Survey Vehicle taken at the Army Survey Regiment, Fortuna, Bendigo. The JGEM vehicle was extensively used by RA Svy within Australia from the late 1960s. A limited number of Ground Elevation Meter (GEM) station wagon type vehicles were manufactured by General Motors Corporation (GMC) in the USA for the United States Geological Survey, Canada’s mapping agencies, RA Svy and National Mapping (Natmap). The GEM was a four-wheel drive, four-wheel steer vehicle. Four-wheel steering was necessary to avoid systematic errors caused by non-tracking of front and rear wheels on conventionally steered vehicles. The manufacturer substituted the rear axle with a front axle and connected them to form the four-wheel steering mechanism. The two Australian GEM vehicles, referred to as Johnson GEMs (JGEMs) were converted into right-hand drive. After delivery in 1964, acceptance Natmap and RA Svy testing and operator training was undertaken at the Army's School of Military Survey located at Balcombe, Victoria. A small fifth wheel was mounted on a cantilever arm suspension midway between the front and rear wheels on the right side of the vehicle. It was lowered to and raised from its operating position by use of a constant pressure air cylinder. A telescopic bar, suspended between the front and rear axles, provided the reference datum for the angle measurement. The wheel provided the velocity or distance signal through a pulse generator system. A sensitive pendulum mounted on this bar provided the angle measurement for each minute distance traversed. The JGEM contained electromechanical instruments used to determine relative elevations, by trigonometric principles, along a traversed path. These relative elevations were obtained through apparatus which measures the instantaneous angle of inclination of the road and the instantaneous velocity of the meter along such a path. Road routes over which the JGEM operated were planned so that each started and ended as near as practicable to an existing point of known elevation (formally referred to as a level traverse bench mark). The difference in height from the bench mark and the road surface alongside the JGEM’s fifth wheel was measured with a level and staff. Along each route, mapping control photo reference points where new elevation values were required were identified on aerial photographs. Under favourable conditions it was possible to survey as much as 160km in an ordinary working day. The first of RA Svy’s JGEM operations was undertaken in 1:250,000 scale map areas of Queensland. CPL John Hook was the JGEM’s main operator in the early 1970s undertaking operations covering 1:250,000 scale map blocks over northern Victoria and central NSW, each requiring 36 points (9 runs of photography and 4 points across. SPR Lyn Thompson and SPR Bob McDonagh teamed with CPL Hook on some of these JGEM operations. When RA Svy was integrated into the Royal Australian Engineers in 1996, the JGEM vehicle with the Survey Corps collection was donated to its museum. It is believed to be the last of the original manufactured fleet in existence. The JGEM has undergone extensive refurbishment to achieve roadworthiness and is currently housed at The Australian Army Museum of Military Engineering, Hoslworthy Barracks, NSW. It can be viewed by making an appointment with the museum’s curator.This is a set of 16 photograph of the Royal Australian Survey Corps’ Johnson Ground Elevation Meter (JGEM) Survey Vehicle taken at the Army Survey Regiment, Fortuna, Bendigo. The photographs were on 35mm slide film and were scanned at 96 dpi. They are part of the Army Survey Regiment’s Collection. .1) - Photo, colour, c1960s, Johnson Ground Elevation Meter (JGEM) Survey Vehicle .2) - Photo, colour, c1960s, JGEM instrumentation, on-board computer. .3) - Photo, colour, c1960s, JGEM instrumentation. .4) - Photo, colour, c1960s, JGEM instrumentation, on-board computer. .5) - Photo, colour, c1960s, JGEM tyre pressure controller .6) - Photo, colour, c1960s, JGEM rear doors, SGT Geoff Briggs. .7) - Photo, colour, c1960s, JGEM 5th wheel distance/angle measurement device in lowered position, SGT Geoff Briggs. .8) - Photo, colour, c1960s, JGEM 5th wheel distance/angle measurement device in lowered position. .9) & .10) - Photo, colour, c1960s, JGEM tyre pressure system, SGT Geoff Briggs. .11) - Photo, colour, c1960s, JGEM tyre pressure system. SGT Geoff Briggs. .12) - Photo, colour, c1960s, JGEM levelling scope, levelling staff, unidentified technicians. .13) & .14) - Photo, colour, c1960s, JGEM levelling scope, unidentified technician. .15) & .16) - Photo, colour, c1960s, probably survey operation adjusted height plotted on block base sheet. .1P to .16P - Some of the equipment is annotated on the frame of the 35mm slides.royal australian survey corps, rasvy, army survey regiment, army svy regt, fortuna, asr, surveying

On reverse: Four stage solid fuel Scout vehicle and cross section of payload instrumentation. First solid fuel rocket used by N.A.S.A. to launch a satellite on orbital trajectory. Front cap comes off and satellite built of tghin mylar plastic film and aluminium foil emerges and inflates. Radio beacon built in for tracking.alan gardiner collection, space industry, 1960, nasa, rocket, scout solid fuel rocket

Victorian Institute of Occupational Safety and Health (VIOSH) Australia is the Asia-Pacific centre for teaching and research in occupational health and safety (OHS) and is known as one of Australia's leaders on the field. VIOSH has a global reputation for its innovative approach within the field of OHS management. VIOSH had its first intake of students in 1979. At that time the Institution was known as the Ballarat College of Advanced Education. In 1990 it became known as Ballarat University College, then in 1994 as University of Ballarat. It was 2014 that it became Federation University. VIOSH Australia students are safety managers, senior advisors and experienced OHS professionals. They come from all over Australia and industry. Students are taught active research and enquiry; rather than textbook learning and a one-size fits all approach. VIOSH accepts people into the Graduate Diploma of Occupational Hazard Management who have no undergraduate degree - on the basis of extensive work experience and knowledge. Instrument used to determine the humidity in a location. Made in England by Brannan. Established in 1913, Brannan are a global manufacturer of thermometers, pressure gauges & associated instrumentation productsBrown leather case with brass clip. Wooden frame with thermometer tubes. Black handle used to swing meter around. Gauge for temperature scale Made in England. Brannanviosh, victorian institute of occupational safety and health, brannan, england, thermometers, pressure gauges, humidity hydrometer

Long term loan from Neurological Society of Australasia Museum of Neurosurgical Instruments,South Australia. Catalogue with Historical Commentaries Second Edition January 2006 Copy located at RACS MuseumTrumble's Skull Plough or craniotome devised by Hugh Trumble (1864-1962 ) CRANIOTOME. This craniotome was designed by Hugh Trumble (1894-1962) of the Alfred Hospital, Melbourne, one of the eight founders of the Neurosurgical Society of Australasia. It was a modification of an earlier instrument, similar in principle but less versatile, designed by Sir Henry Souttar(l875 - 1964), a very inventive surgeon who worked in the London Hospital. Souttar also used a motor-powered circular saw when necessary. He cut very large circular bone flaps, exposing the occipital lobes and posterior fossa in a few minutes. Trumble reported the use of this craniotome as "an expeditious method of cutting bone flaps" and in the designer's hands this claim was certainly justified. To use the crauiotome, it was necessary to hold the skull rigidly, and this was done by embedding the head in a plaster mould. Three holes were drilled in the skull to fix the pin of the craniotome, and the flap was then cut in a series of three arcs, after which the flap was elevated with levers until its base fractured. The 'Trumbolian" instrumentation was used in the Alfred Hospital by a number of Trumble's pupils. The craniotome is made of steel, not plated and apparently not stainless. It is believed that Trumble made his craniotomes himself, in a backyard workshop.

The theodolite was sold by T. Gaunt & Co. of Melbourne, a manufacturer, importer and retailer of a wide variety of goods including jewellery, clocks and watches, navigational and measuring instruments, dinnerware, glassware and ornaments. Thomas Gaunt photograph was included in an album of security identity portraits of members of the Victorian Court, Centennial International Exhibition, Melbourne, 1888. (See further details below.) History for Troughton & Simms: Edward Troughton & William Simms established a scientific instrument making business in London in 1826. Edward Troughton (1756-1835) had previously had his own scientific instrument business, inherited from his father. His achievement's included a transit telescope for Greenwich Observatory (1816) and the precision surveying instruments for the Ordnance Survey of Britain, Ireland and India. William Simms (1793-1860) had trained as a goldsmith and began to gain work dividing circles on fine astronomical instruments. When William Simms died in 1860, the business was taken over by his son James and nephew William. Troughton & Simms shop in Fleet Street became the hub of the finest scientific instrument made in London, in a period in which there was an expanding demand for precision instruments, for astronomy, surveying and precision measurement. They made instruments for Greenwich Observatory, for imperial surveys and exploring expeditions. When fire destroyed the Houses of Parliament in 1834, the firm was commissioned to create new standard lengths, this required 10 years of testing against the remaining old measurements. Troughton and Simms made several of the main instruments for Melbourne Observatory, including an 18 inch azimuth used of the Geodetic Survey, portable transit instrument (circa 1850), zenith sector (1860), a 4.5 inch equatorial telescope (1862), an 8 inch equatorial telescope (1874) spectroscope (1877) and an 8 inch transit instrument in (1884). While the firm had an excellent reputation for quality the company exasperated many of its customers with delays of years in delivering some instruments. History for Thomas Gaunt: Thomas Ambrose Gaunt (1829 – 1890) was a jeweller, clock maker, and manufacturer of scientific instruments, whose head office and showroom were at 337–339 Bourke Street, Melbourne, Victoria, Australia. Thomas Gaunt established Melbourne's leading watchmaking, optical and jewellery business during the second half of the 19th century. Gaunt arrived in Melbourne in 1852, and by 1858 had established his own business at 14 Little Bourke Street. Around 1869 he moved to new premises in Bourke Street on the corner of Royal Arcade, Gaunt's shop quickly became a Melbourne institution. Gaunt proudly advertised that he was 'The only watch manufacturer in the Australian colonies'. While many watches and clocks may have had Gaunt's name on the dial, few would have been made locally. Gaunt did make some watches for exhibitions, and perhaps a few expensive watches for wealthy individuals. Gaunt's received a telegraph signal from Melbourne Observatory each day to correct his main clock and used this signal to rate and repair ship's chronometers and good quality watches. Thomas Gaunt also developed a department that focused on scientific instrumentation, making thermometers and barometers (from imported glass tubes), telescopes, surveying instruments and microscopes. Significance: With the rapid urban expansion, one of the most important needs of the new colony was to survey and map the landscape of the Australian Colony’s interior. Theodolites, such as this one, made by Troughton and Simms, who were significant scientific instrument makers of the 19th century were instrumental to the colony's surveyors and would have played an important part in their everyday work. This transit theodolite remains of national significance due to its pioneering role in Australian science and its association with Australia's earliest surveyors and astronomers. It is also significant for its association with nineteenth-century surveying instruments and instrument makers. Theodolite, Vernier repetition theodolite with enclosed horizontal circle (of about 130 mm diameter). Vertical circle exposed and somewhat corroded (diameter about 115 mm). Plate level 20" per division. Altitude bubble 20" per division. Horizontal and vertical circle intervals 20". Original (blue/grey) paint. Altitude bubble setting screw disabled. Tribrach allows movement of theodolite by 15 mm inside tribrach (for centering).Inscribed on the inner mounting plate,“Specially made in England for T Gaunt & Co Melbourne” and inscribed a little lower “Troughton & Simms London”flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, theodolite, t. gaunt & co, troughton & simms, scientific instrument, measuring instrument, surveyor's instrument

The barometer was either made or sold by T. Gaunt & Co. of Melbourne, a manufacturer, importer and retailer of a wide variety of goods including jewellery, clocks and watches, navigational and measuring instruments, dinnerware, glassware and ornaments. Thomas Gaunt photograph was included in an album of security identity portraits of members of the Victorian Court, Centennial International Exhibition, Melbourne, 1888. (See below for further details.) Admiral Fitzroy Pattern Barometer History: The stick mercury barometer was named after Admiral Robert Fitzroy of the Royal Navy (1805-1865) for his detailed instructions on how to interpret the weather, which were included with the instrument. Fitzroy was the captain of the HMS Beagle, also a weather forecaster to Charles Darwin and the second Governor of New Zealand. He developed many different types of barometers and was the first person to introduce the science of weather forecasting to the British Isles. A local manufacturer of scientific instruments, Thomas Gaunt, produced the barometer that was adapted for the southern hemisphere by Robert Ellery, the State Astronomer based at the Melbourne Observatory. In the original sale catalogue for Gaunt's, the item is described as "Gaunt's Fitzroy Barometers" and it was priced from 25/- to ₤9.9s. History of Thomas Gaunt: Thomas Gaunt established Melbourne's leading watchmaking, optical and jewellery business during the second half of the 19th century. Gaunt arrived in Melbourne in 1852, and by 1858 had established his own business at 14 Little Bourke Street. Around 1869 he moved to new premises in Bourke Street on the corner of Royal Arcade. Gaunt's shop quickly became a Melbourne institution. Gaunt proudly advertised that he was 'The only watch manufacturer in the Australian colonies'. While many watches and clocks may have had Gaunt's name on the dial, few would have been made locally. Gaunt did make some watches for exhibitions, and perhaps a few expensive watches for wealthy individuals. Gaunt's received a telegraph signal from Melbourne Observatory each day to correct his main clock and used this signal to rate and repair ship's chronometers and good quality watches. His main horological manufacturing was directed at turret clocks for town halls, churches and post offices. These tended to be specific commissions requiring individualised design and construction. He made the clock for the Melbourne Post Office lobby, to a design by Government Astronomer Robert Ellery, and won an award at the 1880-81 Melbourne International Exhibition for his turret clock for the Emerald Hill Town Hall. He became well known for his installation of a chronograph at Flemington Racecourse in 1876, which showed the time for the race, accurate to a quarter of a second. The firm also installed the clockwork and figures for Gog and Magog in the Royal Arcade. Thomas Gaunt also developed a department that focused on scientific instrumentation, making thermometers and barometers (from imported glass tubes), telescopes, surveying instruments and microscopes. Another department specialised in electroplating for trophies, awards and silverware, and the firm manufactured large amounts of ecclesiastical gold ware and silverware, for the church including St Patrick's Cathedral. There are no records that disclose the number of employees in the firm, but it was large enough for Gaunt to hold an annual picnic for the watchmakers and apprentices at Mordialloc from 1876; two years previously they had successfully lobbied Gaunt to win the eight hour day. Gaunt's workforce was reportedly very stable, with many workers remaining in the business for 15 to 30 years. Gaunt's wife Jane died on September 1894, aged 64. They had one son and six daughters, but only three daughters survived to adulthood. Two became nuns at the Abbotsford Convent and one daughter, Cecelia Mary Gaunt (died 28 July 1941), married William Stanislaus Spillane on 22 September 1886 and had a large family. Gaunt died at his home in Coburg, Victoria, leaving an estate valued at ₤41,453. The business continued as T. Gaunt & Co. after his death. The barometer is historically significant as an example of the work of Melbourne’s leading scientific instrument maker, Thomas Gaunt. The barometer has social significance as an example of the type of scientific equipment that Thomas Gaunt expanded his horology business into producing. Further social significance lies in the fact that Robert Ellery, the Government Astronomer who designed the local version of the barometer, had a direct connection with the Melbourne Athenaeum founded in 1839 as the Melbourne Mechanics' Institution. Its purpose was "the diffusion of literary, scientific and other useful information". There are also records of a T Gaunt as a subscription and committee member of this the Athenaeum organisation during the 1870s and 1880s which may be Thomas Gaunt, unfortunately still unverified.Stick mercury barometer known as the Admiral Fitzroy Barometer. It comprises an oblong wooden case with glass front panel, ornate pediment, barometer with bulb cistern (empty of fluid), cleaning brush with printed instructions for interpreting information given by the gauge affixed to left and right face of instrument. Includes a thermometer. The barometer appears to be intact. Adapted to the Southern Hemisphere. Special remarks by Admiral Fitzroy. Made by Thomas Gaunt, Melbourne. Manufacturer's details are on back of wooden casing. Rear has upper and lower brass screw plates for securing to vertical surface."Manufactured by Thomas Gaunt, 14 Little Bourke Street, Melbourne. "flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, barometer, admiral fitzroy, thomas gaunt, thomas gaunt of melbourne, clockmaker, admiral fitzroy barometer, barometer instructions, gaunt’s fitzroy barometer, gaunt’s of melbourne, gog and magog designer, horological manufacturer, meteorological instrument, melbourne athenaeum, melbourne mechanics' institution, melbourne observatory time signal, robert ellery government astronomer, scientific instrument, stick mercury barometer, thermometer, weather forecast, t gaunt & co

The clock was either made or sold by T. Gaunt & Co. of Melbourne, a manufacturer, importer and retailer of a wide variety of goods including jewellery, clocks and watches, navigational and measuring instruments, dinnerware, glassware and ornaments. Thomas Gaunt photograph was included in an album of security identity portraits of members of the Victorian Court, Centennial International Exhibition, Melbourne, 1888. Thomas Gaunt History: Thomas Gaunt established Melbourne's leading watchmaking, optical and jewellery business during the second half of the 19th century. Gaunt arrived in Melbourne in 1852, and by 1858 had established his own business at 14 Little Bourke Street. Around 1869 he moved to new premises in Bourke Street on the corner of Royal Arcade, Gaunt's shop quickly became a Melbourne institution. Gaunt proudly advertised that he was 'The only watch manufacturer in the Australian colonies'. While many watches and clocks may have had Gaunt's name on the dial, few would have been made locally. Gaunt did make some watches for exhibitions, and perhaps a few expensive watches for wealthy individuals. Gaunt's received a telegraph signal from Melbourne Observatory each day to correct his main clock and used this signal to rate and repair ship's chronometers and good quality watches. His main horological manufacturing was directed at turret clocks for town halls, churches and post offices. These tended to be specific commissions requiring individualised design and construction. He made the clock for the Melbourne Post Office lobby, to a design by Government Astronomer Robert Ellery, and won an award at the 1880-81 Melbourne International Exhibition for his turret clock for the Emerald Hill Town Hall. He became well known for his installation of a chronograph at Flemington Racecourse in 1876, which showed the time for the race, accurate to a quarter of a second. The firm also installed the clockwork and figures for Gog and Magog in the Royal Arcade. Thomas Gaunt also developed a department that focused on scientific instrumentation, making thermometers and barometers (from imported glass tubes), telescopes, surveying instruments and microscopes. Another department specialised in electroplating for trophies, awards and silverware, and the firm manufactured large amounts of ecclesiastical gold ware and silverware, for the church including St Patrick's Cathedral. There are no records that disclose the number of employees in the firm, but it was large enough for Gaunt to hold an annual picnic for the watchmakers and apprentices at Mordialloc from 1876; two years previously they had successfully lobbied Gaunt to win the eight hour day. Gaunt's workforce was reportedly very stable, with many workers remaining in the business for 15 to 30 years. Gaunt's wife Jane died on September 1894, aged 64. They had one son and six daughters, but only three daughters survived to adulthood. Two became nuns at the Abbotsford Convent and one daughter, Cecelia Mary Gaunt (died 28 July 1941), married William Stanislaus Spillane on 22 September 1886 and had a large family. Gaunt died at his home in Coburg, Victoria, leaving an estate valued at ₤41,453. The business continued as T. Gaunt & Co. after his death. Post Office and Clock History: Warrnambool’s Post Office has been in existence since 1857, when it was originally situated on the corner of Timor and Gilles Street. In March 1864 the Warrnambool Borough Council purchased this clock from Henry Walsh Jnr. for the sum of £25, “to be put up in front of the Post Office”. Henry Walsh Jnr was the eldest son of Melbourne’s Henry Walsh, maker and retailer of clocks, watches, thermometers and jewellery. In 1854 Henry Walsh Jnr. began business in Warrnambool as a watchmaker and jeweller later becoming a Councillor with now a local street named after him. The Post Office was extensively remodelled in 1875-76. Early photographs of this building show that the clock was installed on the northern outside wall, Timor Street, under the arches and between the 2 centre windows, where it could be seen by passers-by. Although spring loaded clocks date back to the 15th century, and fob and pocket watches evolving from these date to the 17th century, personal pocket watches were only affordable to the very fortunate. Public clocks such as this Post Office clock provided opportunity for all to know the time, and for those in possession of a personal watch to check and set their own timepieces to the correct time. During post office reservations during the 1970s the clock was removed and was eventually donated to the Flagstaff Collection. The Clock’s maker Thomas Gaunt, is historically significant and was an established and well renowned scientific instrument and clock maker in Melbourne during the 1860s. He was at that time the only watchmaker in the Australian colonies. In the 1870’s and 1880’s he won many awards for his clocks and was responsible for sending time signals to other clocks in the city and rural areas, enabling many businesses and organisations to accurate set their clocks each day. Warrnambool Borough Council purchased this clock from Henry Walsh Jnr. for the sum of £25 and the clock used to stand in front of the Warrnambool post office to allow ordinary citizens to set their time pieces as they walked by. The item is not only important because it was made by a significant early colonial clock maker and retailed by a locally known clock maker and jeweler but also that it was installed in the Warrnambool Post Office a significantly historical building in it's own right. Built in 1857 and regarded as one of the oldest postal facilities in Australia, with a listing on the National Heritage Database, (ID 15656). This 1864 hall clock originates from the Warrnambool Post Office. The clock glass is hinged to the top of the clock face and has a catch at the bottom. The metal rim of the glass is painted black. The clock face is metal, painted white, with black Roman numerals and markings for minutes and five minutes. The tip of the small hour hand is shaped like a leaf. "T. GAUNT / MELBOURNE" is printed in black on the clock face. The winding key hole is just below the centre of the clock face. The key winds a fusee chain mechanism, attached to the brass mainspring barrel that powers the pendulum with an 8-day movement. The speed of the clock can be adjusted by changing the position of the weight on the pendulum, lengthening or shortening the swing; raising the pendulum shortens its swing and speeds up the clock. The metal fusee mechanism has an inscription on it. The rectangular wooden casing is with a convex curve at the bottom that has a hinged door with a swivel latch. The original stained surface has been painted over with a matte black. There are two other doors that also allow access to the clock’s workings. The case fits over the pendulum and workings at the rear and attaches to the clock by inserting four wooden pegs into holes in the sides of the case then into the back of the clock. A flat metal plate has been secured by five screws onto the top of the case and a hole has been cut into it for the purpose of hanging up the clock. There is a nail inside the case, possibly used for a place to the key."T. GAUNT MELBOURNE" is printed on the clock face. “6 1 3” embossed on the back of the fusee mechanism behind the clock. warrnambool, shipwrecked coast, flagstaff hill, flagstaff hill maritime museum, maritime museum, shipwreck coast, flagstaff hill maritime village, shipwrecked artefact, clock, warrnambool post office, fusee, henry walsh jnr, thomas gaunt, t gaunt & co, post office clock

A sextant is an astronomical instrument used to determine latitude and longitude at sea by measuring angular distances, especially the altitudes of the sun, moon, and stars. It is a doubly reflecting navigation instrument and used mainly by sailors to measure the angular distance between two visible objects. The name comes from the Latin sextans, or “sixth part of a unit,” because the sextant’s arc can be 60° or 120° of a circle depending on the model used. The primary use was to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle is known as sighting or shooting the object, or taking a sight. This angle and the time when it was measured is used in order to determine Greenwich Mean Time and hence longitude. Sighting the height of a landmark on land can also give a measure of distance from that object. History: The development of the sextant was as an improvement over the octant, an instrument designed to measure one's latitude. The octant was first implemented around 1731-present but can only measure angles up to 45°. As larger angles were needed to allow the measurement of lunar objects - moon, stars and the sun - at higher angles, the octant was superseded by the sextant. The sextant is a similar instrument but better made and allows larger angles from 60° to 120°. This improvement allows distances to be accurately calculated thereby giving longitude when used with a chronometer. The sextant was derived from the octant in 1757, eventually making all previous instruments used for navigational positioning obsolete. The sextant had been attributed to by John Hadley (1682–1744) and Thomas Godfrey (1704–1749), but reference to the sextant was also found later in the unpublished writings of Isaac Newton (1643–1727). Earlier links can be found to Bartholomew Gosnold (1571–1607) indicating that the use of a sextant for nautical navigation predates Hadley's implementation. In 1922, the sextant was modified for aeronautical navigation by Portuguese navigator and naval officer Gago Coutinho. It should be noted that the octant and quadrant are in the same family as they were, and all are, regarded as sextants. The sextant is representative of it's type and although not fully complete it demonstrates how 18th,19th and 20th century mariners determined their latitude and longitudinal to determine their position on a chart, allowing them to navigate there way across the world's oceans. It also demonstrates the skill and workmanship of the early instrument makers that operated scientific instrument businesses from London and other areas of England to provide most of the navigational instrumentation used by commercial and military navies of the time.Sextant with square, fitted box of polished wood, "Hezzanith" brand. Box contains many parts for the sextants use. On certificate "Heath & Co, London. Sextant Number Y 822". Catch on lid "DEFIANT LEVER" and "PATENT NUMBER 187.10". Maker's certificate is attached to the inside of the box.flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, sextant box, sextant, hezzanith, heath & co, navigational instrument, george wilson heath, astronomical instrument, instrument manufacturers, scientific instrument, navigation, celestial navigation, octant, quadrant, lunar navigation

An Octant is a doubly reflecting navigation instrument used primarily by sailors to measure the angular distance between two visible objects and was a forerunner of the sextant. The name comes from the Latin octo, or “one-eighth of a circle,” for the Octant’s arc which spans 45°, or one-eighth of a circle. The primary use of an Octant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle is known as sighting or shooting the object, or taking a sight. The angle, and the time when it was measured, can be used to calculate a position line on a nautical chart (latitude), for example, sighting the Sun at noon or Polaris at night (in the Northern Hemisphere) gives an angle by which the latitude can then be estimated. Sighting the height of a landmark on land can also give a measure of distance. History: The principle of the Octant as an instrument to measure ones latitude was first implemented around 1742-present but was superseded by the improvement of the octant to a sextant, a very similar instrument, better made and able to measure bigger angles 120°, allowing the measurement of Luna distances to give longitude when used with an accurate chronometer. The sextant started to appear around 1730 and had been attributed to by John Hadley (1682–1744) and Thomas Godfrey (1704–1749), but reference to the sextant was also found later in the unpublished writings of Isaac Newton (1643–1727). Earlier links can be found to Bartholomew Gosnold (1571–1607) indicating that the use of a Sextant for nautical navigation predates Hadley's implementation. In 1922, the sextant was modified for aeronautical navigation by Portuguese navigator and naval officer Gago Coutinho. Henry Hemsley was a lesser-known instrument maker and optician working in London in the late 17th and early 18th century. However, it should be noted that there were two Henry Hemsley opticians and instrument makers around this period. (Henry Hemsley 1, 1786-89, who had premises at 85 Fleet St London and Henry Hemsley 2, 1828-56), whose workshop was at 135-138 Radcliff Highway London. Therefore, based on the inscribed workshop address Henry Hemsley 2 is responsible for making this example.The octant is representative of its type and although not fully complete it demonstrates how 18th and 19th-century mariners determined their latitude on a chart to navigate their way across the world's oceans in the 18th and 19th century. It also demonstrates the skill and workmanship of the early instrument makers that operated from London at this time and provided most of the navigational instrumentation use by commercial and military navies of the time.Octant, ebony wooden frame and handle. Scale is missing from recess in frame. "H. Hemsley 135-138 Ratliff Highway, London", no box"H. Hemsley 135-138 Ratcliff Highway, London"flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, navigation, navigational instrument, instrument used for navigation, sextant, henry hemsley, instrument maker, london, octant