Posts Tagged ‘chronometer’

COOK – HARRISON – GREEN: THREE YORKSHIRE MEN WALKED INTO A BAR

Wednesday, August 23rd, 2017

 

‘He [John Harrison] wrested the world’s whereabouts from the stars, and locked the secret in a pocket watch’. Dava Sobel, Longitude, Fourth Estate, London, 1998

Harrison H-4 Chronometer

Since earliest times Europe’s sea-faring nations England, Portugal, France, Spain the Netherlands vied with each other to solve – the Holy Grail of Navigation – longitude – calculating with precision a ship’s position at sea while beyond sight of land.

Cornwell – 1707:  In heavy weather six (6) of Admiral Clowdisley Shovell’s ships lost their bearings off the Cornish coast and dashed to pieces against the Scilly Isles with the loss of 1500 lives

1714  – Westminster: An enquiry into England’s first recorded 18th century maritime disaster resulted in legislation- The Act of Longitude 1714.

A Board of Longitude was established under the Act. Its task to invite and evaluate submissions and award a prize of £20,000 to whom-so-ever solved the problem of determining longitude at sea.

To the detriment of the world’s seafarers the contest developed into a naked grab for cash. The king’s ransom, reckoned now more than £400,000,000 did much to delay recognition of the solution at the cost of countless lives.  See: Lotto and Longitude

There were only two (2) viable contenders for the Longitude Prize. Astronomer Royal Rev. Nevil Maskelyne’s Nautical Almanac , a system of  Luna Tables  and Star Cataglog favoured by a succession of Astronomer Royals and a sea-going ‘pocket-watch’ the invention of John Harrison a Yorkshire carpenter.

‘The Board of Longitude was top-heavy with astronomers, mathematicians and navigators…[Harrison] made a special enemy of the Reverend Nevil Maskelyne the fifth astronomer royal, who contested his claim to the [Longitude] prize money and whose tactics at certain junctions can only be described as foul-play’. Dava Sobel. ibid.

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THE THIRD MAN – CHARLES GREEN

Tuesday, August 15th, 2017

‘The grim roll-call broke his [Cook’s) heart…the death of the astronomer Charles Green marked a wave of those who ‘departed this life’….By the end of January [1771] they had barely enough men to man the ship [HMS Endeavour]’. Vanesssa Collingridge, Captain Cook, The Life, Death and Legacy of History’s Greatest Explorer, Ebury Press, 2002

Swinton- 1734: Charles Green son of ‘a prosperous’ free-hold Yorkshire farmer, born in Swinton towards the end of 1734, received a broad education with a strong emphasis on science.

London: John his elder brother took Holy Orders and established a school in Soho, London where Charles found his ‘heavenly passion’ astronomy. He stayed and taught mathematics after graduating.

Greenwich 1760: In 1760 Charles Green applied successfully for the position of Assistant Astronomer at Greenwich Observatory. He went on to serve as Chief Assistant to three (3) Astronomer Royals, James Bradley, Nathaniel Bliss and briefly to Reverend Nevil Maskelyn.

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In 1675 King Charles II engaged Sir Christopher Wren to design a National Observatory. Wren considered the ruins of Greenwich Castle a perfect site. Although Oliver Cromwell’s Roundhead Model Army had destroyed its buildings during The Protectorate Interregnum (1653-59) its foundations were left  intact.

Greenwich: In 1676, Rev. John Flamsteed, England’s inaugural Astronomer Royal, took up residence in the newly minted Greenwich Observatory. He remained in the role until his death in 1720.

Edmond Halley of comet fame succeeded Flamsteed holding  the post for twenty-two (22) years until his death in 1742.

Rev. James Bradley followed Halley. His tenure too was lengthy 1742-1762. Bradley is celebrated principally for his work on the speed of light. In 1728 he estimated light moved at the speed of 295,000 km (183,000 miles) per second.

Three (3) centuries later Bradley’s calculations were amended slightly to 299,790 km (186,290 miles) per second.

Arguably had Bradley stuck to light and left longitude to Mr. John Harrison inventor of the H-4 sea-going ‘pocket-watch’ many a sea-farer would not have met a watery end. Bradley died in 1762

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MOON VERSUS MACHINE

Tuesday, August 15th, 2017

Compared with that of Banks, Mr. Green’s equipment was comparatively modest. On May 5th, 1768, at a meeting of Council of the Royal Society it was resolved that the instruments for the use of the Observers of the South Latitudes be the following:

Two [2] reflecting telescopes of two [2] foot focus…[1] brass Hadley’s sextant, [1] barometer bespoke of Mr Ramsden, [1] Journeyman’s Clock bespoke by Mr Skelton, two [2] Thermometers of Mr Bird, [1] Stand for Bird’s Quadrant, [1] dipping needle bespoke by Mr Ramsden’. H.C. Cameron, Sir Joseph Banks, Angus and Robertson, Sydney, 1966

Who was Mr. Green? Charles Green was former Assistant to Rev. James Bradley and Rev. Nathaniel Bliss, both Astronomer Royals of Greenwich Observatory.

Tahiti: After the Admiralty rejected Alexander Dalrymple, member of the influential Scots ‘Dalrymple Dynasty’, first choice of the Royal Society, that august body engaged Green to represent them at Tahiti. He would assist Lieutenant James Cook RN in observing and recording the Transit of Venus due to take place at Tahiti on 3rd June 1769. See: The Third Man

‘John Harrison, the man who solved longitude in 1759’. Peter Ackroyd, Macmillan, London, 2016

Why ten (10) years after the longitude problem had been solved was Harrison’s marine chronometer ‘H-4 bolted to a window seat in the [Greenwich] Observatory’ and not aboard HMS Endeavour when Green set off for Tahiti with Lieutenant James Cook. See: Captain Cook, John Harrison, Charles Green – Three Yorkshire Men Walked Into A Bar

‘H-4 [was] bolted to a window seat in the Observatory’.  Dava Sobel, Longitude, Fourth Estate, London, 1998

No doubt H-4 sat under the watchful eye of Rev. Nevil Maskelyne. Britain’s fifth Astronomer Royal. Maskelyne had been elected to that high post in 1765 on the death of Rev. Nathaniel Bliss. Maskelyne held a conservative stranglehold over the position until 1811.

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LOTTO AND LONGITUDE

Wednesday, August 9th, 2017

‘But by reason of the motion of the Ship, the Variation of Heat and Cold, Wet and Dry, and the Difference of Gravity in different Latitudes, such a watch hath not yet been made”. And not likely to be, either, he implied’.  Isaac Newton cited, Dava Sobel, Longitude, Fourth Estate, London, 1998

‘Not likely’ however in 1736-7, just ten (10) years after Newton’s death (1727) on a supervised timed voyage, England to Lisbon aboard HMS Centurian, H-1 an early model of John Harrison’s  marine watch – had proved a reliable time-keeper.

‘He [Harrison] succeeded, against all odds, in using the fourth – temporal – dimension to link points on the three-dimensional globe’. Sobel. ibid.

Accurate time-keeping was essential for the calculation of longitude at sea. John Harrison a Yorkshire carpenter solved that problem. His  invention – a sea-going ‘pocket watch’ – gave a ship’s precise position when beyond sight of land.

‘John Harrison, the man who solved longitude in 1759’. Peter Ackroyd, Revolution, Macmillan, London, 2016

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