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 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.

1714  – Westminster: Legislation, The Act of Longitude 1714, followed an enquiry into England’s first recorded 18th century maritime disaster.

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

As a consequence in 1714 The Board of Longitude was established 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; ‘the perfect time-keeper…a pocket- watch’. .

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

‘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.

The contest cost countless lives.

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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

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.

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.

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, Nathenial Bliss and briefly Reverend Nevil Maskelyne.

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

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

Had Bradley stuck to light and left longitude to Mr. John Harrison inventor of an accurate marine chronometer – a sea-going ‘pocket-watch’ – many a sea-farer would not have met a watery end.

 

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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 James Bradley and Nathaniel Bliss, Astronomer Royals of Greenwich Observatory. He was engaged by the Royal Society to represent them and assist Lieutenant James Cook RN observe and record the Transit of Venus due to take place at Tahiti on 3rd June 1769.

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

Why was Harrison’s marine chronometer ‘H-4 bolted to a window seat in the [Greenwich] Observatory’ when Green set off for Tahiti aboard HMS Endeavour 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 on a timed voyage, England to Lisbon aboard HMS Centurian, H-1 an early model of John Harrison’s  marine watch – 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  with his sea-going ‘pocket watch’ that 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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