Posts Tagged ‘longitude’


Tuesday, August 15th, 2017

The Royal Society had accepted the recommendation of the Astronomer [Maskelyne] that [Dalrymple] the well-known hydrographer of the Pacific should be chosen as ‘a proper Person to be sent to the South Seas’. H.C. Cameron, Sir Joseph Banks, Angus and Robertson, Sydney, 1968

The Admiralty would have none of Alexander Dalrymple a Fellow of the Royal Society who Astronomer Royal Nevil Maskelyne adjudged ‘a proper Person to be sent to the South Seas’.

Instead Admiralty chose James Cook a lowly Warrant Officer of the Royal Navy to replace Maskelyne’s choice of Dalrymple as Chief Observer of the Transit of Venus at Tahiti predicted to occur in early June of 1769. See: Malicious Maskelyne 

‘[Cook] Whose remarkable qualities as a seaman and as a navigator and cartographer the Admiralty had learned to value because of his outstanding service in the operation under [General] Wolfe in Canada [Seven Years War 1756-1763]. Cameron. ibid. 



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

Here two (2) of a plethora of questions must be asked. Who was Mr. Green and why did HMS Endeavour sail on such an important voyage without Mr. John Harrison’s H-4 chronometer?



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’ – not so – as early as 1736, on a timed voyage, England to Lisbon aboard HMS Centurian, H-1 a marine clock had shown itself 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 to the calculation of longitude that gave a ship’s precise position at sea when beyond sight of land.

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

Harrison was the carpenter from Yorkshire whose invention, the sea-going watch, solved the problem of longitude.