1663 – England: In 1663 during the reign of King Charles II (1660-1685) a collection of ‘enquiring men of science’ – the ‘Invisible College’ – morphed into the Royal Society.

A century later, between 1760 and 1820 under the patronage of King George III, the Society flowered into one of the world’s most celebrated scientific institutions.

In 1767 with the Transit of Venus in the offing – 3 June 1769 – its second appearance that decade – the Society petitioned King George III for financial support to send observers to report on the phenomenon.

1768 – February: To that end James Douglas 14th Earl of Morton, then President of the Royal Society, on 15 February 1768, penned a Memorial requesting the Monarch’s financial support.

‘That the passage of the Planet Venus over the Disc of the Sun, which will happen on the 3rd of June in the year 1769, is a Phaenomenon (sic) that must, if the same be accurately observed in proper places, contribute greatly to the improvement of Astronomy on which Navigation so much depends.

 As the [Fellows] are in no condition to defray this Expense about £4,000 pounds, exclusive of the Expense of the Ships…with all humility and submit the same to your Majesty’s Royal consideration’. Cited, H.C. Cameron, Sir Joseph Banks, Angus and Robertson, Sydney, 1968

Royal money was forthcoming for it was clear accurate and reliable navigation could equate with domination over the seas. Domination would expedite expansion of territory and trade and likely assure victory in war.

‘And the sum of £4,000 pounds clear of fees, [was] to be placed at the disposal of the Society…On March 5th of the next year, 1768, the Navy Board was instructed by the Admiralty to purchase a suitable vessel for the great voyage to the South Seas’. Cameron, Sir Joseph Banks, Angus and Robertson, 1968

‘The Transit was more than just an astronomical curio, it was the key to a wealth of information about the universe, information that would be seized upon by the intensely curious men of science who characterised the age’. Vanessa Collingridge, Captain Cook, The Life, Death and Legacy of History’s Greatest Explorer, Random House, 2003

1768 – 5 March: Admiralty settled on the Earl of Pembroke. A typical coal carrier ‘cat-built bark’ of 368 tons, described as ‘stoutly built, flatly bottomed of shallow draught’ she was renamed HMS Endeavour.

 ‘In the all important question of the command of the expedition there was at first a difficulty….The Royal Society had accepted the recommendation of the Astronomer Royal [Nevil Maskelyne] that the well-known hydrographer Mr Dalrymple…should be chosen as ‘a proper person to be sent to the South Seas’ in the capacity of Chief Observer’. Cameron. ibid.

But the Admiralty in a stunning reversal of protocol selected James Cook a mere Warrant Officer then aged thirty-eight (38), not only to captain HMS Endeavour he was given overall ‘management’, command of the expedition and that included the role of Chief Observer.

It would be an understatement to say Cook’s appointment disturbed many illustrious members of the Society who were convinced that, at the very least, the role of Chief Observer should have been given to Alexander Dalrymple a highly favoured Fellow of the Society.

He [Dalrymple] would not make the voyage at all…on any footing than that of having management of the ship…I can give no thoughts of undertaking the voyage as a passenger going out to make the observation’. Cameron. ibid.

 Dalrymple son of a wealthy well-connected Scottish family, obsessed by the romance of the South Seas and intrigued by the fabled Terra Australis Incognita, was devastated by the Admiralty’s rebuff.

Cameron says Dalrymple failed to appreciate his demand; ‘having management of the ship [was] entirely repugnant to the regulations of the Navy’. 

 ‘The Admiralty based its refusal on the unfortunate results which had followed when the astronomer Edmund Halley had been placed in command of the war-sloop Paramour Pink.

 Halley had sailed in 1698 on a voyage to study the variations of the compass but was forced to return because of the mutinous conduct of the crew’. Cameron ibid.

 Now in 1768 the Navy, having supplied HMS Endeavour and paid her crew, was not about to give over another king’s ship to a hot-headed civilian whose arrogance was sure to get up the noses of professional seamen.

But the Admiralty’s rejection also reflected on Astronomer Royal Nevil Maskelyne who had championed Dalrymple’s cause that could have had the most serious of consequences.

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

But when HMS Endeavour sailed to Tahiti and onto the South Seas in search of the fabled Great South Land she went without John Harrison’s accurate marine chronometer the H-4.

Dava Sobel tells; ‘H-4 [was] bolted to a window seat in the Observatory’ no doubt under the watchful eye of Reverend Nevil Maskelyne.

If Cook had known the precise position of his ship while in vast uncharted waters Endeavour may not have had to spend as much time at sea as it did and not so many Endeavour lives lost.

At Batavia, homeward bound Cook lost one half of Endeavour’s debilitated crew to malaria and dysentery among them astronomer Charles Green.  Of Joseph Bank’s party of ten (10) only four (4) – including Banks himself – survived. See: Cook, Harrison, Green – Three Yorkshire Men Walked Into A Bar – Nevil Maskelyne 


Admiral Shovell’s disastrous multiship wreck off the Scilly Isles after the turn of the eighteenth century [1707 had] intensified the pressure to solve the longitude problem’. Dava Sobel, Longitude, Fourth Estate, London, 1998

In Longitude Dava Sobel has dissected forensically the Astronomers Royal of that time at Greenwich Observatory and in particular Maskelyne and his relentless persecution of John Harrison inventor of the sea-going ‘pocket watch’.

Following the Scilly disaster off the Cornwell coast (1707) Parliament passed the Longitude Act of 1714. A Board of Longitude was established charged with solving the ‘longitude problem’.

From its inception the Board was dominated by Britain’s Astronomer Royals – John Flamsteed 1675-1719, Edmond Halley 1720-1742, William Bradley 1742-1762, Nathaniel Bliss 1762-1764 and Nevil Maskelyne 1765 -1811.

Dava Sobel has paid particular attention to Reverend Nevil Maskelyne arguably the most problematic of these gentlemen. Maskelyne, smarting from the Admiralty’s rejection of Dalrymple, was responsible for with-holding H-4 from Lieutenant James Cook on the Endeavour voyage. See: Captain Cook Caught Short

In 1768 however not all Royal Society’s Fellows would not have been upset by the selection of James Cook to lead the Transit expedition among them Earl Morton the Society’s President.

Between 1762 and 1764 James Cook had spent his summers surveying and charting the coastline of Newfoundland. When published his maps received critical acclaim.

In 1766 Cook submitted the Royal Society a meticulous report on his observation of the eclipse of the sun made that year in Newfoundland. It was Cook’s charts that convinced Earl Morton this lowly warrant officer was eminently suitable for the task as Chief Observer of the Transit of Venus.

James Cook RN born in Yorkshire in 1728 was commissioned First Lieutenant on 25 May 1768.

‘Thereafter the Admiralty and the Royal Society worked amicably together in a vast amount of necessary preparation’. Cited, Cameron. ibid.

And then of course there was the Great Southern Land. Cook after observing the Transit was to open ‘Secret [Admiralty] Instructions’ ordering he sail further south in search of the fabled Great South Land and, if such a land-mass did exist, assess if it was worthy of and ripe for invasion?

‘You [Cook] are also to be careful to observe the nature of the soil and the products thereof, the beasts and fowls that inhabit or frequent it; the fishes that are to be found in the rivers or upon the coast, and in what plenty, and in case you find any mines, mineral or valuable stones, you are to bring home specimens of each.

 You are likewise to observe the genius, temper, disposition and number of the Natives.’ Public Records Office Admiralty 2/1132, issued July 30, 1768, cited Cameron.

Following the Admiralty’s refusal to accept Dalrymple the Royal Society looked to Greenwich Observatory and engaged Charles Green to act as Cook’s assistant.

Green born in Yorkshire in 1734 was an excellent choice. Although still a young man, he had served as assistant to three (3) Astronomer Royals – Bradley, Bliss and very briefly – two (2) months – under Nevil Maskelyne.

The three (3) highly educated astronomers and gifted mathematicians were, unlike Green, wedded to old technology. Celestial navigation based solely on the movement of heavenly bodies – moon and stars – these had been set down in Luna Tables and Star Catalogue by John Flamsteed Britain’s first Astronomer Royal 1675-1719.

A century earlier Nicholas Copernicus born in Poland in 1514, when a young man, moved to Bologna to study cannon law and became interested in astronomy.

Shortly before dying in 1543 his opus ‘De Revolutionilus Orbioum Caelestium’ was published. In it Copernicus described a model of the solar system that placed the sun not earth at its centre.

Then came Italy’s Galeileo Galilei ‘father of observational astronomy’ 1564 -1642 and Johannes Keppler his German contemporary 1571-1630 with an improved telescope.

Englishman Jeremiah Horrocks 1618-1641 was the first person to demonstrate the moon’s elliptical orbit. In 1639 amidst the horror and chaos of England’s Civil Wars Horrocks observed the Transit of Venus and recorded the phenomena in his Treatise ‘Venus in sole visa’.

‘On the day before reliable time-keeping, the skies were used as a giant clock’. Vanessa Collingridge. Ibid

No doubt Luna Tables were well suited to static land-based platforms such observatories in France, Germany, Italy, Russia and Britain. However, in pitching seas under dense cloud on dark and stormy nights, the required complicated calculations were ‘difficult to execute’.

During Edmond Halley’s tenure at Greenwich 1720-1742 a revolution in time-keeping had taken place. John Harrison’s marine chronometer H-I, had shown as early as 1736-7, on a timed voyage from England to Lisbon aboard HMS Centurian, the sea-going ‘watch’ was capable of ‘reliable time-keeping’.

However in the mid 1760s the Astronomer Royals of Greenwich Observatory had not moved on and argued vehemently for the efficiency of Lunar Tables.

‘The Board of Longitude was top-heavy with astronomers, mathematicians and navigators’. Daval Sobel, Longitude, Fourth Estate, London, 1998

Edmond Halley died in 1742 and James Bradley who succeeded him held the post of Astronomer Royal for twenty (20) years during this time he remained wedded to Luna Tables. Green, a young mathematician and astronomer, dared to be different he celebrated the coming of the ‘Watch’.

On Bradley’s death in 1764 Nathaniel Bliss succeeded as Astronomer Royal. His two (2) year tenure was dogged by ill-health so much so he did not take residence at Greenwich and during this time Green functioned as surrogate Astronomer Royal. 

 1761- November:  Green believed time was the essential ingredient in establishing longitude at sea. However when John Harrison, William’s son boarded HMS Deptford with H-4 for yet another time-trial, Portsmouth to Jamaica, the argument over the reliability of Harrison’s ‘watch’ was still raging.

Not long into the Jamaica voyage it was discovered much of Deptford’s food was rotten and even more disastrous the grog had gone off; ‘with all the Beer gonethe People were obliged to drink water’.

Dudley Digges, Deptford’s captain, made for Madeira with all haste he took a bet with William Lyttleton who was on his way to Jamaica to take up position of Governor.

Dava Sobel’s Longitude tells it best.

‘William [Harrison] promised a speedy end to the distress, as he reckoned with H-4 that the Deptford would make Madeira within a day. Digges argued that the Watch was way off, as was the island, and offered to lay odds on the bet.

 Regardless the next morning brought Madeira into sight – and fresh barrels of wine into the hold. At this junction Digges made Harrison a new offer: he would buy the first longitude timekeeper that William and his father put up for sale, the moment it was available.

 While still in Madeira, Digges wrote to John Harrison: “Dear Sir, I have just time to acquaint you…of the great perfection of your watch in making the island on the Meridian.

According to our Log we were 1 degree 27 minutes to the Eastward, this I made by a French map which lays down the longitude of Teneriffe, therefore I think your watch must be right’. Cited in Sobel. ibid.

 But nothing would be good enough for the Board of Longitude dominated at this point by Nathaniel Bliss who; ‘like Bradley before him was all for lunars’.

 ‘He [Bliss] insisted that the Watch’s so-called accuracy was a mere chance occurrence, and he did not predict a precision performance on the next trial’. Sobel. ibid.

1764 – March: The next trial came two (2) years later. In March of 1764 William Harrison with a friend Thomas Wyatt boarded H.M.S. Tarter and sailed with H-4 to Barbados.

Bliss, now close to death, sent Charles Green and Nevil Maskelyne to Barbados to evaluate H-4’s performance.

‘The Tartar’s captain, Sir John Lindsay, oversaw this first phase of this trial, and monitored the handling of the Watch on the way to the West Indies.

 After HMS Tarter arrived on May 15, Lindsay compared notes with the board-appointed astronomers who had preceded him to the island aboard the Princess Louisa, William [Harrison] found a familiar face.

There at the observatory, standing ready to judge the performance of the Watch, was Nathaniel Bliss’s hand picked henchman, none other than the Reverend Nevil Maskelyne.

En-route to Barbados, [Maskelyne] boasted he was sure he’d clinched the case and secured the prize.

When William heard word of these claims, he and Captain Lindsay challenged Maskelyne’s fitness to judge H-4 impartially.

Maskelyne was outraged by their accusations.

 He became huffy,  then nervous. In his disquieted condition, he botched the astronomical observations – even though all those present recalled there wasn’t a cloud in the sky.’ Sobel. Ibid

 Charles Green at Barbados in 1764, like Captain Digges in Jamaica 1761, had no doubt of H-4’s efficacy.

It would not then be hard to imagine Charles Green’s frustration when he joined HMS Endeavour for the voyage to Tahiti and the South Seas to find the Admiralty had not demanded a H-4 chronometer be supplied to Lieutenant James Cook RN.

Nor can it be doubted during Endeavour’s long three (3) year voyage Charles Green convinced Cook that sea-going clocks solved the knotty question of how to calculate longitude accurately when beyond sight of land.

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

 So why did HMS Endeavour sail without H-4 John Harrison’s now proven sea-going ‘Watch’ ?

 1765: Nathaniel Bliss died in 1764. After a  hiatus of six (6) months King George III appointed Rev. Nevil Maskelyne Astronomer Royal in February 1765. See: Lotto and Longitude

 1765 – 15 March: Green recorded his final observations at Greenwich Observatory on 15 March 1765 shortly before Nevil Maskelyne took up his appointment later in March. Maskelyne would hold the position for nigh on fifty (50) years 1765-1811.

It is possible to speculate irreconcilable differences, that had their origin on the Barbados trial of H-4  in 1764, were prominent among the reasons Charles Green quit Greenwich Observatory. See: Charles Green The Third Man

For more details on Dava Sobel’s book, Longitude, see:

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