With only a few days to go before the transit of Venus – the reason James Cook and his men voyaged to Tahiti in 1769 aboard the Endeavour – the captain was determined to do everything to ensure the operation stood the best chance of success.
The results of the previous 1761 expeditions had been disappointing and Cook, the ship’s astronomer Charles Green, as well as the members of the Royal Society back in England knew that another opportunity like this wouldn’t come along for over a hundred years.
The captain therefore followed the instructions he’d been given to the letter.
The ones he’d received from the Lords of the Admiralty came in two parts – the first concerning the observation of the transit.
Separately, the Royal Society had provided Cook and its own scientific representatives on the ship with some additional ‘hints’. These were written by the society’s president James Douglas, the 14th Earl of Morton and are available via the National Library of Australia.
The first set of suggestions advocated the humane treatment of indigenous people while the second focused on the astronomical aspect of the mission:
“The primary object of the expedition is to take a correct observation of the transit of Venus on the 3rd of June. No time therefore should be lost in getting to the station fixed upon for that purpose, there being many preparatory operations absolutely required, which my take up six seeks, or two months previous to the day of the transit.
“Least the state of the sky should happen to prove unfavourable for some days preceding the 3rd of June, it might perhaps be advisable to pitch upon two places at some miles distance from each other, verifying beforehand by repeated observations their different longitudes and latitudes.
“When these are well ascertained, should the morning of the transit or even the day before appear unfavourable an observer might be stationed at each of those places, because one of those observers might possibly see the phenomenon while the other could not.”
And so on May 31, the Endeavour’s Royal Society-appointed naturalist Joseph Banks, noted in his diary:
“In consequence of hints from Lord Morton the Captn resolves to send a party to the eastward, and another to Imáo, an Island in sight of us, thinking that in case of thick weather one or the other might be more successfull than the observatory.”
He was among the party dispatched the next day to this place, which was christened York Island in honour of King George III’s younger brother two years earlier by Samuel Wallis, commander of the first British expedition to Tahiti. Its Tahitian name is Mo‘orea. Cook wrote in his journal on June 1:
“This day I sent Lieutenant Gore in the Long-boat to York Island with Dr Monkhouse and Mr Sporing (a Gentleman belonging to Mr Banks) to observe the Transit of Venus, Mr Green having furnished them with Instruments for that purpose. Mr Banks and some of the Natives of this Island went along with them.”
The day after, Cook instructed the second observation group to head east.
“Very early this morning Lieutenant Hicks, Mr Clark, Mr Pickersgill and Mr Saunders went away in the Pinnace to the Eastward, with orders to fix upon some Convenient situation upon this Island, and there to Observe the Transit of Venus – they being likewise provided with Instruments for that purpose.”
Lord Morton’s hints took account of the fact that the voyage had limited equipment with which to carry out three independent observations and stressed that the principal focus should remain the camp Cook had established at ‘Point Venus’.
“As there is but one clock, that certainly should be fixed in the portable observatory; but that deficiency in the other place might in part be remedied, by adjusting a good second watch, marking its rate of going and its variations from the clock for eight or ten days before the day of the Transit.”
Morton then moved on to the second part of Cook’s mission:
“When that business is finished, other matters may be attended to, particularly, the discovery of a continent in the lower temperate latitudes.”
Morton’s hints highlighted the Royal Society’s desire for anthropological studies and the collection of plant and animal specimens from the fabled Terra Australis Incognita.
Cook’s instructions from the Admiralty made its own interests plain. While the transit of Venus could provide data capable of advancing navigation, a second, secret set of instructions made clear that these observations were merely a prelude to the main business.
“When this Service is perform’d you are to put to Sea without Loss of Time, and carry into execution the Additional Instructions contained in the inclosed Sealed Packet,” read the papers handed to the Endeavour’s captain.
These “additional instructions” detailed the requirement for Cook and his men to locate and chart the mysterious Great Southern Continent, conduct a thorough survey of natural resources including minerals and valuable stones and “take possession of Convenient Situations in the Country in the name of the King of Great Britain.”
These secret edicts, which can be found in The Explorations of Captain James Cook in the Pacific, ended with the strict requirement to keep his own journals confidential and return them to the Admiralty, along with any other records of the voyage kept by the Endeavour’s men.
“You are to send by all proper Conveyances to the Secretary of the Royal Society Copys of the Observations you shall have made of the Transit of Venus; and you are at the same time to send to our Secretary, for our information, accounts of your Proceedings, and Copys of the Surveys and drawings you shall have made.
“And upon your Arrival in England you are immediately to repair to this Office in order to lay before us a full account of your Proceedings in the whole Course of your Voyage, taking care before you leave the Vessel to demand from the Officers and Petty Officers the Log Books and Journals they may have Kept, and to seal them up for our inspection, and enjoyning them, and the whole Crew, not to divulge where they have been until they shall have Permission so to do.”