Depictions of the island as an earthly paradise did not stem solely from sexual interaction. The climate was balmy, food was fresh and plentiful, and while the inhabitants were light-fingered, they were usually friendly.
While the Dolphin sailed with a high opinion of Tahiti and the Tahitians, tThe most important information they took with them when they sailed came from John Harrison, the purser, a man with ‘a very Mathematical Turn’, whose precise astronomical observations using ‘Dr Masculines Method which we did not understand' were remarkably accurate. Harrison fixed the island's position at 17°30'S and 150°W (today's precise location: 17°37'S 149°27'W) almost in the centre of the zone south of the Equator that Astronomer Royal Nevil Maskelyne figured as most favourable for observing the Transit of Venus.
Less definite were sightings of land to the south that helped shape the secret instructions given to Cook before he departed from England in 1768 and subsequently resulted in the commissioning of the second voyage, which saw Cook hound Terra Australis Incognita into oblivion.
In his journal, on 19 June 1767 George Robertson, master of the Dolphin recorded sighting
Land bearing W 1/2 S [that] appeared to be a great high mountain covered with clouds on the top; at 6 A.M. the Extreme of this Land bore from W 1/2 S to W.B.N. 1/2 N distance about 14 Leags at same time we saw the tops of several mountains the Extreems bearing from South to S.W. upwards of twenty Leags ... we now suposed we saw the long wishd for Southern Continent, which has been often talkd of, but neaver before seen by any Europeans.
However, while various members of the expedition kept eighteen different journals, Robertson’s is the only one that mentions such a sighting. What Robertson recorded was almost certainly a cloud bank on the horizon that he interpreted as cloud-covered mountaintops. Tahiti, according to Robertson was a peninsula of the southern continent. While the Tahitians indicated the insularity of their homeland, Robertson was dismayed when Wallis decided to head west when he left Tahiti rather than pursue mirages on the horizon.