Bligh published no narrative of this expedition; but Flinders was already accustoming himself to keep careful notes of his observations. Twenty years later, when preparing the historical introduction to his Voyage to Terra Australis, he wrote out from his journal (and with Bligh's sanction published) an account of the passage of the Providence and Assistant through Torres Strait, as a contribution to the history of navigation and discovery in that portion of Australasia. From the Pacific to the Indian Ocean the passage was accomplished in nineteen days. "Perhaps," commented Flinders, "no space of 3 1/2 degrees in length presents more dangers than Torres Strait, but with caution and perseverance the captains, Bligh and Portlock, proved them to be surmountable, and within a reasonable time." Bligh's Entrance and Portlock Reef, marked on modern charts, are reminders of a feat of navigation which even nowadays, with the dangers accurately described, and the well-equipped Torres Strait pilot service to aid them, mariners recognise as pregnant with serious risks. On this occasion it was also attended with incidents which make it worth while to utilise Flinders' notes, since they are of some biographical importance. The high lands of the south-eastern extremity of Papua (New Guinea), were passed on August 30th, and at dusk on the following day breakers "thundering on the reef" were sighted ahead. On September 1st the vessels edged round the north end of Portlock Reef. Thence the monotonous record of soundings, shoals, reefs seen and charted, passages tried and abandoned, in the prolonged attempt to negotiate a clear course through the baffling coral barrier, is relieved by the story of one or two sharp brushes with armed Papuans in their long, deftly-handled canoes. On September 5th, while boats were out investigating a supposed passage near Darnley Island, several large canoes shot into view. One of these, in which were fifteen "Indians," black and quite naked, approached the English cutter, and made signs which were interpreted to be amicable. The officer in charge, however, suspecting treacherous intentions, did not think it prudent to go near enough to accept a green cocoanut held up to him, and kept his men rowing for the ship. Thereupon a native sitting on the shed erected in the centre of the canoe, called a direction to the Papuans below him, who commenced to string their bows. The officer ordered his men to fire in self-defence, and six muskets were discharged.