Dillon guessed that the ships at issue were those under the Count de La Pérouse, ships whose disappearance had shaken the entire world. He tried to reach Vanikoro, where, according to the native boatman, a good deal of rubble from the shipwreck could still be found, but winds and currents prevented his doing so.
Dillon returned to Calcutta. There he was able to interest the Asiatic Society and the East India Company in his discovery. A ship named after the Search was placed at his disposal, and he departed on January 23, 1827, accompanied by a French deputy.
This new Search, after putting in at several stops over the Pacific, dropped anchor before Vanikoro on July 7, 1827, in the same harbor of Vana where the Nautilus was currently floating.
There Dillon collected many relics of the shipwreck: iron utensils, anchors, eyelets from pulleys, swivel guns, an eighteen-pound shell, the remains of some astronomical instruments, a piece of sternrail, and a bronze bell bearing the inscription "Made by Bazin," the foundry mark at Brest Arsenal around 1785. There could no longer be any doubt.
Finishing his investigations, Dillon stayed at the site of the casualty until the month of October. Then he left Vanikoro, headed toward New Zealand, dropped anchor at Calcutta on April 7, 1828, and returned to France, where he received a very cordial welcome from King Charles X.
But just then the renowned French explorer Captain Dumont d'Urville, unaware of Dillon's activities, had already set sail to search elsewhere for the site of the shipwreck. In essence, a whaling vessel had reported that some medals and a Cross of St. Louis had been found in the hands of savages in the Louisiade Islands and New Caledonia.
So Captain Dumont d'Urville had put to sea in command of a vessel named after the Astrolabe, and just two months after Dillon had left Vanikoro, Dumont d'Urville dropped anchor before Hobart. There he heard about Dillon's findings, and he further learned that a certain James Hobbs, chief officer on the Union out of Calcutta, had put to shore on an island located in latitude 8 degrees 18' south and longitude 156 degrees 30' east, and had noted the natives of those waterways making use of iron bars and red fabrics.
Pretty perplexed, Dumont d'Urville didn't know if he should give credence to these reports, which had been carried in some of the less reliable newspapers; nevertheless, he decided to start on Dillon's trail.
On February 10, 1828, the new Astrolabe hove before Tikopia Island, took on a guide and interpreter in the person of a deserter who had settled there, plied a course toward Vanikoro, raised it on February 12, sailed along its reefs until the 14th, and only on the 20th dropped anchor inside its barrier in the harbor of Vana.
On the 23rd, several officers circled the island and brought back some rubble of little importance. The natives, adopting a system of denial and evasion, refused to guide them to the site of the casualty. This rather shady conduct aroused the suspicion that the natives had mistreated the castaways; and in truth, the natives seemed afraid that Dumont d'Urville had come to avenge the Count de La Pérouse and his unfortunate companions.
But on the 26th, appeased with gifts and seeing that they didn't need to fear any reprisals, the natives led the chief officer, Mr. Jacquinot, to the site of the shipwreck.
At this location, in three or four fathoms of water between the Paeu and Vana reefs, there lay some anchors, cannons, and ingots of iron and lead, all caked with limestone concretions. A launch and whaleboat from the new Astrolabe were steered to this locality, and after going to exhausting lengths, their crews managed to dredge up an anchor weighing 1,800 pounds, a cast-iron eight-pounder cannon, a lead ingot, and two copper swivel guns.
Questioning the natives, Captain Dumont d'Urville also learned that after La Pérouse's two ships had miscarried on the island's reefs, the count had built a smaller craft, only to go off and miscarry a second time.