Inside the reef at this point the lagoon was too deep to distinguish the bottom, while, judging from the colour of the water, it descended abruptly into a large hole or crater. After sounding for two hours we found that such was the case, for, although the average depth of the lagoon was but six fathoms, there was a sunken bed, roughly 400 yards in length and 120 in breadth, where bottom was found at from twelve to fifteen fathoms, the deepest part being close to the reef. By the "arming" of the lead--the tallow placed in a cavity in the bottom of the sinker--the bed was found to be composed, not of fine white sand like the greater part of the lagoon, but of mud and sand mixed into a dark, gritty substance, with plenty of vegetable growth. It was the time of spring tides, and the rise, though but three feet, was sufficient to prevent the divers from descending on account of the constant swell over the reef; so, while waiting till the tide had subsided sufficiently to allow the coral to act as a breakwater, the grapnels were brought into play in the hope of finding some portions of the wreck. Cast after cast resulted in nothing more than the disturbing of the bottom to such an extent that the clear water became discoloured till it resembled liquid mud, and though masses of long, tendril-like seaweed were brought up, there were no indications of any foreign substance lying on the floor of the lagoon. At length one of the irons brought up a piece of wood, water-logged and covered with weeds and barnacles. Whipping out his knife, Uncle Herbert scraped the excrescences from the piece of timber and, to the delight of the crews of both boats--for the whaler, on hearing of the find, had come alongside the gig--he announced that it was a fragment of oak planking, with the marks of the bolts and trenails still plainly visible. "It's part of an old ship, beyond doubt," he remarked. "See! the wood is almost as hard as iron, yet black with years of submersion in salt water. I think we are somewhere near the mark." "So far, so good," replied my father. "But I think we'll have a spell now. Just buoy the spot before we leave, and the divers can descend later in the day." We returned to the "Fortuna," the boats being left at the booms instead of being hoisted inboard, while the diving-suits were carefully overhauled and the valves tested. While we were at lunch the bos'n reported: "Natives coming off, sir." "Bother the natives!" exclaimed Dr. Conolly. "Their attentions are becoming too frequent. Let's see what they want this time." Upon going on deck we found that a fleet of twenty small outrigger canoes was approaching, their occupants being without the war costumes which they wore on the previous occasion. As they came nearer they waved their hands in token of friendship, and displayed baskets of yams, coconuts, taro, and bananas, while one or two had live pigs trussed to bamboos.