In searching for sunken vessels two boats are used, of the same general type as the "hydrographic submarine." When a wreck is located divers go out and examine it. If it is concluded that she has cargo on board worth salving, her location is plotted on the chart and then the recovery boats are sent out to remove the cargo. I have done much experimental work in locating sunken wrecks and recovering their cargoes. In 1898, 1899, and 1900 the _Argonaut_ and special wreck-finding apparatus were used in this experimental work. Numerous wrecks were found and a number of cargoes were profitably recovered, notwithstanding the fact that the apparatus used was crude and experimental. In 1901 I was called from this line of work to take up the construction of submarine torpedo boats, and have been too busy ever since, building for the United States and foreign governments, to find the time and opportunity to push on this very interesting phase of submarine work. [Illustration: THE "ARGONAUT" SUBMERGED Drawn by C. McKnight Smith for _Harper's Weekly_, April 1, 1899. (By permission. Copyright 1899 by Harper & Brothers.) This shows the remodelled "Argonaut" with her buoyant ship-shaped superstructure, on a submerged wrecking expedition, as was actually accomplished in the years 1900-1901.] Searching for sunken vessels is, perhaps, the most interesting of all submarine work. It is like fishing. One is always on the _qui vive_ for a "bite." There is hardly a location along our coast or in Long Island Sound that does not have a tradition about lost treasure ships, and every time one gets a "bite"--that is, our lines get fast to some sunken object--excitement runs high in the expectation of some valuable find. In my experimental work in the vicinity of Bridgeport, Connecticut, we located sixteen sunken vessels, the great majority of them containing coal, which we recovered at a cost of about fifty cents per ton. Most of these vessels had been sunk a long time. Only a few of them were known by name, and some had evidently been sunk many years. One that we searched for during several months had a cargo of copper ore and copper matté which was quite valuable. We finally found her several miles away from where people testified they saw her disappear.