Since 1904, a steamer has been employed each season by the government for dredging oysters in connection with experiments in oyster-culture. The officer in charge of this work concludes that “dredging is economically a more sound method of fishing than is diving.”[141] This view is disputed by the superintendent of the fishery, who points out that the average catch by the steamer when dredging mature oysters only slightly exceeds that of an ordinary diving boat, and the cost of maintenance and operation is vastly greater.[142] A remarkable tribute to the skill of the nude divers, brought out by this discussion, is that, during some days when they were at work, the sea was too rough for dredging by the steamer, notwithstanding that she was a typical Grimsby or North Sea trawler of 150 tons measurement, built in 1896.[143] A rough comparison of the Ceylon method of catching pearl-oysters with that practised by the American oyster-growers may not be uninteresting. On a basis of 400 to the bushel, the total Ceylon catch of 81,580,716 pearl-oysters in 1905 represents a trifle more than 200,000 bushels, or about the quantity annually produced by each of the half dozen leading oyster-growers of this country. Each one of these growers requires only about three steamers, at a total cost, maybe, of $25,000, and manned by twenty-five men; instead of one steamer at a cost of $25,000 and 318 diving boats manned by 10,000 men, which was the equipment in Ceylon. To be sure, the conditions under which the work is prosecuted are different—however, not so entirely unlike as might be supposed—and the American season is about six months long instead of the two months in Ceylon; but the comparison is presented simply as a suggestion of the possibilities of dredging on the Ceylon reefs. Until 1885, one of the most novel features of the fishery was the employment of shark-charmers or “binders of sharks” (_kadal-kotti_ in the Tamil language, _hai-banda_ in Hindustani), whose presence was rendered necessary by the superstition of the Indian divers. The fishermen placed implicit reliance upon the alleged supernatural powers of these impostors, resembling in some respects that reposed in the “medicine men” by the American Indians, and would not dive without their supervision. It is unknown at what period the influence of these semi-priests developed, but at the time of Marco Polo’s visit about 1294, they were in the full bloom of their authority, receiving one twentieth of the total catch of oysters,[144] which amounted to a very considerable sum. It is probable that the number of shark-charmers was then quite large, some writers more recently referring to one for each boat. During the Portuguese occupation the number was reduced to twelve, and at the beginning of the British influence, it was further reduced to two. Interesting descriptions have been given of the methods by which these men exercised their alleged powers. In 1807, Cordiner stated: