On reaching the fishing-ground the _sambûk_ anchors, under the shelter of a reef, perhaps miles out to sea, or perhaps near some islet or sandbank. The canoes with which it is loaded are launched and two men paddle away in each. Though both can dive they go in pairs distinguished as “captain” and “paddler,” the former being chosen for good eyesight and skill in distinguishing the pearl shells from the weeds, sponge, and stones among which they grow. A bad captain “sees every stone as a shell” which results in waste of energy in useless diving. He examines the sea-bottom by means of a “water telescope” (Arabic “Maraya,” a word also applied to mirrors, among other things), a paraffin tin with a glass bottom. The glass is pressed on the surface of the sea, thus flattening out ripples and giving a smooth surface through which, in this transparent sea, objects can be clearly seen at a depth of from twenty, thirty, and sometimes even sixty feet[35]. So the canoe is slowly paddled over the sea until a shell is sighted, when the canoe is manœuvred into the proper position, and the diver descends and secures it. The business is not generally a simple dive and return, though that is a clever enough thing to do without upsetting the canoe. In the case of not quite fully-grown oysters the creature is attached to the bottom by a very strong silky green cable, and I have watched the diver plant both feet firmly on the bottom, and wrench and twist at the sharp-edged shell with both hands for some time before it would come away. The average duration of a long dive is 90 seconds, two minutes being the longest I have seen. To one in the boat counting the seconds waiting for the reappearance of the diver this seems a long time, and doubtless the exaggerated reports of divers staying under water for five minutes have thus arisen. Two minutes of considerable exertion under the pressure of 30 ft. of water is surely a sufficiently remarkable feat. The greatest depth to which a naked diver descends is thirteen fathoms, equal to seventy-eight feet. _Plate XX_ [Illustration: Fig. 43. A pearl oyster seen; manœuvring the canoe] [Illustration: Fig. 44. The dive] [Illustration: Fig. 45. The “oyster” secured] [Illustration: Fig. 46. Landing on Dongonab beach] The captain only dives for an hour or two in the morning, after which he saves his eyes for finding the shells which his paddler secures. These men, whether Arabs of the _sambûks_ or Hamites who go out from their villages in canoes, dive without any apparatus at all. A few negroes descend by a weight and cord in likely places where the water is too deep to see the bottom, on the chance of coming across shells. The Hamites ridicule them for using this method, but so far as I can see their results are just as profitable. Two or three large shells seem to be considered an adequate reward for a day’s great labour.