encompassed by a lofty and immensely solid wall, or quay, built of enormous blocks of granite the face of which had been worked to so smooth a surface as to render it absolutely unclimbable, the only means of obtaining a landing seeming to be by way of a double flight of wide stone steps leading up from the water to a wide platform which was shut off from the interior of the island by an immensely strong gateway flanked by two lofty towers. By the time that Dick and Grosvenor had become imbued with a fairly accurate general impression of the extraordinary characteristics of the mysterious unknown island city to which they were bound, the craft that bore them was close in under the frowning protective wall which engirdled it, and a few minutes later the boat ranged up alongside one of the two flights of landing steps, the paddles were laid in, and the crew, springing to their feet, checked the vessel's way by grappling a number of large bronze mooring rings the shanks of which were deeply sunk into the face of the massive masonry. Then the officer who had arrested the prisoners, and still had them in charge, gave the word to land, and the young Englishmen stepped ashore, closely followed by half a dozen men bearing their several belongings, except their firearms, which they insisted on carrying themselves. Ascending the long, easy flight of steps, the little procession, led by the officer, presently reached the broad platform on the top, and found themselves confronting a pair of enormous bronze doors which completely filled the gateway, and which swung slowly open, apparently by some mechanical means, to admit them. Passing through the gateway, and noting, as they went, the extraordinary strength and solidity of the doors, they found themselves in a kind of tunnel, or passage, some twenty feet long, in the structure of the gateway, with a sunlit vista of a paved street, bordered on either hand by lofty shade trees, with houses behind them, and thronged with people. Another minute and they had emerged from the archway and were in the street itself, which they now perceived to be one of the business streets of the island, for the houses on either side of it were arranged as shops, the whole of the lower part of each being open, affording a view of the various wares for sale, displayed upon a gently sloping platform, at the rear end of which sat the owner, cross-legged, Eastern fashion, arrayed in long flowing robes of brilliant hues. The fronts of the shops were unglazed, and unprotected by screen or barrier of any kind, nor did the shopkeeper make the slightest attempt to solicit custom; his property was simply protected from the ardent rays of the sun by a gaily coloured blind, or awning, and he sat silently and gravely awaiting the arrival of such customers as might chance to require the particular kind of wares that he had for disposal. These wares, it soon appeared, consisted chiefly