For twenty-four hours he sailed quietly on, the wind dropping lighter and lighter; then it suddenly died out altogether; for some hours there was not a breath to stir the surface of the water, and the heat was stifling. Gervaise slept for some time; when he awoke the same stillness reigned, but there was a change in the appearance of the sky; its brightness was dulled by a faint mist, while, although the sea was of a glassy smoothness, there was an imperceptible swell that caused the felucca to sway uneasily. Gervaise had sufficient experience of the Levant to know that these signs were ominous of a change, and he at once set to work to prepare for it. Although he saw that it would be difficult for him unaided to hoist the long spar back into its place, he decided to lower it. This was not difficult, as its weight brought it down on to the deck as soon as he slackened the halliards; he unhooked it from the block, and then lashed the sail securely to it. When he had done this he looked round. A bank of dark clouds lay across the horizon to the northwest, and in a short time he could see that this was rising rapidly.