The air was full of impalpable dust. To avoid suffocation or blindness therefrom, Skene dismounted, tied his gauze pugaree tightly over his face, and placing his camel between him and the skirt of the blast, which now developed into a wind-storm, sweeping the column of sand with wondrous speed before it, stooped his head close to the saddle and held on to a stirrup-leather. On came the wind-storm, and before he had time to think, to express wonder to Hassan as to what it could be, the tornado swept over the desert, carrying before it mimosa bushes and cacti, clouds of shining pebbles, the withered fragments of an old gum-tree, and the white bones of a dead camel. How his animal withstood the sharp and sweeping blast that darkened all around them, Malcolm Skene knew not; but he found his hands torn from the stirrup-leather, and himself flung furiously and helplessly amid the sand, which half covered him. After a time, gasping, with his throat, nostrils, and ears full of dust, he struggled to his feet and looked around him, and saw, already far distant, the sand-cloud borne away by the mighty wind, then in its wild career to some other quarter of the desert. Above him the sky was again cloudless; the air all still and clear; the awful and angry rush of the wind-storm was past. But where was Hassan Abdullah? A speck vanishing away in the far distance showed but too plainly where he had gone with all the speed his camel could achieve--a natural swiftness now accelerated by the extremity of fear; and in another minute even that moving speck disappeared, and Malcolm Skene found himself alone--guideless and ignorant of which way to turn his steps in the appalling solitude of the desert. What was he to do now? Follow in the route Hassan had taken, and which that wily personage no doubt knew led to some haunt of men, or abode of such civilization as existed there? Even that he could not do. The horizon showed no point to indicate where the speck he knew to be Hassan and his camel had vanished. Malcolm's alarm for the future exceeded his just anger and indignation for the present at this sudden and unexpected desertion; but action of some kind became necessary, and though apparently he could not be worse off than where he was, every step he took might be leading further from the path he should pursue to Dayr-el-Syrian--further from a well or succour, and nearer to 'dusty death.' After glancing at the trappings of his camel, he remounted and rode forward slowly, fain to suck for a moment even a hot pebble of the desert in hope to produce a little moisture in his mouth, while consulting a small pocket map he possessed.