It was my fortune, by the way, to encounter one of the _huboubs_, or sand-storms, for which the Sudan is famous. To give an adequate idea of it, however, is as impossible as it is to describe any other overwhelming phenomenon of nature. Far off across the desert we saw it approaching at the speed of a galloping horse—a great fleecy, yellowish-brown cloud which looked for all the world like the smoke of some gigantic conflagration. A distant humming, which sounded at first like the drone of a million sewing-machines, gradually rose into such a roar as might be made by a million motor-cars, and then the storm was upon us. The sand poured down as though shaken through a sieve; the landscape was blotted out; the sun was obscured and there came a yellow darkness, like that of a London fog; men and animals threw themselves, or were hurled, to the ground before the fury of the wind, while a mantle of sand, inches thick, settled upon every animate and inanimate thing. Then it was gone, as suddenly as it had come, and we were left dizzy, bewildered, blinded, half-strangled, and gasping for breath, amid a landscape which was as completely shrouded in yellow sand as an American countryside in winter is covered with snow. Under any circumstances a sand-storm is a disagreeable experience, but out on the desert, where the traveller's life frequently depends upon the plainness of the caravan trails, it ofttimes brings death in its train. It is a gratifying compliment to American mechanical skill that the running-time between Wady Halfa and Khartoum has been shortened four hours by the recent adoption of American locomotives, which run, fittingly enough, over American-made rails. In the construction of its trains the Sudan government has avoided the irksome privacy of the European compartment car and the unremitting publicity of the American Pullman by designing a car which combines the best features of both. The first-class cars on the Sudanese express trains contain a series of coupés, each somewhat roomier than the drawing-room in a Pullman sleeper and each opening into a spacious corridor which runs the length of the car. For day use there is one long cushioned seat running crosswise of each compartment, which at night forms the lower berth, the back of the seat swinging up on hinges to form the upper. Each coupé is provided with running water, a folding table, two arm-chairs of wicker, and an electric fan, without which last, owing to the almost incredible dust which a train sets in motion, one would all but suffocate. At several stations along the line are well-equipped baths, at which the trains stop long enough for the passengers hurriedly to refresh themselves.