We pushed on at a steady pace over the rough ground; and as I surveyed the scene from my elevated position on the camel's back, I could not help contrasting this primitive style of travelling with that with which I had been conversant a few months before. Instead of whirling along the summit of an embankment, or through a horizontal well miles deep, in a machine that always reminded me of a disjointed dragon, at the rate of some fifty miles an hour, here I was leisurely swaying to and fro on the back of the slowest beast that man has ever tamed, in the midst of a crowd loosely scattered over the country, some on foot, some in the saddle--not seeking to keep any determinate track, but following a general direction by the light of the stars, which shine with warm beneficence overhead. There is no sound to attract the ear, save the measured tread of the caravan, the occasional "_Isa! Isa!_" of the drivers, the hasty wrench with which our camels snatch a mouthful of some ligneous plant that clings to the stony soil, the creaking of the baggage, or the whistling of the wind that comes moaning over the desert. These are truly moments in a man's life to remember; and I shall ever look back to that solemn night-march over the desert, which my pen fails to describe, with sentiments of pleasurable awe. This night we moved at comparatively a rapid pace--nearly three miles an hour; for there was scarcely any temptation to the camels to linger for browsing purposes, and the drivers seemed desperately anxious to get over as much ground as possible at once. At first all went well enough; and now and then even, the blacks, who were on foot, braved the Hamadah with a lively ditty--celebrating some Lucy Long of Central Africa. But by degrees these merry sounds ceased to be heard; and the hastily-moving crowd of the caravan insensibly stretched out into a longer line. The poor women were beginning to knock up, and several fell at times from mere exhaustion. We proceeded, however, without stopping, for eleven hours, and after a long, dreary night indeed, halted at five in the morning, having reached the encampment of our German friends. The dawn soon lighted up the waste, and enabled us to see that it was a level plain of hard red earth, scattered over with pebbles and loose pieces of limestone mixed with flint. The Hamadah was very cold in the night, the wind being from the north. Dr. Overweg does not think that the plateau is more than fifteen hundred feet above the level of the sea; but it may be two thousand, and a little more in some places. By day it is hot enough; and as there is little to be observed on these vast, elevated stretches of stony desert, I thought it best to continue my original plan for three whole nights. To spare one's self is the great secret of Saharan travelling; and there is, after all, not much to observe in this desolate region.