They now entered upon that vast table-land which was found by the Jesuits to be three thousand geometrical paces above the level of the sea, from which the mountains forming its southern boundary serve but as steps by which the traveller may descend to the low plains of China. The small undulations or eminences which break the uniformity of these vast steppes are covered with the rhubarb plant, which grows there spontaneously, and is propagated more rapidly by the aid of the marmot, which, burrowing in prodigious numbers at its roots, loosens the mould, and prepares it for the reception of the seeds. The roots are dug up for exportation by the Mongols, who carelessly bore holes through them, and hang them about their tents or on the horns of their sheep to dry. After passing the Tula, no river again occurred north of the Great Wall. The mode of travelling here resembles, in some degree, that which prevails in the deserts of Arabia and Africa, except that the walls are more frequent, and the danger from marauders little or none. Their food, after the first few days, consisted of mutton only; but as this was of an excellent quality, the circumstance was not considered as a great hardship. In the course of their journey they traversed a large plain, thickly strewed with transparent red and yellow pebbles, which glittered beautifully in the sun, and were said to be cornelians and yellow sapphires, being hard, and taking a fine polish. The few Mongols whom they found wandering with their flocks and herds over the waste, appeared more contented and happy than the possessors of the most fertile soil; and this being the primitive, the freest, and perhaps the most natural condition of man, the circumstance ought not to excite our astonishment. The mere act of locomotion is pleasant to man, and in pastoral tribes, accustomed to wandering from their infancy, it becomes a passion, the gratification of which is happiness. “On the 2d of November, about noon,” says Bell, “we could perceive the famous wall, running along the tops of the mountains, towards the north-east. One of our people cried out ‘land!’ as if we had been all this while at sea. It was now, as nearly as I can compute, about forty English miles from us, and appeared white at this distance.” The nearer they approached the mountains, the more were they astonished at the grandeur of this wall, which, as Voltaire very justly observes, makes no inconsiderable figure even upon the map of the world. “The appearance of it,” says our traveller, “running from one high rock to another, with square towers at certain intervals, even at this distance, is most magnificent.” In two days they arrived at the foot of this mighty barrier, and entered through a great gate into China. Here a thousand men were perpetually on guard, by the officers commanding whom they were received with much politeness, and invited to tea.