farmhouses gladden the sight. Culture and desert, life and death, are placed in such close juxtaposition that the astonished traveller may well doubt his own eyes.
This contrast in the nature of the country which still forms the boundary between that of roving nomads and that of settled cultivators is defined by the same Great Wall which we had seen at Kalgan and Ku-peh-kau. Hence it continues westwards over the mountains bordering the plateau, passing round the south of Ordos, and abutting on the Ala-shan mountains, which form a natural barrier to the desert. From the southern end of the last-named range, the Great Wall continues along the northern border of the province of Kan-su, past the towns of Lang-chau, Kan-chau, and Suh-chau to the fortress of Kia-yui-kwan. The Great Wall (if we can call it by such a name here) bears no resemblance to the gigantic edifice near Peking. Instead of an immense stone building, all we saw on the border of Kan-su was a mud wall, greatly dilapidated by time. A short distance to the north of it, about three miles and a half apart, stand clay-built watch-towers twenty-one feet high, by about as much square at the base, now entirely deserted, but formerly garrisoned by ten men, whose duty was to signal the approach of the invader. The line of watch-towers is said to have extended from the province of Hi to Peking itself, and news was conveyed by it with marvellous rapidity. The signal was smoke which rose from the summit of the tower, a fire
