“The long, or endless wall, as it is commonly called,” says our traveller, who has given the best account I have yet met with of this prodigious undertaking, “encompasses all the north and west parts of China. It was built about six hundred years ago by one of the emperors, to prevent the frequent incursions of the Mongols, and other western Tartars, who made a practice of assembling numerous troops of horse, and invading the country in different places. The Chinese frontiers were too extensive to be guarded against such bold and numerous enemies, who, after plundering and destroying a wealthy country, returned to their own loaded with spoils. “The Chinese, finding all precautions ineffectual to put a stop to the inroads of such barbarians, at last resolved to build this famous wall. It begins in the province of Leotong, at the bottom of the bay of Nankin, and proceeds across rivers and over the tops of the highest mountains without interruption, keeping nearly along the circular ridge of barren rocks that surround the country to the north and west; and after running southward about twelve hundred English miles, ends in impassable mountains and sandy deserts. “The foundation consists of large blocks of square stones laid in mortar; but the rest of the wall is built of brick. The whole is so strong and well built as to need almost no repair, and in such a dry climate may remain in this condition for many ages. Its height and breadth are not equal in every place; nor, indeed, is it necessary they should. When carried over steep rocks, where no horse can pass, it is about fifteen or twenty feet high, and broad in proportion; but when running through a valley, or crossing a river, there you see a strong wall, about thirty feet high, with square towers at the distance of a bowshot from one another, and embrasures at equal distances. The top of the wall is flat, and paved with broad freestones; and where it rises over a rock, or any eminence, you ascend by a fine easy stone stair. The bridges over rivers and torrents are exceedingly neat, being both well contrived and executed. They have two stories of arches, one above another, to afford sufficient passage for the waters on sudden rains and floods.”[6] Footnote 6: