Page:Mongolia, the Tangut country, and the solitudes of northern Tibet vol 1 (1876).djvu/104

 so that he returns home in spring nearly empty-handed.

The land transport is so expensive that the price of brick-tea, which is exclusively consumed by the Mongols and inhabitants of Siberia, is increased by three times the cost of its production. A caravan takes from thirty to forty days on the road from Kalgan to Kiakhta, according to agreement with the contractor.

The tea chests are first covered with thick woollen cloths, which are afterwards stripped off, and the boxes sewn up in undressed hides, and despatched to European Russia, on carts or on sledges, according to the season of the year. Kalgan, as we have said, commands one of the passes through the Great Wall, which we beheld for the first time. It is built of large stones, cemented together with mortar. The wall itself is tapering, 21 feet high, and about 28 feet wide at the foundation. At the most important points, less than a mile apart, square towers are erected, built of bricks laid in mortar, as headers and stretchers. The size of the towers varies considerably, the largest measuring 42 feet on each side at the base, and the same in height.

The wall winds over the crest of the dividing range, crossing the valleys at right angles, and blocking them with fortifications. At such places alone could this barrier be of any advantage for defensive