quarter of the fourth century A. D. In this connection we will consider only this middle branch.
In 1914., Sir AUREL STEIN succeeded in tracing the course of the ancient road between Lou-lan and the old Yü-men-kuan (situated NW of Tun-huang), i. e. the desert part of the Road of the Centre. It makes a detour to the north to avoid the largest expance of the salt-crust which marks the old extent of Lop-nor, but it has nevertheless to cross it for a stretch of about 3o km.
The route traced by STEIN was not the only possible one. A short-cut across the salt-crust along a line running SE—NW and followed by Mr. CHEN in 1931 (cf. the map Hörner 1935, Fig. 2) probably affords easier going than STEIN'S route, because it touches several "islands" in the salt-crust. That it was used also in Loulan's time is made probable through the finds discussed on p. 168. Although even this short-cut has six waterless stages.
The Road of the Centre was the shortest of the three branches of the Silk Road. The advantage of its being shorter than the rest was lessened by the extreme difficulty of crossing such a wide waterless desert. Above all, the big petrified sea-bed with its hard salt-crust must have presented a terrible obstacle to all travellers and their beasts of burden. Nothing could be more dead than this desolate salt expanse. It is an absolute desert, from which every form of life is banished.
Not much experience of desert travelling is needed to understand that the only means of conveyance in ancient days must have been camels, and that the journey along the 190 km. long desert route found by STEIN was possible only in winter. In the hot season this route is and was absolutely impassable.
Some observations made by HEDIN during his motor trip through the southern hills of Pei-shan in the winter 1934-35 seem to point to the existence of now deserted roads in this mountain region. The northern branch of the Silk Road, which was opened in the period 1-5 A. D. passed through the Pei-shan region, and so do several roads running N—S between Tun-huang and Hami, and it may have been cairns of these roads that HEDIN came across. It is very likely however, that the caravans of ancient days, when travelling from Tun-huang to Lou-lan, followed some northerly route going inside the low Pei-shan ridges, where there may have existed some springs and even wells. Such a route was probably traf f icable for a longer period of the year than STEIN'S road. But even here traffic must have been practically nil during the hot summers — as is the case on all Central Asian desert distances of any length where rest-houses with provisions for the animals do not exist.
I am not sure that these desert routes were chosen just because of their shortness. Time was certainly of still less value 2000 years ago than it is now in this part of the world; and every sensible trader avoids deserts, if possible. When the big overland traffic started, the Hsiung-nu were blocking the more easily negotiated