340 TO THE SU-LO-HO DELTA [Chap. IX
This fact and the great distance, over two hundred miles, from the base at Tun-huang must have vastly increased the difficulties of the problem of supplies and transport, so far as the western portion of the old route to Lou-lan was concerned. Yet, although we shall never know the exact details of the organization, it is certain that the problem had been courageously faced ever since the Emperor Wu-ti first launched his trade missions and then his expeditions to the Târim basin and beyond. As the greatest obstacle of all was, no doubt, the absence of water, it seems safe to assume that the fullest possible use was made, on this inhospitable tract, of camel transport, as being least in need of regular watering. That camels were particularly plentiful in Lou-tan is attested by the notice of the territory in the Former Han Annals.12 The employment of large trains of camels for the carriage of water, provisions and fuel would undoubtedly offer the best means of overcoming the obstacles to traffic presented by this wholly waterless ground. But it must be remembered that during the four hottest months of the year, i. e. from May to August, camels could not possibly be worked in the Lop basin without enormous losses 13
Account should also be taken of the probability that a considerable proportion of the traffic along the route was conveyed in horse-, mule-, or ox-drawn carts, a mode of transport for which the Chinese all through Kan-su and Central Asia still retain a time-honoured attachment, and the use of which is attested by Chinese documents from the Lou-tan site.l4 It offered undoubted advantages in the matter of ease, and its employment would encounter no extraordinary obstacle on either side of the wholly waterless portion of the desert. But what difficulties it necessarily involved on the five long marches without water is revealed by a simple calculation. More than one-half of the useful load of a mule- or horse-drawn cart would be absorbed by the water and fodder alone needed for the animals, while the rest would barely allow for the carriage of four passengers with a minimum of baggage, or of the water and rations required by four mounted men.15
Use of camel transport.
Probability of cart traffic.
12 Cf. Wylie, J. Anthrop. Inst., x. p. 25 : `They have asses, horses, and many camels.' For references to camels in Lou-lan documents, see Chavannes, Documents chinois; Nos. 839-41.
13 The dangers attending the working of camels in the plains of the Tarim basin during the hot season were brought home to me very sadly by the subsequent loss of most of the fine animals with which my caravan had started from Kashgar in June, 1906 ; cf. Desert Cathay, i. pp. 220, 26o. Yet they had been worked only for a comparatively small number of marches, and had all the relief that ample grazing and frequent halts at the comparatively cooler foot of the hills could give.
The daily maximum temperatures during June and July in the Lop desert may rise to heights that could well hold their own against those of the Panjâb plains and of Sind at the same season. Of course the night temperatures would probably be much less.
14 For the mention of oxen carriages ' and carts, cf. two Chinese records among Dr. Sven Hedin's finds at L.A., in Conrady, Chinesische Handschrijtenjunde Sven Hedins, pp. 81, 88. These documents do not make it clear where the vehicles were to be used.
The fragmentary document No. 755 from L.A. vi. ii, Chavannes, Documents chinois, p. 164, refers to a ` cart and oxen ' that a petty official is dispatched to examine and try in camp. Whether they were to be employed locally or for a distant journey we are not told,
15 This calculation is based on the figures I obtained from Col. Scott-Moncrieff's R.E. Field Service Pocket-book (2nd ed.). This indicates 8 gallons as the daily ration for a horse, mule, or ox, with an approximate weight of 8o lb. To this may be added a minimum of 8 lb. for fodder per diem. Thus, assuming that a two-horsed cart had to cover a distance of 125 miles in the course of five days, with four halts between at places to which water, &c., would have to be brought along from the starting-point, not less than 640 lb. would have to be carried in the weight of water alone, with about 12o lb. added for the weight of the cask. If we take into account the weight of fodder rations for the same four stages, about 64 lb., provision for the needs of the draught-animals would take up 824 lb., out of a total useful load of 1,344 lb.
During the winter months the amount of water might, perhaps, be reduced somewhat below the regulation ration. But on the other hand at that season and well into the spring, when freezing Burâns occur, the carriage of adequate fuel for the warmth needed by men would materially increase the load.
It has occurred to me, while thinking over this commissariat problem both on the ground and since, that the use of camels as draught-animals might considerably facilitate its solution ; for assuming that the proportion between the useful load which a camel can draw in a cart and that which it can carry on its back is approximately the same as in the case of a horse or mule, viz. 4 : I, it is obvious that a great deal more weight could be spared in carts for the transport