HISTORY OF THE SURVEYS
SECTION I.—GENERAL CHARACTER OF THE TOPOGRAPHICAL WORK
The main facts concerning the surveys effected on my three Central-Asian expeditions and many of the more notable incidents and results which attended them have been already recorded in the Personal Narratives ' and `Detailed Reports ' published by me of the first two journeys 1 or, as regards the third, in the fairly comprehensive preliminary account printed in the Royal Geographical Society's Jonriaal. 2 I shall accordingly restrict myself here to notes on the character and range of the surveys made of each journey; on the assistance available for the topographical work of each, and on the routes along which this work was carried, distinguishing the routes upon which the surveys were effected under my personal supervision from others where the operations were conducted by my assistants or myself alone.
. Before however recording these details for each successive expedition it will be convenient here to indicate essential points regarding the methods which
Methods in surveys. were uniformly observed in all our surveys. As already stated above,
these methods were-the same as those employed by the Survey of India for reconnaissance survey ' work. They implied continuous plane-tabling along all routes followed, supplemented throughout by astronomical observations for latitude and by triangulation rendered possible in particular areas by proximity to previously fixed points, by the configuration of the ground, available time and similar considerations.
Except on the journey of r900-Ol when a scale of 8 miles to 1 inch was used, the
surveys were on the scale of 4 miles to 1 inch, this having proved by experience on the ground to be the most convenient for adequate record of topographical detail under our conditions of travel. On mountainous
ground no efforts were spared to place plane-table stations on commanding heights above passes and route lines,. maximum elevations of nearly 20,000 feet being climbed by us in the K`un-lun for this purpose and of over 16,000 feet at numerous points of the Pamir and Nan-shan ranges. In the great plains of the Tarim basin and in the similar drainageless deserts eastwards, the flatness of the ground, the absence of recognizable landmarks and the peculiar dust-laden condition of the atmosphere, persisting for prolonged periods, made it very often impossible to fix positions by intersections or triangles. On this ground the exact measurement of distances which the use of the cyclometer invariably carried on the second and third expeditions permitted, was essential for the plane-table traverses.
For the purpose of securing points to check these traverses, astronomical observations
for latitude were made by my assistants with a 6-inch transit IheodoLatitude observations, lite at frequent intervals when atmospheric conditions and available time
permitted. These observations were beset with serious difficulties, both on account of climatic conditions and the rapidity of movement necessitated by other scientific tasks and the wide extent of difficult ground to be covered. Prolonged periods of
Scale, et e., of plane-
' See for the journey of 1900-01, Sand.buried Ruins of Khotan. 'Personal Narrative of a journey of archeological and geographical exploration in Chinese Turkistan', London, 1903 (second edition, 1904); and Ancient Shotan, 'Detailed Report of archeological explorations in Chinese Turkistan, carried out and described under the orders of H. M. Indian Government by M. Aurel Stein', Clarendon Press, Oxford, 1908 (two vola. 4ro).
For the expedition of 1906-08, see Ruins of Desert Cathay, 'Personal Narrative of explorations in Central
Asia and westernmost China,' by M. Aurel Stein, London, 1912 (Macmillan & Co., two vols. 8vo) and Serindia, ' Detailed Report of explorations in Central Asia and westernmost China carried out and described under the orders of 11. M. Indian Government by Aurel Stein K. C. I. E.,' Clarendon Press, Oxford, 1921 (five vols. 4to).
2 See A Third Journey of exploration in Central Asia,1913-16, by Sir Aurel Stein, in The Geographical Journal for August and September, 1916, xlviii. pp. 97-130, 193-229.