and our topographical work. Colonel (now SIR SIDNEY) BURRARD, R.E., K.C.S.I., F.R.S., first as Superintendent, Trigonometrical Surveys, and later as Surveyor General, showed the keenest interest in my explorations and used every opportunity to encourage and guide our labours in the field by his experienced advice. He greatly facilitated the subsequent preparation of their cartographical record in the Trigonometrical Survey Office, Dehra Dun, as now presented in the atlas of ninety-four map sheets, on the scale of four miles to the inch, which forms volume V of this publication.
In my Notes on Maps illustrating- explorations in Chinese Turkestan and Kansu which accompanied much-reduced reproductions of these maps as published in the Royal Geographical Society's yournal, 1911,4 detailed information has been given as regards the methods used in our surveys (which comprised triangulation and astronomical observations besides regular plane-table work on all routes, whether followed with my topographical assistant or by either of us alone) ; as to my direct supervision of the work in general, the phonetic transliteration adopted for the record of local names, etc., as well as regards the system used for the final compilation of the map sheets.6 Of these reduced maps the one showing in a single sheet the total area surveyed on this journey, on the scale of 1 : 3,000,000, has with the kind permission of the Royal Geographical Society been reproduced as a kind of Index map to the Atlas. Incidentally it may serve as an apt illustration of the great extent of the ground over which the devoted exertions of my assistants made it possible to carry our topographical labours. Use has been made also of this general map in order to indicate by references on superimposed ` tracings ' the chapters in which information of geographical interest is given on particular areas, and thereby to facilitate the use of my printed record by geographical students.
For the successful attainment of my topographical programme it was of the greatest value that I was provided from the first in Rai RAM SINGH, now Sub-Assistant Superintendent, Survey of India, with a surveying assistant of tested ability and familiar with Central-Asian mountains and deserts from previous expeditions, including my own first journey. When reasons of health connected with the hardships of our winter campaign 1906-7 obliged him to return to India, Sir Sidney Burrard took care to replace him by Rai Bahâdur LnI. SINGH, a surveyor of exceptionally wide experience and one whose eagerness for hard work under conditions however trying I have never seen surpassed. I found in both surveyors willing and always reliable helpers for many other practical tasks. It has been a source of sincere gratification to me that the Royal Geographical Society, when it honoured me on my return from this journey with the Founder's Gold Medal, did not fail to recognize the services of those two valiant assistants by appropriate awards.
' See The Geographical Journal, 191r, pp. 275-80.
I may note here that the results of the surveys carried out on my first and second expeditions have been carefully embodied, together with the cartographical results of my third Central-Asian journey (1913-15), in a final atlas of forty-nine sheets on the scale of 1: 5oo,000, which is now approaching completion at the Trigonometrical Survey Office, Dehra Dun. This new atlas thus comprises the whole of the topographical work accomplished during my Central-Asian explorations, and has been prepared with improved methods of technical reproduction. It is to be accompanied by a Memoir from my pen giving full details as to the materials used for its construction and including triangulation charts and complete lists of astronomically determined positions.
In this final map publication it has been my endeavour to rectify any inaccuracies which our subsequent surveys have brought to light in the cartographical representation of certain
features on ground comprised in the 4 miles to inch sheets, as well as to introduce greater consistency in the spellings of local names than was possible at the time when those map sheets were being prepared at Dehra Dun (1909—II).
Owing to technical reasons connected with my absence in England during that period, it was impossible for me to revise the original drawings for the sheets or to examine more than one proof of the sheets as produced in their final stage showing the hill-drawing and colours for the different kinds of ground (cultivation, sandy tract with vegetation, drift-sand desert, etc.). Other reasons of a technical character, which cannot be set forth here in detail, account for a certain roughness of execution. Nevertheless I believe that these sheets, if tested on the spot, will be found well able to bear comparison as regards the essential feature of accuracy with any maps previously available for ground of corresponding character in Central Asia.