CHAE PERL 
TOPOGRAPHIC SURVEYS, 
By R. H. SARGENT. 

INTRODUCTION. 
Topographic surveys were undertaken by the Carnegie Expedition to 
China for the purpose of producing base maps, which should exhibit the 
features of the country in a reliable manner and on a large scale, and 
which might be used to illustrate detailed geological studies. It was pro- 
posed that there should be made a contour map, controlled by triangula- 
tion and checked by astronomical observations; the contours to be based 
on accurate determinations of altitudes and to be drawn to represent 
expressively the actual forms of topographic features. So far as was 
practicable under the conditions of our work in China, these requirements 
were met. In certain districts, however, triangulation was not possible, 
and it became necessary to resort to stadia surveying; and in the canyons 
of Shen-si the view was limited to the route traversed. The conditions 
under which the surveys were executed, and the checks which were secured 
on the accuracy of the work are more fully explained in the following 
paragraphs. Inspection of the atlas accompanying the report will best 
show the results obtained. 
Two small areas were surveyed in Shan-tung, during the autumn, by 
Mr. Willis before the topographer joined the party. They are represented 
in the Ch’ang-hia and Sin-t’ai sheets, Plates XIII and XIV of this volume. 
The major part of the surveys falls into two widely separated sections. 
The one, comprising the first ten atlas sheets, extends from Pau-ting-fu 
in the province of Chi-li to T’ai-ytan-fu, Shan-si. (Plate IJ.) The second 
section, which is delineated in the ten remaining atlas sheets, extends from 
Chéu-chi-hién, Shen-si, to Wu-shan-hién, Ssi-ch’uan. (Plates VI and VII.) 
During the initial work at Pau-ting-fu I was fortunate in having the 
assistance of Captain Turner, detailed from the force of the British Intelli- 
gence Bureau, North China Command, by Colonel A. W. S. Wingate. By 
order of Colonel Wingate, a Hindoo sergeant, Abdullah, trained in the 
British method of military reconnaissance surveying, accompanied us and 
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