THIRTY THOUSAND MILES 

 IN CHINA 



CHARLES KEYSER EDMUNDS, PH.D. 



President of Canton Christian College and Observer- 



in-Charge Magnetic Survey of China, Carnegie 



Institution of Washington, 1906-1917 



Coming to China fourteen years ago, after several years 

 of experience as a physicist in the field as well as in the 

 laboratory and classroom in America, I naturally desired to 

 exercise the same dual functions in China. Urged by the 

 Editor, I presume to recite some aspects of such field work 

 as the interims in my increasing scholastic duties and 

 absences in America have allowed. 



Among the many problems which China faces to-day, 

 some of the most pressing are of a physical nature, such as 

 reforestation, control of rivers and canals to prevent floods, 

 construction of railways, development of mines, and many 

 others of a similar sort. In connection with the surveys 

 which are necessary in any comprehensive or co-ordinated 

 development along these lines, it is highly desirable that the 

 magnetic field of the earth be known as accurately as possible 

 throughout the country. For it is with the aid of the 

 compass that the most rapid and economical surveys can be 

 made. Hence the proper corrections to apply to compass 

 and dip needle pointings on land are of value to surveyors 

 and railroad and mining engineers, just as they are to the 

 mariner for sea areas. 



As the reputed inventors of the compass for use on both 

 land and sea, it is quite appropriate that the Chinese after 

 a long period of arrested development along such lines, 

 should have the assistance of scientists from the West in 

 securing as soon as possible an accurate knowledge of the 

 magnetic elements throughout their territory in which these 

 physical developments are being inaugurated and throughout 

 the adjacent seas on which so many Chinese risk their lives. 



Besides these practical applications, a detailed know- 

 ledge of the earth's magnetic field is essential for any 

 adequate conception of the cause or causes of such magnet- 

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