LAND MAGNETIC OBSERVATIONS, 1905-1910. 



INTRODUCTION. 



The present publication is the first of a series by the Department of Terrestrial 

 Magnetism of the Carnegie Institution of Washington bearing the general title 

 "Researches of the Department of Terrestrial Magnetism." Under this head it 

 is proposed to publish the results of the various operations and researches conducted 

 by this Department. While the subject treated will be chiefly that of the Earth's 

 magnetism, from time to time memoirs will appear on other more or less closely 

 allied subjects, such as atmospheric electricity, for example. The volumes on the 

 work done aboard the magnetic survey vessels, the Galilee, 1905-08, and the 

 Carnegie, 1909-, besides giving the results in terrestrial magnetism and atmos- 

 pheric electricity, may set forth also the results of observations in atmospheric 

 refraction, etc. In brief, certain volumes or portions of them may be on other 

 subjects than terrestrial magnetism proper. 



Each volume will have a subtitle setting forth briefly its special contents. 

 Thus the present volume, "Land Magnetic Observations 1905-1910," contains the 

 results of all magnetic observations made on land by the Department from the 

 beginning of its observational work in February 1905 to the end of December 1910, 

 practically six years' work. Future volumes will contain the land work subsequent 

 to 1910, as also the observations made on the Galilee, 1905-08, and next on the 

 Carnegie, 1909-. 



The Department of Research in Terrestrial Magnetism was founded on April 1, 

 1904, one of its special objects being the acquirement of the necessary data for a 

 general magnetic survey of the globe. The chief endeavor is to secure magnetic 

 results in the regions where most needed and where there are no organizations 

 prepared to undertake the work. Where magnetic surveys are in progress under 

 competent direction and where the prospects for early completion are favorable, 

 the Department confines its work to the observations necessary for the proper 

 correlation of results obtained with different instruments and by diflferent methods 

 and renders such assistance to organizations as may be required. While the 

 Department has been able to extend special aid at times to certain organizations, 

 in order that their object might be effectively and expeditiously carried out, it is 

 a pleasure to record and gratefully acknowledge here the cordial and valuable aid 

 it has itself received from magnetic institutions in all parts of the world, as well as 

 from the governmental and diplomatic representatives of the countries visited. 



The publication of the results given in the present volume was necessarily 

 delayed by the many problems presented when magnetic observations made over 



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