DEPARTMENT OF TERRESTRIAL MAGNETISM.* 



L. A. Bauer, Director. 

 GENERAL SUMMARY. 



The chief operations and results of the Department during the 

 period November 1, 1912, to October 31, 1913, may be sunomarized 

 as follows : 



MAGNETIC SURVEY OF THE OCEANS. 



The second cruise of the Carnegie, begun at New York on June 20, 

 1910, was very nearly concluded at the end of the present fiscal year. 

 She has been in continuous commission for somewhat over three years, 

 Mr. W. J. Peters having been in command throughout. During 

 this period the Carnegie has been making a complete circunmaviga- 

 tion of the globe, the aggregate length of the cruise being over 92,000 

 miles, t 



Accurate magnetic data have now been obtained by the Depart- 

 ment in all the oceans near the tracks usually followed by vessels, 

 between the parallels of 50° north and 50° south. The total length 

 of the cruises along which these data have been secured, during the 

 period 1905-1913, was 60,000 miles for the Galilee (1905-1908), and 

 for the first and second cruises together of the Carnegie (1909-1913) 

 100,000 miles, or of the two vessels, 160,000 miles. 



Owing to the promptness with which the results of chief interest 

 to the mariner were made known, it has been possible for hydro- 

 graphic estabhshments to revise or issue corrections to their magnetic 

 charts before the completion of the present cruise. It is gratifying 

 to report that smaller chart errors than was the case on the initial 

 cruises of our vessels are now being found in parts of the oceans 

 chiefly traversed. 



The future work of the Carnegie will consist in obtaining magnetic 

 data either in the areas not yet covered or where the past observa- 

 tions had to be meager because of cloudy or stormy conditions 

 encountered. She will at the same time intersect her previous tracks 

 as frequently as possible in order to obtain at these points the amount 

 of annual change in the magnetic elements — data urgently needed 

 in order that magnetic charts may be kept corrected up to date. An 



*Address: The Ontario, Washington, District of Columbia. Grant No. 827. $110,263 

 for investigations and maintenance during 1913, and $100,000 for purchase of site and 

 erection of Office and Laboratory Building. (For previous reports see Year Books 

 Nos. 3-11.) 



fThe Carnegie returned to Brooklyn on December 19, 1913. 



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