DEPARTMENT OF TERRESTRIAL MAGNETISM. 335 



ment carried by the expedition was supplied by the United States 

 Signal Corps. 



One of the vital problems in connection with atmospheric-electric 

 and telephonic work in polar regions is the securing of suitable batteries 

 for operation at low temperatures. Much valuable assistance was 

 rendered in this connection by the Bureau of Standards, which sup- 

 plied a large amount of the data upon which final selection was based. ^ 



7. Miscellaneous. — The Department has continued to cooperate 

 with the Radio Laboratory of the Bureau of Standards in its study of 

 the ''swinging" of radio signals on short wave-lengths, especially by 

 making it possible for the Bureau to secure copies of all available 

 atmospheric-electric records suitable for the work in hand. 



The chief of the section, in accordance with instructions from the 

 Director, assumed charge of the instrument shop for portions of 

 February, March, and July, during temporary absences of Mr. 

 Fleming on official business. 



For publication work see abstract, pages 354-356. 



Valuable assistance has been rendered in the work of the section by 

 Dr. G. R. Wait, assistant physicist, and Mr. C. M. Little, assistant 

 observer. Dr. Wait was transferred to the Magnetic Survey Division 

 on July 18, preparatory to his departure to assume charge of the 

 Department's observatory at Watheroo, Western Australia, where he 

 will make the initial installation of the observatory atmospheric- 

 electric equipment referred to on page 333. During the months of 

 February, March, and April, approximately half of Dr. Wait's time 

 was devoted to work on the sine galvanometer under Dr. Barnett. 



ADMINISTRATIVE DIVISION.^ 



Line integrals of the magnetic force. — Line integrals of the Earth's 

 magnetic force along various parallels of latitude on the surface of the 

 Earth were computed in connection with the Director's investigations 

 concerning vertical currents (see pp. 347 and 348) . Material assistance 

 in this work was given by IVIr. G. H. Keulegan, temporarily engaged as 

 assistant physicist to December 31, 1920. The line integral of the 

 magnetic force along the sub-antarctic track of the Carnegie, December 

 6, 1915, to April 1, 1916, was also computed, with the assistance of Mr. 

 C. R. Duvall, based entirely upon the Carnegie results. The com- 

 putation along the ship's track was somewhat complicated by the 

 number of magnetic stations made during a day, which necessitated 

 deducing the course and distance between stations selected, one for 

 each day (preferably the daily dip and intensity station), and then 

 reducing the various declination results of the day to these stations; 



^The investigations made by the Bureau are described in a paper on "The Electromotive 

 Force of Cells at Low Temperatures," by G. W. Vinal and F. W. Altrup. J. Wash. Acad. Sci., 

 V. 12, 1922. 



^From the report of Vv. J. Peters, in charge of the di%'ision. 



