DEPARTMENT OF TERRESTRIAL MAGNETISM. 299 



report in Volume IV, Researches of the Department of Terrestrial 

 Magnetism (see p. 317). In that report the results of pre\ious eclipse 

 magnetic observations are also given. 



In consequence of the Department's appeals for cooperative mag- 

 netic and allied observations during solar ecUpses, valuable and exten- 

 sive data are now available not only for the study of eclipse magnetic 

 phenomena but also for other studies, as for example, the propagation 

 of magnetic effects over the Earth. With the results accumulated 

 since 1900 in all parts of the Earth, there would hardly seem any ques- 

 tion now that the magnetic condition of the Earth is appreciably 

 affected during a solar ecUpse. 



Miscellaneous investigations. — Various other investigations have 

 been completed and the manuscripts have been prepared for the special 

 reports in Volume IV, refeiTed to above, namely : Design and Consti-uc- 

 tion of Special Compass Variometers, by L. A. Bauer, J. A. Fleming, 

 and W. J. Petei-s; Results of Comparisons of Magnetic Standards, 

 1915-1920, by L. A. Bauer and J. A. Fleming; Magnetic Potential 

 and Field Components of Uniformly Magnetized Ellipsoids and 

 Homoeoids, by L. A. Bauer; Some Discussions of Ocean Magnetic Work, 

 by L. A. Bauer and W. J. Peters. 



Besides those whose names have already been mentioned, the fol- 

 lowing persons rendered assistance in the Division at various times: 

 F. Slocum, while Research Associate during summer of 1920; C. R. 

 Duvall, C. C. Ennis, and H. B. Hedrick, computers; H. D. Harradon, 

 librarian-translator; Emma L. Tibbetts, stenographer-computer; Eve- 

 lyn Morey, stenographer. 



ADMINISTRATIVE DIVISION.i 



Atmospheric refraction — This was a joint investigation with the 

 Director on the effects produced by differential refraction in the Earth's 

 atmosphere (see p. 298) . In the course of the investigation it was found 

 that differential refraction formulae given in Chauvenet's "Spherical 

 and Practical Astronomy," Volume II, page 456, are much more limited 

 in their appUcation than might be legitimately inferred from the test. 

 Chief assistance in computation was rendered by Dr. Hedrick. The 

 method used in the investigation and the conclusions reached were 

 subsequently verified by Dr. Fredrick Slocum, while Research Associate 

 (seep. 285). 



Dip-of-horizon observations made on the present cruise (VI) of the 

 Carnegie were tabulated, adjusted, and the summary of results from 

 1907 to 1920 was brought up to April 1920. Special investigations 

 of the results for Cruise VI were made by Dr. Slocum, who plotted 

 them in various curves to discover relations with the accompanying 

 data. The relation to dimensions of waves in particular was investi- 



'From Report of W. J. Peters, in charge. 



