268 CARNEGIE INSTITUTION OF WASHINGTON. 



The Director has continued his series of pubhcations in the journal 

 Terrestrial Magnetism and Atmospheric Electricity, on the physical 

 theor}^ of the Earth's magnetic and electric phenomena, having pre- 

 sented papers on the subject before various societies. In continua- 

 tion of this investigation, he also completed, with the assistance chiefly 

 of Mr. Duvall, a preliminary analysis of the general magnetic field 

 of the Sun as revealed by the published observations at the Mount 

 Wilson Solar Observatory. 



It was found that the solar magnetic field is as complex as that of 

 the Earth and that the distorting or disturbing systems which are 

 superposed upon a primary, simple magnetic field, follow laws very 

 similar to those disclosed in the study of the terrestrial magnetic 

 field. Thus, for example, the plane containing the magnetic axis of 

 the Sun is displaced in passing from the Northern to the Southern 

 Hemisphere in precisely the same direction eastward (in the direction 

 of rotation) as was found to be the case with the Earth's magnetic 

 axis. Accordingly, to give the requisite precision to the term ''mag- 

 netic axis," the region from which it is determined must be carefully 

 stated. The magnetic axis as determined from the published data 

 between the parallels 60° north to 60° south, for the four series of 

 observations between January 1912 and February 1913, was found 

 to be inclined about 9° to 12° to the axis of rotation. The same 

 angle of inclination for the Earth was 11.6° in 1885. 



The remarkably close analogies which thus appear to exist between 

 the magnetic field of the Sun and of the Earth, coupled with the fact 

 disclosed by Hale that "the polarity of the Sun corresponds with that 

 of the Earth, /. e., the north magnetic pole lies near the north helio- 

 graphic pole," may possibly indicate, since the direction of rotation 

 of the two bodies is the same, that the origin of both magnetic fields 

 will have to be referred finally to similar causes. In any case, the 

 fact that the Sun's magnetic field turns out to be as complex and as 

 irregular as that of the Earth, and that these apparent irregularities 

 follow similar laws for both bodies, would seem to strengthen the con- 

 clusion already reached in the investigation of the terrestrial mag- 

 netic field, that it msiy not be necessary to refer the cause of the non- 

 coincidence of the magnetic axis with the axis of rotation chiefly to 

 heterogeneity of structure of the bodies under discussion.* 



An examination and recompilation of the magnetic data secured 

 by Halley, 1698-1700, was also made by the Director, assisted by 

 Messrs. Ault and Wallis, and articles were published giving the results. 

 From April 21 to June 11 he was in Europe in the interests of the 

 Department. While there he concluded the appointments of a 

 physicist and two magnetic observers, and conferred with various 

 men interested in the work of the Department in Germany, Sweden, 

 and England, regarding certain cooperative work. 



*For abstract, see Journal of the Washington Academj^ of Sciences, December 19, 

 1913, vol. Ill, p. 513. 



