THE 



AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES.] 



Aet. XX. — The Magnetic Theory of the Solar Corona ; by 

 Feank H. Bigelow. 



The hypothesis that the sun's corona is an appendage con- 

 trolled by a magnetic field, whose base is in a central nucleus, 

 and by an electric discharge radiation arising near the surface, 

 which together interacting upon small particles of electrically 

 charged matter arrange them in the observed curved rays, has 

 been making progress in recent years towards a firm theory.* 

 This view is so well known that we may pass at once to the 

 review of certain results of research which tend to sustain, if 

 not to confirm it. In my work, points were measured on pho- 

 tographs of the corona along the individual visible rays, and 

 discussed by the formulae applying to the lines of force sur- 

 rounding a spherical magnet, modified to allow for projection 

 on a plane passing through the center of the sun perpendicular 

 to the line of sight from the earth. The invisible bases of the 

 rays were located by tracing back their visible portions to the 

 surface of the sun, and they were found to lie in narrow belts, 

 one in each hemisphere, which were located about 30 degrees 

 away from the poles, the polar zones themselves being denuded 

 of rays. The equatorial and midlatitude zones were filled 

 with an interlacing tangle of lines not subject to further mag- 

 netic classifications. 



In the year 1892, Pupinf in America and EbertJ in Ger- 

 many produced coronoidal discharges in poor vacua, by placing 

 a small conducting body inside a glass globe covered with tin 



*The Solar Corona, Smithsonian Institution, 1889; this Journal, Nov., 1890, 

 July, 1891; Astron. Soc. Pac, No. 14, 1891, No. 16, 1891; Bulletin No. 21, 

 U. S. Weather Bureau, 1898. 



f This Journal, April and June, 1892. % Chicago Congress, 1893. 



Am. Jour. Sci— Fourth Series, Vol. XI, No. 64.— April, 1901. 



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