( 141 ) 



describing the observed phenoiiiena, lay down quite definite conceptions 

 regarding- certain conditions and configurations of matter in the solar 

 atmosphere, by whicli the observed distribution of the light in the 

 image of the Sun is assumed to be produced. In Ihc cited publication they 

 put fortii the working hypothesis that Ihe "calcium-flocculi" or bright 

 regions showing themselves all over the image of liie Sun when it 

 is photographed in so-called calcium light, arc colunms of calcium 

 vapour rising above the columns of condensed vapours of wliich the 

 photospheric "grains" are the summits (I.e., p. 15). This hypothesis, 

 though at first proposed mainly as a guide to further research (I.e., 

 p. 13), has been subsequently^) employed by the same authors with much 

 less restriction as the basis on which the photographs ought to be 

 interpreted. 



The great authority of Hale and of such critics as W. S. Lockyer, 

 J. EvERSHED and others who, in abstracts from the work of Hale and 

 Ellerman, concur in most of the interpretations there given, might 

 cause the value of those ideas to become overestimated and extended 

 beyond the original intention of the authors. 



It is not superfluous, therefore, to show how we may quite as well 

 account for all the new phenomena thus far revealed by the spectro- 

 heliograph, if we start from the entirely different conceptions of 

 the Sun's constitution, which the consequences of ray -curving in non 

 homogeneous media and of anomalous dispersion of light in absorbing 

 vapours have suggested to us. 



Both these circumstances are left absolutely out of consideration 

 by Hale and Ellerman. Their conclusions are all founded on the 

 erroneous supposition that the monochromatic ligiit by which their 

 images of the Sun are photographed, has travelled from the source 

 in straight lines, and that they are right, accordingly, in supposing 

 light-emitting masses of calcium vapour to exist in the exact directions, 

 along which calcium-radiations seem to reach us. In making this 

 supposition they fall into the same error as one who would assume 

 the refracting facets of the crystal globe of a burning lam]) to be 

 independent sources of light. 



Our new explanation of the spectrolieliographic results will be founded 

 on the hypothesis that the Sun is an unlimited mass ofgas in which 

 convection currents, surfaces of discontinuity and vortices are conti- 

 nually forming under the influence of radiation and rotation, so that 

 the various composing elements are mingled as conq^letely as nitrogen 



1) G. E. Hale and F. Ellerman, "Calcium and Hydrogen Flocculi," Astro- 

 physical Journal XIX, p. 41—52. 



