70 



E. WALTEE MAUNDER, F.E.A.S., ON 



obvious when the numbers of spot groups are considered than 

 when the areas are taken, since it is the small groups that die out 

 most easily. 



The " prominences or red flames seen round the circum- 

 ference of the sun seem to show a slight, yet quite distinct, want 

 of symmetr}^ of the same kind, the eastern prominences being 

 more numerous than the western, except in years when there 

 are very few prominences seen at all. 



The earth then has an influence, or, at least, an apparent 

 influence, over the sun, since the groups of spots are, on the 

 whole, considerably more numerous in the eastern half of the 

 sun's disc than they are on the western half, and a similar 

 relation is noticed in the case of prominences and of the total 

 spotted area. Now the central meridian of the sun, dividing 

 the eastern half from the western, is distinguished from any 

 other solar meridian only in this — that it is central as seen 

 from the earth. It is defined entirely by the position of the 

 earth, not by any solar feature. Every part of the sun's surface 

 passes in its turn under that meridian. If then spots and 

 prominences form and dissolve, wax and wane, with some 

 numerical relationship to the central meridian, they do so with 

 a numerical relationship to the position of the earth as such. 

 And that implies a causative relation between the position of 

 the earth and this want of symmetry between the eastern and 

 western segments of the sun as seen from it. 



Yet the relation may be merely apparent. First of all, this 

 disproportion betv/een east and west is not very large. It is 

 important therefore to increase — to increase very greatly — the 

 statistics in question before we can be quite sure that we are 

 not dealing with a relationship merely accidental and temporary. 

 It may have held good for the period covered in Mrs. Maunder's 

 inquir}^, but may not hold equally good for other periods. Or a 

 different way of dealing with the same statistics might have 

 led to a different conclusion, and such re-examination of the 

 statistics from different points of view must be made, and, no 

 matter how great the labour, will be made when the opportunity 

 serves, to ascertain if the discordance between east and west 

 always holds good or not ; and if not, what are the conditions 

 under which it disappears. And if it always holds good, what 

 then ? Even in that case, it still may be merely an effect of 

 our standpoint, some effect, if not of perspective, yet of something 

 analogous. But we may not assume that this, or its contrary. 



