THE ECLIPSE EXPEDITIONS. 
45 
and somewhat ruddy layer whose serrated surface may be seen 
far below the sinking prominence-matter. 
It is very probable, however, that the attempt which Mr. 
Brothers proposes to make to secure photographs of the corona, 
may cause the Sicilian party to be one of the most successful. 
His plan is to take a double series of photographs, one with a 
Sheepshanks’ equatorial belonging to the Astronomical Society, 
the other with a camera of his own, mounted upon the equa- 
torial and carried by the same movement. The camera 
pictures are intended to include a wide field, and it is far from 
improbable that the long coronal beams may thus, for the first 
time, be rendered visible in a photograph. I have had the 
advantage of a full discussion with Mr. Brothers of the plan he 
proposes to adopt, and I quite concur with him in thinking 
that, if weather alone be favourable, his operations are likely 
to be rewarded with a fuller degree of success than has yet re- 
warded attempts to photograph the corona. 
With regard to the long beams, I may remark that I regard 
them as among the most remarkable and significant phenomena 
presented to us by the corona. If the pictures which have 
been drawn by Gilman and others during recent eclipses be 
accepted as indicating the exact proportions of the dark and 
bright beams, a problem of great difficulty is presented to us. 
We might readily be misled by these radial beams to regard 
the corona as due to the passage of light-rays between the in- 
equalities of the moon’s surface, did we not attend to certain 
considerations which negative such a theory. Fr. Secchi, 
indeed, compares the corona to what is seen when the sun’s 
light is admitted into a darkened room through a nearly cir- 
cular opening imperfectly stopped by a circular plug, or through 
a circular opening imperfectly stopped by a nearly circular 
plug. Dr. Oudemann, also, has put forward a somewhat simi- 
lar interpretation of the coronal beams,* which he supposes 
due to the illumination of matter lying between the moon and 
earth. 
When such views are studied carefully for awhile, however, 
fatal objections become apparent. Let us suppose for a mo- 
ment — in order to give Oudemann’s theory a chance, so to 
speak — that we may neglect that matter of the. same sort which 
lies beyond the moon, and which, being illuminated more 
* Dr. Oudemann’s theory has lately been brought by Dr. De la Due under 
the notice of the Astronomical Society, but was not received very favour- 
ably. Of late, indeed, Dr. De la Hue has shown, as respects such theories, 
a consideration for the weak which appeals strongly to our sympathies as 
Englishmen, however far it may be from commanding our agreement as 
students of astronomy. 
