398 Proceedings of Royal Society of Edinburgh. [sess. 
slightly divergent. The portions of this streamer lying inside the 
edges fade away more rapidly than the sides, giving it somewhat 
the appearance of a swallow-tail. On the eastern side there are 
four streamers, one of which is, however, much longer and more 
conspicuous than the others, and is of about the same length as the 
edges of the western. The extreme ends of these four rays can be 
easily seen separated ; but, up to a distance of about half the sun’s 
diameter from the limb, they coalesce, forming together the bright 
inner region of the Corona. From a careful study of the photo- 
graphs, it seems to me that the eastern section of the Corona is made 
up of four roughly conical streamers, whose bases overlap one 
another to some extent at right angles to the line of sight. The 
western section, on the other hand, would appear to be composed of 
several streamers ; three, at least, can be made out, whose bases do 
not overlap, or do so only to a small extent. 
The polar regions present a great contrast to the east and west 
equatorial regions. They are much more contracted in extent 
along the limb, covering only about 45° at each pole, and instead 
of the long, far-reaching streamers, show only short feathery tufts, 
seven or eight in number at each pole. They curve away from 
the north and south poles of the sun’s axis, and collectively give 
one the idea of groups of feathers arranged as plumes. There is 
no appearance on any of these photographs of the dark rifts which 
have been found on some other photographs of this eclipse, and of 
some previous eclipses, such as 1896. The Corona surrounds the 
limb at all points, and in the spaces between the tufts the light 
fades away to so small an extent, and so gradually, that it is in 
some cases difficult to be sure that there is a division between the 
rays, without very careful examination of the negatives. 
As to the possibilities of the photographic method for giving 
large-scale pictures of the Corona, there is no doubt that it is only 
since the introduction of photography into the regular work of 
eclipse-observing that reliable pictures of the forms of the Corona 
have been obtained. Though several good photographs had 
previously been made by Dr De la Rue and others, it was not 
before the eclipses of 1870 and 1871 that really successful pictures 
of the outer regions of the Corona were obtained. In the latter 
year Mr Davis at Baikul and Mr Henessy at Dodabetta succeeded 
