346 ; REPORT—1883. 
On some Results of Photographing the Solar Corona without an 
Eclipse. By Wiu1am Hueains, D.C.L., LL.D., FBS. 
[PLATE XI.] 
[A communication ordered by the General Committee to be printed im extenso 
among the Reports. | 
Last December (1882) I had the honour of presenting to the Royal 
Society a note on ‘A Method of Photographing the Solar Corona with- 
out an Eclipse.’ In that paper I say :—‘ If by screens of coloured glass 
or other absorptive media the region of the spectrum between G and H 
could be isolated, then the coronal light which is here very strong would 
have to contend only with a similar range of refrangibility of the light 
scattered from the terrestrial atmosphere. It appeared to me by no means 
improbable that under these conditions the corona would be able so far to 
hold its own against the atmospheric glare, that the parts of the sky im- 
mediately about the sun where the corona was present would be in a 
sensible degree brighter than the adjoining parts where the atmospheric 
light alone was present. It was obvious, however, that in our climate 
and low down on the earth’s surface, even with the aid of suitable screens, 
the addition of the coronal light behind would be able to increase but in 
a very small degree the illumination of the sky at those places where it 
was present. ‘There was also a serious drawback from the circumstance 
that although this region of the spectrum falls just within the range of 
vision, the sensitiveness of the eye for very small differences of illumina- 
tion in this region near its limit of power is much less than in more 
favourable parts of the spectrum ; at least such is the case with my own 
eyes. There was also another consideration of importance; the corona is 
an object: of very complex form, and full of details depending on small 
differences of illumination, so that even if it could be glimpsed by the eye, 
it could scarcely be expected that observations of a sufficiently precise 
character could be made to permit of the detection of the more ordinary 
changes which are doubtlessly taking place in it. These considerations 
induced me not to attempt eye-observations, but from the first to use 
photography, which possesses extreme sensitiveness in the discrimina- 
tion of minute differences of illumination, and also the enormous advantage 
of furnishing a permanent record from an instantaneous exposure of the 
most complex forms.’ 
The photographs described in that paper were obtained with a reflect- 
ing telescope of the Newtonian form by Short, and the restriction of the 
light to the small range of refrangibility from about G to H was effected 
by the use of screens of coloured glass, or by a cell containing a solution 
of potassic permanganate. The photographs showed distinctly coronal 
appearances around the sun, and I was permitted by Captain Abney, 
F.R.S., who made a careful examination of the plates, to say that, in his 
opinion, the solar corona had been photographed on my plates with an 
uneclipsed sun. 
I purpose in this paper to give an account of some further experiments 
founded on the same method made during the spring and summer of the 
present year. 
I am indebted to Miss Lassell for the loan of a seven-foot Newtonian 
telescope made by the late Mr. Lassell. The speculum, which is seven 
