268 
CAPTAIN W. DE W. ABNEY AND DR. A. SCHUSTER 
Intensity. 
Wave-length of 
prominence lines. 
Comparison. 
Dr. Huggins’ 
spectrum of a Aquilse 
4861 
H/3 (E) 
4473 
4471 (f) 
4340 
h 7 
4230 
4172-5 
4131 
4120 
4076 
4077 (Ca) 
4072 
4049 
6 
4025 
4022-5 
4000 
3997 
6 
3989 
1 
3968 
H 
3967-9 
4 
3955 
Ca 
1 
3933 
K 
3932-8 
3915 
2 
3888 
H* 
3862-5 
G 
3859 + 6 
3854 
3 
3834 
H/3 
3834 
6 
3816 
3816 
3807-5 
4 
3795 
h 7 
3795 
4 
3768 
Ha 
3767-5 
3 
3757 
3757-5 
5 
3746 
He 
3745-5 
6 
3730 
3730 
G 
3718 
H n 
3717-5 
6 
3708 
Ho 
3707-5 
5 
3699 
H< 
3698 
6 
3693 
3690 
4 
3680 
3677-5 
6 
3674 
6 
3667 
G 
36581 
3656 
3653 / 
3654 
3635 
Ca (?) 
3637-5 
The line 3859 was entered as a band, terminating sharply at 3865 and 3853 ; 
similarly the two lines 3658, 3653 appear on our photograph as joined together. The 
line 3955, which appears between H’ and K, is very likely the representative of a 
calcium triplet, photographed by Professors Liveing and Dewar, and having, 
according to them, a wave-length of 3972’3, 3956’0, 3947’9. The most refrangible of 
the lines appearing in the prominence seems also likely to be due to calcium ; for 
there is a calcium triplet marked as very strong, diffuse at 3644, 3631, 3623 - 5. We 
are obliged to Professors Liveing and Dewar for their information respecting these 
lines. 
The line spectrum of the corona. 
It has been mentioned that close to the sun’s limb a strong continuous spectrum 
hides any lines which might be present in these regions. We have reason to believe 
