428 ME. J. N. LOCKYEE ON SPECTEOSCOPIC OBSEEVATIONS OP THE SUN. 
new, and that possibly what I was seeing might indicate a solar envelope. I rapidly, 
therefore, tried several other parts of the limb to test the idea. It was soon established. 
In every solar latitude loth the C and F bright lines were seen extending above the solar 
spectrum. The spectrum near D was so bright that I was compelled to refrain from 
examining it, but I caught the line near D once. 
The thickness of this envelope I found to be sensibly uniform, except in the regions 
where it was heaped up with prominences. 
The spectrum of the envelope cleared up all the difficulties connected with the 
F line. Perfect definition and adjustment now enabled me to see that the base of the 
bright line widens out as the solar spectrum is approached, and that whereas the line, 
away from the sun, corresponds, in the case of an ordinary prominence, in refrangibility 
and thickness to the Feaunhofee line F, close to the sun it widens out, so as to overlap 
the F line on both its sides to an extent about equal to its thickness, so that it is three 
times broader, or perhaps more, on and close to the limb. 
In the spectrum of a prominence in which violent action was going on the line thick- 
ened out in the same manner at some distance above the limb (Plate XXXVII. fig. 4). 
There was no thickening observed in the C line at the base, or in the case of the pheno- 
menon just referred to. 
I obtained on this day the outlines and dimensions of two prominences. 
November 6. — The observations made on the preceding day were confirmed, and one 
of the prominences reobserved. I also suspected a new line a little less refrangible 
than C. 
November 8. — The line suspected on the 6th was seen several times to-day. It came 
out beautifully with very varying brilliancy and even colour, to judge by appearance and 
impressions. It is very much thinner than the bright line C, and seems only to flash 
out where great action is going on, which slightly thickens the C line at its base. It is 
so near the C line that when both are shining brilliantly the line looks a double one, 
like D in a spectroscope of moderate dispersive power. 
To-day for the first time I got definite evidence of what I had suspected on several 
occasions with regard to different parts of the spectrum. A bright line was observed in 
the solar spectrum itself, a little less refrangible than the line C. 
On the Spectrum of the Prominences. 
The existence of three lines in the spectrum of the prominences and their approximate 
positions were determined and communicated to the Royal Society on the 20th of 
October. See Plate XXXVII. figs. 1, 2, 3. 
The coincidence of one of the lines with the solar line C was at once determined. 
The coincidence of another line with F at a certain distance from the sun’s surface was 
finally determined on the 5th of November, when the fact of the widening out of the 
lines towards the sun was discovered. 
The exact position of the line near D is shown in Plate XXXVII. fig. 2, in which it 
