426 MR. J. N. LOCKYER ON SPECTROSCOPIC OBSERVATIONS OF THE SUN. 
1 began my work with the new instrument by continuing my search after the pro- 
minences. I found that the circumsolar light was now so greatly reduced that, although 
the lines were faintly seen on a dimly coloured background, the background itself was 
apparently dark enough to render a bright line distinctly visible. My first attempts, 
however, with the new instrument, not yet in adjustment, were as unsuccessful as those 
made with the smaller one ; and it was not till the 20th of October that, after sweeping 
for about an hour round the limb and arriving at the vertex of the image, near the 
south pole of the sun, I saw a bright line flash into the field. 
My eye was so fatigued at the time that I at first doubted its evidence, although, 
unconsciously, I exclaimed “ at last ! ” The line, however, remained — an exquisitely 
coloured line absolutely coincident with the line C of the solar spectrum, and, as I saw 
it, a prolongation of that line. Leaving the telescope to be driven by the clock, I quitted 
the observatory to fetch my wife to endorse my observation. 
Detail of the Observations. 
October 20. — Having settled that the new line was absolutely coincident with C, I 
commenced to search for more lines. This I found very difficult, as the instrument 
requires several movements and adjustments for the various parts of the spectrum, and 
the rate of the driving-clock was not properly adjusted for the sun’s motion; the pra- 
minence was therefore lost at times ; moreover the observations were impeded by clouds. 
I commenced the search for lines from C to A. B was first brought into the field 
with the newly discovered line at C. There were no new lines visible. I then made an 
excursion to A with no result, and returned to C to assure myself that the prominence 
was still on the slit. 
I then worked from the line at C towards D. A little beyond D, the lines of which 
are widely separated in my instrument, I detected another single and less vivid line, by 
estimation 8° or 9° of Kirchhoff’s scale more refrangible than the more refrangible of 
the strongest D lines. I could detect no line corresponding to it in the solar spectrum, 
but the definition was not good. 
b was next tried, the excursion now being made from the new line near D. There 
was no line at 5, though the new D line was still visible when I returned to it. 
In the same manner, after many interruptions from clouds, I tried F ; here I found 
aujourd’hui) me parait tenir a ce que ce savant, dans 1’impossibilite ou il etait alors de prevoir de quelles raies 
lumineuses se composerait le spectre des protuberances supposees gazeuses, ne savait sur quelles particularites 
delicates du spectre si complique des regions circumsolaires il devait porter son attention. Gela est si vrai, que 
c’est seulement quancl il a su, par les observateurs franpais et anglais de V eclipse, la nature detaillee du spectre des 
protuberances, qu’il a reussi a tronver en Angleterre les traces de ce spectre dans celui des regions voisines du 
bord du soleil.” 
I think that the illustrious French astronomer, who has otherwise done me such ample justice, will not object 
to my pointing out this slight inaccuracy, due entirely to the fact that the first communication of my discovery 
was incomplete in its statement of the circumstances which attended it. The bright lines as seen in my instru- 
ment are so obvious and brilliant that a child could not overlook them. — J. N. L., October 10, 1869. 
