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examining with the telespectroscope an enormous protuberance or hydrogen closed on the eastern limb

of the Sun.

'It had remained with very little change since the preceding noon-a long, low, quiet-looking cloud, not very dense or brilliant, nor in any way remarkable except for its size. It was made up mostly of filaments nearly horizontal, and floated above the chromatosphere with its lower surface at a height of some 15,000 miles, but was connected with it, as is usually the case, by three or four vertical columns brighter and more active than the rest. Lockyer compares such masses to a banyan grove. In length it measured 3′ 45′′, and in elevation about 2' to its upper surface-that is, since at the Sun's distance 1" equals 450 miles nearly, it was about 100,000 miles long by 54,000 high.

'At 12.30, when I was called away for a few minutes, there was no indication of what was about to happen, except that one of the connecting stems at the southern extremity of the cloud had grown considerably brighter, and was curiously bent to one side; and near the base of another at the northern end a little brilliant lump had developed itself, shaped much like a summer thunder-head. Fig. 80 represents the prominence at this time, a being the little "thunder-head." ↑

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What was my surprise, then, on returning in less

This is the name given by Schellen to the combination of astronomical telescope and spectroscope.

The sketches do not pretend to accuracy of detail, except the fourth; the three rolls in that are nearly exact.

than half an hour (at 12.55), to find that in the meantime the whole thing had been literally blown to shreds by some inconceivable up-rush from beneath. In place

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of the quiet cloud I had left, the air, if I may use the expression, was filled with flying débris-a mass of detached vertical fusiform filaments, each from 10" to 30" long, by 2" or 3" wide, brighter and closer together where the pillars had formerly stood, and rapidly ascending.

This

"When I first looked some of them had already reached a height of nearly 4'(100,000 miles), and while I watched them they rose with a motion almost perceptible to the eye, until in ten minutes (1.5) the uppermost were more than 200,000 miles above the solar surface. was ascertained by careful measurement; the mean of three closely-accordant determinations gave 7′ 49′′ as the extreme altitude attained, and I am particular in the statement because, so far as I know, chromatospheric matter (red hydrogen in this case) has never

before been observed at an altitude exceeding 5. The velocity of ascent also, 166 miles per second, is considerably greater than anything hitherto recorded. A general idea of its appearance when the filaments attained their greatest elevation may be obtained from fig. 81.

As the filaments rose they gradually faded away like a dissolving cloud, and at 1.15 only a few filmy

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wisps, with some brighter streamers low down near the chromatosphere, remained to mark the place.

But in the meanwhile the little "thunder-head before alluded to had grown and developed wonderfully

into a mass of rolling and ever-changing flame, to speak according to appearances. First it was crowded down, as it were, along the solar surface; later it rose

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almost pyramidally 50,000 miles in height; then its summit was drawn out into long filaments and threads which were most curiously rolled backwards and down

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wards, like the volutes of an Ionic capital; and finally it faded away, and by 2.30 had vanished like the other. Figs. 82 and 83 show it in its full development; the former having been sketched at 1.40, and the latter 1.55.

Y

The whole phenomenon suggested most forcibly the idea of an explosion under the great prominence, acting mainly upwards, but also in all directions outwards, and then after an interval followed by a corresponding in-rush; and it seems far from impossible that the mysterious coronal streamers, if they turn out to be truly solar, as now seems likely, may find their origin and explanation in such events.

The same afternoon a portion of the chromatosphere on the opposite (western) limb of the Sun was for several hours in a state of unusual brilliance and excitement, and showed in the spectrum more than 120 bright lines whose position was determined and catalogued,—all that I had ever seen before, and some 15 or 20 besides.'*

It remains only to mention that Professor Young, of America, has succeeded in obtaining a photograph of a prominence when the Sun has been shining in full splendour. Although the result is, he tells us, not remarkable as a presentation of a solar prominence, yet as indicating the possibility of applying photography to record the condition of the chromatosphere and prominences from day to day, from month to month,

* Boston Journal of Chemistry.-Prof. Young has published a list of 103 of these chromatospheric bright lines, whereof 5 have been detected by Rayet, 16 by Lockyer, 3 by Lockyer and Janssen, 5 by Lockyer and Rayet, and the remaining 74 (besides the 17 above referred to) by Young. The elements whose existence has been recognised in the chromatosphere, are hydrogen, iron, sodium, magnesium, barium, calcium, chromium (?), nickel, and titanium, the presence of the last being a discovery of Prof. Young's.

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