Bright Objects near the Sun.—Small, rapidly moving bodies have been occasionally reported as seen passing over the Sun. In several cases these have been prematurely assigned a meteoric origin. They have been described as luminous bodies of irregular shape, as moving in a common direction, and as being very distinct when projected on the dark sky just outlying the bright limb of the Sun. There is little doubt they are either the pappus of different kinds of seed, or convolutions of gossamer, which have been lifted to great heights in the air, and are rendered bright by reflection from the bordering Sun. In this connection I may mention some observations of my own with a 4-inch refractor:—
“1889, May 20, 0h 30m P.M.—Bright points and little misty forms kept passing from the Sun’s limb, at the average rate of 13 in a minute. They moved in the same direction as the clouds and wind. Some of them were followed by tails, which were far from straight. I saw them best when I focused the telescope for an object much nearer than the Sun. One of these forms would occasionally halt and pursue an irregular flight. It was evident they were terrestrial objects, with motions controlled by the wind.
“3h P.M.—Many bright objects still passing from the Sun’s limb.”
“1889, May 22, 9h A.M.—Observed vast numbers of luminous particles floating about contiguous to the Sun’s margin. They were clearly carried along by the wind; but this being very slight, their motions were extremely slow, and now and then many of them became nearly stationary. Their directions were far from uniform, though the general tendency was obviously in a common line of flight. I watched them for some time passing in a plentiful shower.”
These objects are always noticed in summer-time, and I believe they would much more frequently attract remark but for the fact that they require a longer focus than the Sun and cannot be recognized when on the disk, to which the observer is usually giving the whole of his attention. Those who are often employed in solar work will find it an interesting diversion to look for these bodies. The instrument should be focused as for a distant terrestrial object, and only a part of the Sun’s limb should be retained in the field of view of an eyepiece of moderately low power. Then, looking intently at the dark sky near the limb, the bright objects will be sometimes seen sailing past in considerable numbers.
Cyclonic Action.—The appearance in detail of certain spots, coupled with evidences of rotatory motion round their own centres, has induced the belief that they are liable to action in some degree similar to the cyclonic storms[13] which disturb and rend the terrestrial atmosphere. Such indications should be looked for in fairly conspicuous spots, and any peculiarities of the nature alluded to made the subject of close investigation. A spot showing features having a spiral tendency may not, however, have a gyratory movement about its centre. This can only be determined by critically noting the details, and frequently reobserving them for traces of motion. The penumbra always shows radiations converging on the umbra as a centre; but this is merely a form of structure, and proves nothing in evidence of a revolving storm.
Sudden Outbursts of Faculæ.—In September 1859 Carrington and Hodgson independently observed a striking outburst of faculæ in front of a large group of spots which they were examining. It remained visible about five minutes, during which interval several patches of light travelled over a region nearly 34,000 miles in extent. An extraordinary magnetic disturbance was simultaneously recorded at the Kew Observatory, and sixteen hours afterwards there followed a magnetic storm of unusual severity. On another occasion Dr. Peters observed flashes of light cross and recross the umbra of a prominent spot with electric velocity. Some other startling observations of solar phenomena have been effected, and there is no question as to their having been matters of fact. In the presence of effects so sudden, so obvious, and so unexpected, no wonder the observers at first doubted the evidence of their eyes and suspected the cause to lie in a fractured glass or a fault of adjustment. But the corroboration afforded the clearest proof as to the actuality of the events described. They will doubtless occur again; but these phenomena cannot be definitely predicted as to time, so that students of the solar surface should be prepared for a repetition of them whenever they may occur.
Shadows cast by Faculæ.—M. Trouvelot, while examining a large sun-spot on May 26, 1878, noticed that it was “completely surrounded by very brilliant and massive faculæ.” “On one part of the penumbra an extraordinary appearance was perceived, which resembled so closely a shadow, as it would have been cast by the overhanging faculous mass, that it seemed useless to seek, and it was impossible to admit, any other explanation. This shadow, the outline of which was a little diffused, had the same shape as, and reproduced with great exactness, the outline of the faculous mass situated above it. It was not so black as the opening in spots called the umbra, but of a very dark tint.” A similar feature was seen by Kirk and Maclean on May 2, 1884, and the ‘Observatory,’ vol. vii. pp. 146, 170, and 197, contains some interesting particulars on this subject. Fig. 24 is a drawing by Kirk, in which the shadow is represented by A, B; at C “it accurately followed the outline of the intensely white margin of the spot.”