Still, in admitting the possibility of some such contributory effect on the part of the moon, we must not, of course, be understood as meaning that the corona as a whole does not have a real existence, quite independent of the changes which the presence of the moon may bring; and in leaving the wonderful thing we must remember that it is, after all, a reality, and not a phantasm. [Illustration: FIG. 43.--TACCHINI’S CHROMOSPHERIC CLOUDS. (“MEMORIE DEGLI SPETTROSCOPISTI ITALIANI.”)] [Illustration: FIG. 44.--TACCHINI’S CHROMOSPHERIC CLOUDS. (“MEMORIE DEGLI SPETTROSCOPISTI ITALIANI.”)] I have already described how, at the eclipse of 1870, I (with others) saw within the corona what seemed like rose and scarlet-colored mountains rising from the sun’s edge, an appearance which had first been particularly studied in the eclipse of 1868, two years before, and which, it might be added, Messrs. Lockyer and Janssen had succeeded in observing without an eclipse by the spectroscope. Besides the corona, it may be said, then, that the sun is surrounded by a thin envelope, rising here and there into prominences of a rose and scarlet color, invisible in the telescope, except at a total eclipse, but always visible through the spectroscope. It is within and quite distinct from the corona, and is usually called the “chromosphere,” being a sort of sphere of colored fire surrounding the sun, but which we can usually see only on the edge. “The appearance,” says Young, “is as if countless jets of heated gas were issuing through vents and spiracles over the whole surface, thus clothing it with flame, which heaves and tosses like the blaze of a conflagration.” Out of this, then, somewhat like greater waves or larger swellings of the colored fires, rise the prominences, whose place, close to the sun’s edge, has been indicated in many of the drawings and photographs just given of the corona, on whose background they are seen during eclipses; but as they can be studied at our leisure with the spectroscope, we have reserved a more particular description of them till now. They are at all times directly before us, as well as the corona; but while both are yet invisible from the overpowering brightness of the sunlight reflected from the earth’s atmosphere in front of them, these red flames are so far brighter than the coronal background, that if we could only weaken this “glare” a little, they at least might become visible, even if the corona were not. The difficulty is evidently to find some contrivance which will weaken the “glare” without enfeebling the prominences too; and this the spectroscope does by diffusing the white sunlight, while it lets the color pass nearly unimpaired. For the full understanding of its action the reader must be referred to such works as those on the sun already mentioned; but a general idea of it may be gathered, if we reflect that white light is composed of every possible variety of colors, and