FIG. 18.—“THE PLUME” SPOT OF MARCH 5 AND 6, 1873. (FROM AN ORIGINAL DRAWING BY S. P. LANGLEY.)
The photograph has transported us already so near the sun’s surface that we have seen details there invisible to the naked eye. We have seen that what we have called “spots” are indeed regions whose actual vastness surpasses the vague immensity of a dream, and it will not cause surprise that in them is a temperature which also surpasses greatly that of the hottest furnace. We shall see later, in fact, that the whole surface is composed largely of metals turned into vapor in this heat, and that if we could indeed drop our great globe itself upon the sun, it would be dissipated as a snow-flake. Now, we cannot suppose this great space is fully described when we have divided it into the penumbra, umbra, and nucleus, or that the little photograph has shown us all there is, and we rather anticipate that these great spaces must be filled with curious things, if we could get near enough to see them. We cannot advantageously enlarge our photograph further; but if we could really come closer, we should have the nearer view that the work at Allegheny, I have just alluded to, now affords. The drawing ([Fig. 15]) of the central part of the same great spot, already cited, was made on the 21st of September, 1870, and may be compared with the photograph of that day. We have now a greatly more magnified view than before, but it is not blurred by the magnifying, and is full of detail. We have been brought within two hundred thousand miles of the sun, or rather less than the actual distance of the moon, and are seeing for ourselves what was a few years since thought out of the reach of any observer. See how full of intricate forms that void, black, umbral space in the photograph has become! The penumbra is filled with detail of the strangest kind, and there are two great “bridges,” as they are called, which are almost wholly invisible in the photograph. Notice the line in one of the bridges which follows its sinuosities through its whole length of twelve thousand miles, making us suspect that it is made up of smaller parts as a rope is made up of cords (as, in fact, it is); and look at the end, where the cords themselves are unravelled into threads fine as threads of silk, and these again resolved into finer fibres, till in more and more web-like fineness it passes beyond the reach of sight! I am speaking, however, here rather of the wonderful original, as I so well remember it, than of what my sketch or even the engraver’s skill can render.
FIG. 19.—TYPICAL SUN SPOT OF DECEMBER, 1873.
(REDUCED FROM AN ORIGINAL DRAWING BY S. P. LANGLEY.)
FIG. 20.—FROST CRYSTAL.
Next we have quite another “spot” belonging to another year (1873). First, there is a view ([Fig. 17]) of the sun’s disk with the spot on it (as it would appear in a small telescope), to show its relative size, and then a larger drawing of the spot itself ([Fig. 16]), on a scale of twelve thousand miles to the inch, so that the region shown to the reader’s eyes, though but a “spot” on the sun, covers an area of over one billion square miles, or more than five times the entire surface of the earth, land, and water. To help us to conceive its vastness, I have drawn in one corner the continents of North and South America on the same scale as the “spot.” Notice the evidence of solar whirlwinds and the extraordinary “plume” ([Fig. 16]), which is a something we have no terrestrial simile for. The appearance of the original would have been described most correctly by such incongruous images as “leaf-like” and “crystalline” and “flame-like;” and even in this inadequate sketch there may remain some faint suggestion of the appearance of its wonderful archetype, which was indeed that of a great flame leaping into spires and viewed through a window covered with frost crystals. Neither “frost” nor “flame” is really there, but we cannot avoid this seemingly unnatural union of images, which was fully justified by the marvellous thing itself. The reader must bear in mind that the whole of this was actually in motion, not merely turning with the sun’s rotation, but whirling and shifting within itself, and that the motion was in parts occasionally probably as high as fifty miles per second,—per second, remember, not per hour,—so that it changed under the gazer’s eyes. The hook-shaped prominence in the lower part (actually larger than the United States) broke up and disappeared in about twenty minutes, or while the writer was engaged in drawing it. The imagination is confounded in an attempt to realize to itself the true character of such a phenomenon.
FIG. 21.—CYCLONE SPOT. (DRAWN BY FATHER SECCHI.)