Page:Popular Science Monthly Volume 5.djvu/558

540 fast, while the other is left free. This is so very generally the case that we see that, if these filaments be clouds, they differ from ours in other circumstances than their shape. Those we are studying are bent into curves, which show that the solar winds frequently move in circular sweeps, and are, to a considerable degree, comparable with our cyclones. Long, twisted ropes are sometimes formed by them, one being thrown over another; and, in cloud-like masses, they at times move over and conceal lower portions of the penumbra—the abrupt changes in the directions of motion showing us that these are superposed strata of what, for want of a better word, we must call solar clouds, which drift across each other's course occasionally, nearly at right angles, while the ever-moving whirlwinds leave an unmistakable record of their action on these pliant forms.

In one part of the spot, one of these has been bent into a complete loop, or closed curve, the extremity showing a fringe of ragged strands, like that of a broken rope. The immensely more extended scale of the action here being kept in view, and the fact that the whole spot is being changed in all its parts—even while we are looking at it—by alterations which, though apparently gradual, are really the indications of an immense energy, it will be seen that, considered merely as a spectacle of the play of natural forces, we have before us something almost incomparably greater than any which the terrestrial volcano, earthquake, or cyclone, can offer. The entire surface of the earth, were it spread out into a plain, would be, in fact, of inconsiderable size as compared with either branch of the spot we are examining.

The quickness of the transformations that the observer sometimes notes here is wonderful. Lockyer, Young, and other observers, have demonstrated the existence of chromospheric movements, in some instances, at the rate of over 100 miles a second; and the velocities in the photosphere are, occasionally, of a similar order of magnitude. As an instance, it may be mentioned that the loop in question, which inclosed an area of about 3,000,000 square miles (not far from that of the United States), broke up, and seemingly melted away, like a snow-wreath before a fire, in little over a quarter of an hour. How vain the attempt must be to adequately realize to ourselves the features of such a cataclysm seen close at hand!

It is quite impracticable to convey an adequate idea of the complexity, strangeness, and beauty of these penumbral forms by an engraving; and the description is likely to fail equally, both on account of the unlikeness of the appearances to any thing with which we are familiar, and the difficulty of using any descriptive terms which, drawn from terrestrial analogies, will not here prove inaccurate. A plume-like form, in the upper portion of the spot, is necessarily but an imperfect memorandum of an appearance, in reality all but impossible to render with the pencil, even on a scale which depicted it a hundred times this size. It might be likened to a sheet of glass, covered with