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Trying with the help of these still inadequate images, we may get some idea of the real size and distance of the sun. I could wish not to have to dwell upon such figures, that seem, however, indispensable; but we are now done with these, and are ready to turn to the telescope and see what the sun itself looks like.

FIG. 2.—VIEW OF THE SUN ON SEPT. 20, 1870.

FIG. 3.—THE SUN ON SEPT. 22, 1870.

(FROM A PHOTOGRAPH)

The sun, as we shall learn later, is a star, and not a particularly large star. It is, as has been said, “only a private in the host of heaven,” but it is one of that host; it is one of those glittering points to which we have been brought near. Let us keep in mind, then, from the first, what we shall see confirmed later, that there is an essentially similar constitution in them all, and not forget that when we study the sun, as we now begin to do, we are studying the stars also.

If we were called on to give a description of the earth and all that is on it, it would be easily understood that the task was impossibly great, and that even an account of its most striking general features might fill volumes. So it is with the sun; and we shall find that in the description of the general character of its immediate surface alone, there is a great deal to be told. First, let us look at a little conventional representation (Fig.1), as at a kind of outline of the unknown regions we are about to explore. The circle represents the Photosphere, which is simply what the word implies, that “sphere” of “light” which we have daily before our eyes, or which we can study with the telescope. Outside this there is a thin envelope, which rises here and there into irregular prominences, some orange-scarlet, some rose-pink. This is the Chromosphere, a thin shell, mainly of crimson and scarlet tints, invisible even to the telescope except at the time of a total eclipse, when alone its true colors are discernible, but seen as to its form at all times by the spectroscope. It is always there, not hidden in any way, and yet not seen, only because it is overpowered by the intenser brilliancy of the Photosphere, as a glow-worm’s shine would be if it were put beside an electric light. Outside all is the strange shape, which represents the mysterious Corona, seen by the naked eye in a total eclipse, but at all other times invisible even to telescope and spectroscope, and of whose true nature we are nearly ignorant from lack of opportunity to study it.