When first seen, coming round on one side, they are in shape, more or less, of narrow ovals, and very little of the inside can be seen. As they travel on with the spinning Sun, and get near the middle of the Sun’s face, the oval openings widen and grow round, while more of the dark depths can be seen. Then, passing to the farther edge, they again grow narrow, as at first. So we feel sure that the spots are hollows or caves, not mountains. I do not mean such hollows and caves as are found on the earth, but more like the holes that may be seen in a mass of stormy clouds. They seem to be huge rents in glowing Sun-clouds. Usually they have a black centre, with a gray border round the blackness. Now and then, as in the picture of a sun-spot given in this book, the gray part is wanting. Sun-spots are sometimes larger, sometimes smaller; but none that we see at this distance can be really small. Fifty or sixty thousand miles across is a very common size. Once in a while a spot is more than a hundred thousand miles from edge to edge. So, though we talk of _little_ black spots on the Sun’s face, they are not really little, but exceedingly big. And if we were near they would not look black, but fiery. The Moon’s craters seemed big when we first thought of them--fifty or one hundred miles across; very huge beside our tiny Earth craters. These crater-like hollows, however, in the Sun’s cloudy surface are fifty or one hundred _thousand_ miles across! The whole Moon dropped into such a hole as this would be a mere little ball in a corner. The Sun is enormously heavier than our Earth, because enormously bigger. Yet in actual _make_ the Sun is light. Instead of being all through as solid as our little Earth, he only weighs as much as if made of something not much heavier than water. We do not know whether any part of the Sun is really solid and firm. Perhaps not even the innermost parts of that vast globe, certainly not any of the outermost parts. For the heat must be so awful as to turn everything there into gases. Not cool gases, but raging fiery gases, rushing furiously to and fro. Over the whole brilliant body of the Sun is spread a mighty ocean--not of cool water, like our seas, but of crimson fiery gas-waves. And out of this ocean spring crimson mountains of fiery gas. And beyond these jagged mountains--little, as seen from the Earth, but really of great height--lies a beautiful and wide-spreading wreath of pearly light, called “The Corona,” or, “The Crown.” The bright face of the Sun and its tiny black spots can be easily seen from the Earth. But the crimson sea, showing as a red border round the edge, and the fiery mountains, and the crown of light, are very seldom to be seen. When an eclipse of the Sun happens, then for a few seconds they are clearly visible to people with telescopes. Besides the black spots and the red mountains, bright white spots are sometimes noticed.