Majestic, indeed, are the proportions of some of those mighty flames which leap from the surface of the sun, yet these flames flicker, as do our terrestrial flames, when we allow them time comparable to their gigantic dimensions. Drawings of the same prominence often show great changes in a few hours, or even less. The magnitude of the changes could not be less than many thousands of miles, and the actual velocity with which such masses move is often not less than one hundred miles a second. Still more violent are the solar convulsions, which some observers have been so fortunate as to behold, when from the sun’s surface, as from a mighty furnace, vast incandescent masses are projected upwards. All indications point to the surface of the sun as the seat of the most frightful storms and tempests, in which the winds sweep along incandescent vapors. The corona consists of two parts--the inner and brighter corona, the outer and fainter corona. The shape of the whole seems to change much at different times. The outer edge is usually blurred and indistinct, fading gently away. Many explanations have been suggested. At one time the corona was supposed to be a solar atmosphere, reflecting light like our own atmosphere. Some have thought the light might be caused by countless myriads of meteorite systems, revolving in the close neighborhood of the sun. Some suppose it may be owing, in part at least, to solar eruptions, and the pouring outward of burning gas and matter. But our knowledge of the true nature of the corona is yet in its infancy. A few closing words as to the size and weight of the sun. In diameter, eight hundred and fifty-eight thousand miles, and in bulk equal to one million two hundred and eighty thousand earths, his weight is in proportion less. Our earth is about four times as dense as the sun. If her size were increased to the sun’s size, her density being the same as now, she would be very much heavier than the sun, and would attract much more strongly. Still, though the sun is of lighter materials than the earth, his immense size gives him weight equal to seven hundred and fifty times as much as all the planets put together.