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 eclipse when the black disc of the moon passed in front of the glaring face of the sun leaving only the red flames licking out beyond the dark edge. The invention of the spectroheliograph now makes it possible to photograph these projections when the sun is shining. One should never try to see them by looking at the sun unless the glare is shut off either by the moon or by artificial means, for the sun is so unbearably brilliant that the eyesight of an observer would soon be ruined.

This colorful gas which covers the surface of the sun, is called the chromosphere or color-sphere on account of the vivid color which it acquires from the hydrogen and calcium of which it is largely composed. The colossal flames which rise above its surface are called prominences. Some of the prominences shoot up with a velocity ranging from 300 to 600 miles a second, sometimes to a height of 200,000 miles, and even higher. The largest so far recorded extended upward for 500,000 miles. Others extend horizontally for a distance of over 300,000 miles, racing forward at the rate of a thousand miles a minute, although sometimes they remain in an unchanged position above the surface of the sun for days at a time. These flames seem tremendous compared to our