Page:Popular Science Monthly Volume 60.djvu/255

Rh 135,000 miles to 281,000 miles. This implies a velocity of at least 100 miles per second.

At times of total eclipse it is perhaps possible to obtain better photographs showing finer details than can be made under other conditions. Figure 5 is an enlargement of a photograph made at the eclipse of 1900, by Professor E. E. Barnard, assisted by Mr. G. W. Ritchey. It shows a mass of prominences at the southwest quadrant of the sun. Along the irregular limb of the moon, which appears black, is seen the ragged storm-tossed surface of the chromosphere, of increasing depth toward the right owing to the moon's position at the instant of the exposure. Thrown up from this are the vast fantastic masses of the prominences or 'red flames.' They remind us of pictures which show the effects produced by the explosion of submarine torpedoes. The larger mass at the left rises to the height of 60,000

miles. This photograph was made with a telescope of only six inches aperture and six and a half feet focal length, a small instrument compared with some which have been used at recent eclipses. The writer has seen no other photograph of prominences, however, which, in delicacy of detail, surpasses the one here shown.

The single feature of a total eclipse which can be seen and studied only at such times is the corona. In early ages small mention was made of the corona. Apparently the dread of impending evil overwhelmed man, and prevented careful observations. As fear disappeared and scientific interest grew, attention was drawn to the 'red flames,' and at nearly the same time to the beautiful halo of light which has been fittingly named the 'corona.' Since that time the favorable moments of totality have been too few to clear up the mystery of its nature. Reasoning from the methods which have made the study of the chromosphere and prominences possible without an eclipse, various attempts have been also made to thus observe and photograph the corona. The simplest way would be by direct vision or photography. There is no doubt but that, if we could remove for a moment the earth's atmosphere, whose glare interferes with our vision, we