revelation. To cover the sun's disk with a circular screen will not
answer the purpose because of the illumination of the air all about
the observer. When the moon hides the sun, on the other hand, the
sunlight is withdrawn from a great cylinder of air extending to the
top of the atmosphere and spreading many miles around the observer.
There is then no glare to interfere with the spectacle, and the corona
appears in all its surprising beauty. The prominences, however,
although they were discovered during an eclipse, can now, with the aid
of the spectroscope, be seen at any time. But the prominences are
rarely large enough to be noticed by the naked eye, while the
streamers of the corona, stretching far away in space, like ghostly
banners blown out from the black circle of the obscuring moon, attract
every eye, and to this weird apparition much of the fear inspired by
eclipses has been due. But if the corona has been a cause of terror in
the past it has become a source of growing knowledge in our time.

The story of the first scientific observation of the corona and the
prominences is thrillingly interesting, and in fact dramatic. The
observation was made during the eclipse of 1842, which fortunately was
visible all over Central and Southern Europe so that scores of
astronomers saw it. The interest centers in what happened at Pavia in
Northern Italy, where the English astronomer Francis Baily had set up
his telescope. The eclipse had begun and Bailey was busy at his
telescope when, to quote his own words in the account which he wrote
for the Memoirs of the Royal Astronomical Society:

I was astounded by a tremendous burst of applause from the streets
below, and at the same moment was electrified by the sight of one
of the most brilliant and splendid phenomena that can well be
imagined; for at that instant the dark body of the moon was