as ever since
been known by the name of "Baily's beads." Spurred by his observation,
the leading astronomers of the day determined to pay particular
attention to a total eclipse, which in the year 1842 was to be visible
in the south of France and the north of Italy. The public interest
aroused on this occasion was also very great, for the region across
which the track of totality was to pass was very populous, and inhabited
by races of a high degree of culture.

This eclipse occurred on the morning of the 8th July, and from it may be
dated that great enthusiasm with which total eclipses of the sun have
ever since been received. Airy, our then Astronomer Royal, observed it
from Turin; Arago, the celebrated director of the Paris Observatory,
from Perpignan in the south of France; Francis Baily from Pavia; and Sir
John Herschel from Milan. The corona and three large red prominences
were not only well observed by the astronomers, but drew tremendous
applause from the watching multitudes.

The success of the observations made during this eclipse prompted
astronomers to pay similar attention to that of July 28, 1851, the total
phase of which was to be visible in the south of Norway and Sweden, and
across the east of Prussia. This eclipse was also a success, and it was
now ascertained that the red prominences belonged to the sun and not to
the moon; for the lunar disc, as it moved onward, was seen to cover and
to uncover them in turn. It was also noted that these prominences were
merely uprushes from a layer of glowing gaseous matter, which was seen
closely to envelop the sun.

The total eclipse of July 18, 1860, was observed in Spain, and
photography was for the first time _systematically_ employed in its
observation.[7] In the photographs taken the stationary appearance of
both the corona and prominences with respect to the moving moon,
definitely confirmed the view already put forward that they were actual
appendages of the sun.

The eclipse of August 18, 1868, the total phase of which lasted nearly
six minutes, was visible in India, and drew thither a large concourse of
astronomers. In this eclipse the spectroscope came to the front, and
showed that both the prominences, and the chromospheric layer from which
they rise, are composed of glowing vapours--chief among which is the
vapour of hydrogen. The direct result of the observations made on this
occasion was the spectroscopic method of examining prominences at any
ti