as first brought fully home to
astronomers by the eclipse of 1842. The brilliant and complex appearance
which on that occasion challenged the attention of so many observers,
demanded and received, no longer the casual attention hitherto bestowed
upon it, but the most earnest study of those interested in the progress
of science. Nevertheless, it was only by degrees, and through a process
of "exclusions" (to use a Baconian phrase) that the corona was put in
its right place as a solar appendage. As every other available
explanation proved inadmissible and dropped out of sight, the broad
presentation of fact remained, which, though of sufficiently obvious
interpretation, was long and persistently misconstrued. Nor was it until
1869 that absolutely decisive evidence on the subject was forthcoming,
as we shall see further on.

Sir John Herschel, writing to his venerable aunt, relates that when the
brilliant red flames burst into view behind the dark moon on the morning
of the 8th of July, 1842, the populace of Milan, with the usual
inconsequence of a crowd, raised the shout, "_Es leben die
Astronomen!_"[175] In reality, none were less prepared for their
apparition than the class to whom the applause due to the magnificent
spectacle was thus adjudged. And in some measure through their own
fault, for many partial hints and some distinct statements from earlier
observers had given unheeded notice that some such phenomenon might be
expected to attend a solar eclipse.

What we now call the "chromosphere" is an envelope of glowing gases, by
which the sun is completely covered, and from which the "prominences"
are emanations, eruptive or flame-like. Now, continual indications of
the presence of this fire-ocean had been detected during eclipses in the
eighteenth and nineteenth centuries. Captain Stannyan, describing in a
letter to Flamsteed an occurrence of the kind witnessed by him at Berne
on May 1 (o.s.), 1706, says that the sun's "getting out of the eclipse
was preceded by a blood-red streak of light from its left limb."[176] A
precisely similar appearance was noted by both Halley and De Louville in
1715; during annular eclipses by Lord Aberdour in 1737,[177] and by
Short in 1748,[178] the tint of the ruby border being, however, subdued
to "brown" or "dusky red" by the surviving sunlight; while observations
identical in character were made at Amsterdam in 1820,[179] at Edinburgh
by Henderson in 1836, and at New York in 1838.[180