s, was renewed in that of 1874. The phenomenon is
largely an effect of what is called _irradiation_, by which a bright
object seems to encroach upon a dark one; but under good atmospheric and
instrumental conditions it becomes inconspicuous. The "Beads" must
always appear when the projected lunar edge is serrated with mountains.
In Baily's observation, they were exaggerated and distorted by an
irradiative _clinging together_ of the limbs of sun and moon.

The immediate result, however, was powerfully to stimulate attention to
solar eclipses in their _physical_ aspect. Never before had an
occurrence of the kind been expected so eagerly or prepared for so
actively as that which was total over Central and Southern Europe on the
8th of July, 1842. Astronomers hastened from all quarters to the
favoured region. The Astronomer Royal (Airy) repaired to Turin; Baily to
Pavia; Otto Struve threw aside his work amidst the stars at Pulkowa, and
went south as far as Lipeszk; Schumacher travelled from Altona to
Vienna; Arago from Paris to Perpignan. Nor did their trouble go
unrewarded. The expectations of the most sanguine were outdone by the
wonders disclosed.

Baily (to whose narrative we again have recourse) had set up his
Dollond's achromatic in an upper room of the University of Pavia, and
was eagerly engaged in noting a partial repetition of the singular
appearances seen by him in 1836, when he was "astounded by a tremendous
burst of applause from the streets below, and at the same moment was
electrified at 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 suddenly surrounded with a corona, or kind of bright
glory similar in shape and relative magnitude to that which painters
draw round the heads of saints, and which by the French is designated an
_aureole_. Pavia contains many thousand inhabitants, the major part of
whom were, at this early hour, walking about the streets and squares or
looking out of windows, in order to witness this long-talked-of
phenomenon; and when the total obscuration took place, which was
_instantaneous_, there was a universal shout from every observer, which
'made the welkin ring,' and, for the moment, withdrew my attention from
the object with which I was immediately occupied. I had indeed
anticipated the appearance of a luminous circle round the moon during
the time of total obscurity; but I did not expect, from