130 Proceedings of the Asiatie Society. [ JUNE, 
my Report on the Keclipse of 1868, the comparatively cold 
atmosphere of the Sun. This should be farther spectrosco- 
pically examined. Observers have differed about the number and 
position of the faint bright lines they have seen, but it does not 
seem that any one has connected the variations with the position 
of the part examined. ‘To do this appears urgently necessary, and 
there have been additions made to the spectroscope which will 
allow more than one portion of the Corona to be examined, and 
its lines recorded during the short time it is visible. 
There is another subject too of spectroscopic examination. Kirch- 
hoff in his theory of the solar constitution supposed it surrounded 
by an extensive atmosphere consisting of metallic and other vapours, 
as well as gases, by the absorption of which the dark Fraunhofer 
lines were produced. It has long been clear that there was no 
such extensive atmosphere and some physicists have been satisfied 
that there is none such. Mr. Lockyer and his collaborateurs, 
though they have detected a greater number of bright lines at the 
bases of the prominences, have never approached, so far as I know, 
the number of even the conspicuous dark lines, whose explanation 
has, therefore, not been satisfactorily made out. At the Kclipse of 
December 22, 1870, however, Professor Young at the moment of 
obscuration, and for one or two seconds later, saw as far as he 
could judge every atmospheric line reversed, and this was con- 
firmed by Mr. Pye. I have but the scant information of this 
point given in the Royal Astronomical Society’s Council Report, 
but it is sufficient to show me why this has not been seen before 
by observers looking out for it, and also to make me feel the im- 
portance of verifying the observation. 
To understand why it has not been seen before, it must be con- 
sidered that the image of a bright object in the focus of a Tele- 
scope when relieved against comparative darkness is enlarged by a 
phenomenon known as irradiation; the light encroaches on the 
darkness. The sun thus appears larger and the moon smaller 
than the real size. This continues till the real contact of the Limbs 
internally ; at this moment the thread of light, which previously had 
considerable width, appears suddenly broken and vanishes in a 
- Total Eclipse: while in the Transit of a Planet or Annular Kelipse 
