become so much reduced, and the shell so much thickened,
that the escape of the heat generated is greatly retarded.... M. Faye's
hypothesis appears to be espoused by him, partly because it affords an
explanation of the spots, which are considered as openings in the
photosphere, exposing the comparatively non-luminous gases filling the
interior. But if these interior gases are non-luminous from the absence
of precipitated matter, must they not for the same reason be
transparent? And if transparent, will not the light from the remote side
of the photosphere seen through them, be nearly as bright as that of the
side next to us? By as much as the intensely-heated gases of the
interior are disabled by the dissociation of their molecules from giving
off luminiferous undulations, by so much must they be disabled from
absorbing the light transmitted through them. And if their great
light-transmitting power is exactly complementary to their small
light-emitting power, there seems no reason why the interior of the Sun,
disclosed to us by openings in the photosphere, should not appear as
bright as its exterior.

Take, on the other hand, the supposition that a more advanced state of
concentration has been reached. A shell of molten metallic matter
enclosing a gaseous nucleus still higher in temperature than itself,
will be continually kept at the highest temperature consistent with its
state of liquid aggregation. Unless we assume that simple radiation
suffices to give off all the heat generated by progressing integration,
we must conclude that the mass will be raised to that temperature at
which part of its heat is absorbed in vaporizing its superficial parts.
The atmosphere of metallic gases hence resulting, cannot continue to
accumulate without reaching a height above the Sun's surface, at which
the cooling due to radiation and rarefaction will cause condensation
into cloud--cannot, indeed, cease accumulating until the precipitation
from the upper limit of the atmosphere balances the evaporation from its
lower limit. This upper limit of the atmosphere of metallic gases,
whence precipitation is perpetually taking place, will form the visible
photosphere--partly giving off light of its own, partly letting through
the more brilliant light of the incandescent mass below. This conclusion
harmonizes with the appearances. Sir John Herschel, advocating though he
does an antagonist hypothesis, gives a description of the Sun's surface
whi