TRANSLATIONS AND SELECTED ARTICLES, 301. 
The, sun might be a dark body, surrounded by an atmosphere at 
some; distance, which is comparable with the atmosphere of the earthy. 
as being the seat of a continuous layer of opake and reflective clouds. 
To this first atmosphere might succeed a second, self-luminous, which 
has-been called the photosphere, and this, distant more or less from the 
interior cloudy atmosphere, would determine by its outline the visible 
limits of the star. Pursuing this hypothesis, spots. would be formed 
on the sun, as often as there occurred, in these two concentric atmos- 
pheres, corresponding openings (eclaircies) which permitted a view of 
the dark central body. Persons who have studied the phenomena 
with powerful telescopes—astronomers by profession, and competent 
judges—recognize in the hypothesis of the sun’s physical constitution, 
which I am going to speak of, a satisfactory account of the observed 
facts, yet. it is not generally adopted.* Some writers of authority: 
would represent the spots to be merely scorie floating on the liquid 
surface of the star, and given out by the solar volcanoes, of which 
we have only a feeble image in those of our earth. It was desirable, 
therefore, that we should proceed, by direct observations, to deter- 
mine the nature of the sun’s incandescent matter. But when we 
reflect that we are distant from this star by an interval of thirty-eight 
millions of leagues, and that we can only communicate with his 
visible surface by means of the luminous rays which proceed from it, 
to propose this problem to ourselves seemed to be unjustifiable rash- 
ness. The recent progress in the science of Optics has, however, fur- 
nished the means of completely solving it, and certain details, which 
you will pardon my laying before you, will render this solution evident. 
Everybody at the present day is aware that physicists have been led to 
distinguish two tinds of light—natural and polarized. A ray of the 
first species possesses properties which are the same for each point of 
its contour ; but it is not so for polarized light, where different sides 
of the rays have not the same properties. These differences are shewn 
in numerous phenomena which I need not here mention. Before 
going further, let us remark that there is something strange in the 
results which have logically led physicists to speak of different sides 
of aray of light, thus drawing a distinction between one side and 
* At the present day this: hypothesis finds even still less favor. Weshall see presently » 
that the argument for the existence of this dark central body is inconclusive, and is opposed. 
to. more recent experiments. All the phenomena connected with the spots can be satisface 
torily explained on the supposition that they are.cloudy masses floating in the sun’s atmo. 
sphere; of the reality of which clouds the subsequent remarks of the author leave no doubt. , 
—(Trans.). 
