308 TRANSLATIONS AND SELECTED ARTICLES. 
of 1851, puta stop without possibility of recurrence to those 
explanations of the protuberances which are founded on the suppo- 
sition that there existed in the sun mountains whose summits 
extended considerably beyond the photosphere. 
W ben it shall be rigorously proved that these luminous phenomena 
cannot be the effect of the inflexions which the sun’s rays undergo in 
passing near the inequalities which border the moon’s contour ; when 
it shall be proved that these rosy tints cannot be assimilated with 
mere optical appearances—that they have a real existence, and are 
veritable solar clouds :—then we shall have a new atmosphere to add 
to the two of which we have cael spoken, for clouds could not 
sustain themselves in a vacuum.* 
Everyone now knows what the uncertainty is which remains as to 
a very special point in the sun’s physical constitution. When we 
reflect that the phenomena which might serve to resolve all our 
doubts are habitually invisible and that they can only be seen during 
total eclipses of the sun—that such total eclipses are few in number— 
that, since the invention of the telescope, the astronomers of Europe 
and America have hardly had the 6pportunity of making proper obser- 
vations on more than six occasions—no one will have a right to be 
astonished that, in the middle of the 19th century, the question 
raised by these mysterious red flames, of which we have spoken so 
much, is yet a subject of study. 
After these examinations, of which you will pardon the length, let 
* In order that these clouds might sustain themselves in a vacuum, it would be necessary 
that the centrifugal force arising from their circular motion should be at each instant equal 
to the gravitation which would tend to make them fall to the sun. It would be necessary to 
transform them into actual planets revolving about this body with an extreme rapidity. 
Such is, in substance, the explanation which M. Babinet has given of the protuberances of 
1842, at the meeting of the Academy of Sciences, on 16 February, 1846. The reader will see, 
in the memoir of the learned academician, the ingenious considerations on which this theory 
reposes, and how it may be connected with the cosmogonic system of Laplace. I believe, 
now that the phenomenon has been minutely observed, that M. Babinet will find more than 
one difficulty in reconciling the immense velocity which he is forced to assign to the matter 
of those protuberances, with the relative immobility of those which were observed in 1851, 
and the change of height which they presented. These difficulties disappear when the 
spots are assimilated to clouds, floating in a solar atmosphere which has a rotatory motion 
of small rapidity. I would besides remark that the existence of this third atmosphere is 
established by phenomena of an altogether different kind, namely, by the comparative 
intensities of the rim and centre of the sun, and also, in some respects, by the zodiacal light 
which is so visible in our climates at the time of the equinoxes. But the question considered 
in this point of view would require details that I am forced to omit.—(Awthor’s note.) 
The existence of an atmosphere extending beyond the visible photosphere is certainly 
proved by its actual appearance in the shape of a corona or ring of light, which is seen to 
surround the sun during a total eclipse.—(Trans.) 
