306 TRANSLATIONS AND SELECTED ARTICLES. 
third atmosphere would commonly disappear in the ocean of light 
by which the sun appears always surrounded, and which arises from 
the reflection of his rays by the particles composing the terrestrial 
atmosphere. 
A mode of resolving this doubt presented itself, by choosing the 
moment in a solar eclipse when the moon completely covers the sun. 
Just at the instant when the last rays issuing from the borders of 
the luminary disappear behind the opaque screen formed by the 
moon, our atmosphere, in the region where the two bodies are pro- 
jected, and the surrounding parts, cease to be illuminated. 
Now we see what was the principal object aimed at by the astron- 
omers who in 1842 betook themselves to the south of France, to 
Italy, Germany and Russia, where the solar eclipse of July 8 would 
be total. 
In researches of every kind, the part played by the unforeseen is 
alwaysimmense. Thus the observers were strangely surprised, when, 
after the disappearance of the last direct rays of the sun behind the 
rim of the moon, and of the light reflected by the surrounding ter-. 
restial atmosphere, they saw some rose-colored protuberances, of 
from two to three minutes in height, shoot forth. so to speak, from 
the contour of our satellite. Hach astronomer, following the ordinary 
bent of his ideas, arrived at a particular conclusion as to the cause 
of these appearances. Some attributed them to mountains of the 
moon, but this hypothesis will not bear a moment’s examination ; 
others would see in them only the effects of diflraction or refraction. 
‘But calculation is the touch-stone of all theories, and the most 
indefinite vagueness was found to accompany those of which I am 
speaking in their application to the phenomena under notice. Hx- 
planations which give us no’ precise account either of the height, 
the form, the color, or the permanence of a phenomenon, ought uot 
to find place-in Science. 
Let us take up the idea, strongly recommended for a time, that 
the protuberances of 1842 were solar mountains whose summits 
passed beyond the photosphere covered by the moon at the moment. 
of observation. 
According to the most moderate computation, the height of one- 
of these summits above the sun’s disk must have been 19000 leagues. 
I am well aware that no argument based on the enormous amount of 
this height ought to lead to a rejection of the hypothesis. But we- 
ean forcibly upset it by remarking that these pretended mountains. 
