38 L. Semann on Geological Phenomena in the Solar System. 
nomena which have accompanied the formation of the sun and 
the planets, at least of those whose density approaches the nearest 
to that of the earth. All of them must have passed by cooling 
from a state of igneous fluidity to a solid condition, and their 
following reflections, 
e admit a similar geological (or chemical) constitution for 
the various bodies of the solar system, and from this conclude 
that the phenomena which have accompanied their formation 
and their successive transformations, must have been similar. 
Thus the planets and satellites whose density is near to that 
of our earth may be supposed to have passed through the dif- 
ferent stages of liquid and solid incandescence, of the successive 
liquefaction of portions of their gaseous envelopes, and to have 
finally been the seat of an organic creation. 
Of these planetary bodies the best known to us is the moon, 
and we anal now inquire to what extent our slight knowledge 
of it is in accordance with the observations made on our earth, 
and with the present state of the sun as supposed by Mr. Lever- 
rier. It is wali known that astronomers, so soon as they became 
d of good telescopes, discovered mountains and plains (or 
seas) on the surface of the moon, and the immediate application 
f these names shews the great resemblance which was 8 
to exist between the surfaces of the moon and the earth. 
Se ae 
