LL Semann on Geological Phenomena in the Solar System. 37 
tronomer conceived that by admitting a dark nucleus surrounded 
by a luminous atmosphere or photosphere, it would be easy to ex- 
plain the luminous phenomena presented by the sun.* On the 
other hand Leverrier from the observations made in Algiers by 
rose-colored atmosphere, which gives rise to the s or lumin- 
ous protuberances, that there exists a difference of opinion 
among obse ‘ 
ace. 
modern geological theories implicitly admit the unity of 
our planetary system, in so far as that they suppose the sun, the 
planets and ‘their satellites, to have been formed from one prim- 
itive substance; their very variable densities only show that the 
Constituent elements are grouped in varying proportions.t It is 
not necessary to suppose that each’ body of the system presents 
exactly the same chemical combinations as are known on our 
globe, for affinities will vary with the temperature and the den- 
Sities of the elements, but we may admit that a portion of any 
one of these celestial bodies brought to the surface of our ea 
to the chemical affinities which here prevail, be at length con- 
verted into @ portion of earth. : 
This unity of origin once admitted there is no longer any 
reason for denying the analogy if not the identity, of the phe- 
* This vi itution of the sun, so ingeniously defended by Arago, 
ties pest todd PegPs ey aes Kongitles for 1342, p. 510,) 2 by him there called 
Peery at William Herschel, who appears to have first clearly 
ator. 
t [Or in diferent degrees of condensation,— Translator. } 
it— 
