60 COSMOS. 



influences of solar action, in as far as they are independent 

 of the orbit and the position of the axis of our globe, has been 

 clearly to demonstrate, by an exposition of the connection ex- 

 isting between great, and, at first sight, heterogeneous phe- 

 nomena, how physical nature may be depicted in the History 

 of the Cosmos as a whole, moved and animated by internal 

 and frequently self-adjusting forces. But the waves of light 

 not only exert a decomposing and recombining action on the 

 corporeal world they not only call forth the tender germs of 

 plants from the earth, generate the green coloring matter 

 (chlorophyll) within the leaf, and give color to the fragrant 

 blossom they not only produce myriads of reflected images 

 of the Sun in the graceful play of the waves, as in the moving 

 grass of the field, but the rays of celestial light, in the varied 

 gradations of their intensity and duration, are also mysteri- 

 ously connected with the inner life of man, his intellectual 

 susceptibilities, and the melancholy or cheerful tone of his 

 feelings. " Ccdi tristitiam discutit Sol et humani nubila 

 animi serenat." (Plin., Hist. Nat., ii., 6.) 



In the description of each of the cosmical bodies, I shall 

 precede whatever consideration of their physical constitution 

 may (except in the case of the Earth) be necessary by their 

 respective numerical data. The numerical arrangement of 

 these results is nearly identical with that which was adopted 

 by Hansen,* in his admirable Revieiv of the Solar System, 

 although I have necessarily made some alterations arid addi- 

 tions in the data, from the fact that 1 1 planets and 3 satel- 

 lites have been discovered since 1837, the year in which Han- 

 sen wrote. 



The mean distance of the center of the Sun from the Earth 

 is, according to Encke's supplementary correction of the 

 Sun's parallax (Abhandlung der Berl. Akad., 1835, p. 309), 

 82,728,000 geographical miles, of which 60 go to an equa- 

 torial degree, and of which each one, according to Bessel's 

 investigation of ten measurements of degrees ( Cosmos, vol. i., 

 p. 165), contains exactly 951,807 toises, or 5710-8405 Paris 

 feet, or 6086-76 English feet. 



Light requires for its passage from the Sun to the Earth, 

 i. e., to traverse the radius of the Earth's orbit, according to 

 Struve's observations of aberration, 8' 17"'78 (Cosmos, vol. 

 iii., p. 83) ; whence it follows that the Sun's true position is 

 about 20"*445 in advance of its apparent place. 



* Hansen, in Schumacher's Jahrbuch for 1837, p. 65-141. 



