94 THE SUN. I 



On nature, write with every beam, His praise. 



Soul of surrounding worlds ! — i 



'Tis by thy secret, strong, attractive force, 1 



As with a chain indissolubly bound, .; 



Thy system rolls entire ; far from the bourn j 



Of utmost Herschcl, wheeling wide his round i 



Oi eighty years ; to Mercury whose disk \ 



Can scarce be caught by philosophic eye, \ 



Lost in the near effulgence of thy blaze. Thomson. j 



The sun is a fountain of light that illuminates the world ; | 

 it is the cause of that heat which maintains the productive ' j 

 power of nature, and makes the earth a fit habitation for i 

 man. The figure of the sun is a spheroid, higher under the • \ 

 equator than about the poles ; and his diameter is computed \ 

 to be nearly nine hundred thousand miles. His solid bulk \ 

 is more than a million of times larger than that of the earth. 1 

 The sun has two motions ; the one is a periodical motion, in 

 an elliptical or very nearly circular direction, round the com- ' 

 rrtbn centre of all the planetary motions ; the other is a revo- '■ 

 lution upon its axis, which is completed in about twenty-six ' 

 days. That the sun has a rotation round his axis is made 1 

 evident by the spots seen on his surface. Some of these 

 spots have made their first appearance near the edge or \ 

 margin of the sun, and have been seen some time after on ; 

 the opposite edge ; whence, after a stay of more than thir- 

 teen days, they have re-appeared in their first place, and ; 

 taken the same course over again. These spots were en- | 

 tirely unknown before the invention of telescopes, though " 

 they are sometimes of sufficient magnitude to be discerned , 

 by the naked eye. Some have been so large, as by compu- ; 

 tation to be*capable of covering the continents of Asia and 

 Africa, the whole surface of the earth, or even five times 

 its surface. The sun has commonly been considered a 

 globe of fire ; but this has been doubted by modern astrono- 

 mers. The celebrated Herschel considers the sun as a most 

 magnificent hahitable globe, surrounded by a very extensive ' 

 atmosphere, which consists of elastic fluids that are more or 

 less lucid and transparent ; and of which the lucid ones fur- 

 nish us with light. The appearances, called spots in the 

 sun, he considers as real openings in the luminous clouds i 

 of the solar atmosphere. • | 



