236 ASTRONOMY. 



THE SUN. 



" Mighty being ! brightest image and representative of the Almighty ! 

 supreme 'of the corporeal world ! Unperishing in grace and of undecay- 

 ing youth !" 



Astronomical calculation proves to us the immense magnitude of this 

 luminary, which, to the eye, appears little larger than the earth's 

 attendant moon ; but its diameter is reckoned to be five hundred and 

 thirty-nine times larger than all the planets put together! It is the 

 source of light and heat to all the planets. Of the Malculae or dark 

 spots, they are supposed to be occasioned by the smoke and opaque 

 matter, thrown out by volcanoes or burning mountains of immense 

 magnitude, and that when the eruption is nearly over and the smoke is 

 dissipated, then the fierce flames are exposed, and they appear like 

 feculce or luminous spots. Though the sun is the central body of the 

 system, yet it has been well ascertained that tha various attractions of 

 the circumvolving planets, give it a partial motion round the centre of 

 gravity of the system. 



The degrees of light and heat which the planets derive from the sun, 

 are always communicated in greater or smaller portions, not only in 

 proportion to their distance from it, but according as its position is more 

 or less oblique to any given part of the planets' surface. This is the 

 reason that we, who live at such a distance from the equator, have the 

 coldest weather when the sun is nearest to us, viz. in winter; and the 

 reason of this is obvious; for as the eccentricity of the earth's orbit 

 bears but a trifling proportion to the distance of the earth from the sun, 

 and therefore, of itself, can occasion no great difference of heat and cold 

 to us in the different seasons, it follows that the remarkable difference 

 which we experience must be owing to the relative directions of the 

 solar rays. 



Thus in winter, the sun's rays fall so obliquely upon us that any 

 given number of them will not only fall with less force, but must be 

 spread over a greater portion of our part of the earth's surface. Besides, 

 the sun's continuance above the horizon being considerably shorter in the 

 winter, and the nights much longer, must of course, further contribute 

 to increase the cold. 



Some may imagine from this, that as the sun always gives most heat 

 when his rays are the most perpendicular, the hottest part of our 

 summer should be when the sun is in the first degrees of Cancer; j. <., 



