270 SPECIAL RESULTS IN THE URANOLOGICAL 



(Kosmos, Ed. iii. s. 91, and 127 Anm. 52, Eng. ed. p. 73, 

 and Note 140), whence the true place of the Sun is 20".445 

 in advance of the apparent place. 



The apparent diameter of the Sun at its mean distance 

 from the Earth is 32' 1".8 : only 54".8 more than the ap- 

 parent diameter of the disk of the Moon at her mean distance 

 from the Earth. At our perihelion, in the winter when 

 we are nearest to the Sun, its apparent diameter is increased 

 to 32" 34". 6 ; at the aphelion in the opposite part of the 

 year, when we are farthest from the Sun, its apparent dia- 

 meter is diminished to 31' 30".l. 



The true diameter of the Sun is 192700 German, or 

 770800 English geographical miles; or, more than 112 

 times greater than the diameter of the Earth. 



The mass of the Sun is, according to Encke's calculation 

 of Sabine's pendulum formula, 359551 times that of the 

 Earth, or 355499 times the mass of the Earth and Moon 

 taken together (Yierte Abh. iiber den Cometen von Pons in 

 den Schr. der Berl. Akad. 1842, S. 5) ; this would make 

 the density of the Sun only about one quarter (more exactly 

 0-252), of that of the Earth. * . 



The Sun has 600 times more volume, and according to 

 Galle, 738 times more mass, than all the planets together. 

 In order to convey in some degree a sensible image of 

 the magnitude of the body of the Sun, it has been remarked 

 that if we were to imagine the globe of the Sun entirely 

 hollowed out, and the Earth placed in its centre, there 

 would still be room for the Moon's orbit, even though the 

 serni- diameter of the said orbit were to be increased by 

 upwards of 40000 (160000 English) geographical miles. 



The Sun rotates round its axis in 25 J days; its equator 



