SATURN. 



533 



as they become inclined, they appear broader (fig. 592). 



may be formed of vapour, but the outer 



ones are of something more solid, as 



the shadows they cast upon the planet, 



and it casts upon them, at certain 



times (figs. 593 and 594). 



Saturn possesses eight moons, 

 seven of them revolving in orbits on 

 the plane of the rings, but one is more 

 inclined. These eight satellites have 

 been named as follows : 



The inner 



ring 



Fig, 593. Ring shadow. 



But these eight moons are not so interesting as those belonging to 



Jupiter, because the great distance they 

 are away precludes much examination 

 of them. They vary much in size, Titan 

 being the largest, and perhaps equal to 

 Mars, lapetus being next in magnitude. 

 The light of these satellites and the 

 i ings is no doubt very great in the ag- 

 gregate, and must have a magnificent 

 appearance in the heavens (compare 

 page 493). Very likely there are other 

 attendants upon Saturn, but owing to 

 the brilliancy of the rings it is impossible to distinguish them. 



594. King shadow. 



URANUS. 



Uranus was discovered by Herschel in 1781, and has been called after 

 its discoverer, and sometimes the " Georgium Sidus." It revolves at an 

 enormous distance from the sun viz., 1,753,000,000 of miles. It takes 

 about eighty-four of our years (30,686 days) to go round the sun, ancl 

 possesses four moons. It is very much larger than the earth about four 

 times the diameter, and forty times its volume. We can only speculate 



