107 



^fars. — Distance from the Sun, 141,000,000 miles ; diameter, 4,200 miles. Goes round the 

 Sun in 687 days ; spins on its own axis once in 24h. 37m. 23s. Has two satellites, discovered by 

 Professor Hall in 1877 — the outer called Deimos, and the inner called Phobos. The distance of 

 Deimos from Mars is 14,600 miles, and that of Phol)os 5,8li0 miles. Deimos goes round Mars in 

 30h. 18m., and Pliolios in 71i. 30m. 



Jiipitci- is the largest of all phuiets. Its distance from the Sun is 483,OOU,UUO miles, its 

 diameter, 80,500 miles. Goes round the Sim in nearly twelve years ; spins round its own axis in 

 9li. .^.")m. Jujiiter has live satellites, usually distinguished by the numerals 1, 2, 3, &e. The tirst 

 four were discovered by Galileo, in the year IGlU, and although the jilauet had been continuously 

 observed in every country since that time, the fifth satellite was only discovered recently at the 

 Lick Observatory, by Professor Barnard. 



For the diameters of the satellites, their distances from dupiter, and their jieriods of 

 revolution around it, we have — • 



Saturn is a wonderful object on account of the ring system surrounding its globe. Distance 

 from the Sun, 886,000,000 miles; diameter, 71,000 miles; goes round the Sun in 29^ years; 

 spins round its own axis in 10:^ hours. 



Saturn has eight satellites, the iiarticulars of which are given in the following table : — 



Uranus. — Discovered by Sir William Herschel in 1781. Distance from the Sun, 

 1,782,000,000 miles ; diameter, 32,000 miles; goes round the Sun in 84' years ; axial rotation not 

 known. 



Uranus has four satellites, which, unlike the c)tlier systems, move around the planet from 

 right to left, viz., from B. to W. : — 



