488 



SCIENTIFIC RECREATIONS. 



the earth. Then comes Mars, which, though smaller than Venus, is larger 

 than Mercury. Jupiter is the largest of all the giant amongst planets, as 

 Jove was the ruler of the gods of mythology. Saturn comes next, though 



Earth. 



O Venus. 



O Afars. 



Ceres. 



Certs. Jupiter. Saturn, 



^S? Neptune 



Fig. 528. Campara:ive size of the sun seen from the planets. 



much smaller than Jupiter, but bigger than all the rest together. Next 

 Uranus, then Neptune, larger than Uranus, but farther away from us. We 

 shall speak more in detail about these in their order separately. 



Taking the earth as I , the comparative VOLUMES of 

 the planets are as follows : 



Mercury Y V, Venus |, Mars |, Jupiter 1300, Saturn 

 900, Uranus 80, Neptune 230. Sir John Herschel 

 gives the following illustration of magnitudes and 

 distances : 



" Choose any well-levelled field or bowling green ; 

 on it place a globe two feet in diameter ; this will 

 represent the sun. Mercury 

 will be represented by a grain 

 of mustard seed on the circum- 

 ference of a circle 164 feet in 

 diameter for its orbit ; Venus 

 a pea, on a circle 284 feet in 

 diameter; the Earth also a pea 

 on a circle 430 feet ; Mars 

 a rather large pin's head on 

 a circle of 654 feet; Juno, Ceres, Vesta, and 

 Pallas grains of sand in orbits of 1,000 to 1,200 

 feet ; Jupiter a moderate-sized orange on a circle 

 nearly half a mile across ; 

 Saturn a small orange on a Fig 53C ~ sizes of r laRCU 

 circle four-fifths of a mile ; and Uranus a full-sized 

 cherry, or small plum, upon the circumference of a 

 circle more than a mile and a half in diameter " 



From an inspection of the following table the relative 

 distances of the principal planets from the sun, their 

 diameters, and other information respecting them may 



Fig. 531. Orbits of planets. * 



Fig. 529. Sizes of th 

 planets. 



