1 6 .SWIFT MOTION OF PLANETS. 



a surface velocity of more than 15 miles per 

 minute at the equator. 



It is to be remembered that our earth is one 

 of the smaller planets, being only -^~ part of the 

 magnitude of Jupiter, and that there are more 

 than one hundred and fifty planets and asteroids 

 all swiftly revolving as working parts of the 

 mechanism of the solar system. 



The vast planet Jupiter, 89,000 miles in diam- 

 eter, rotates in io}4 hours, and has a surface 

 velocity of nearly 450 miles per minute. 



The annexed table shows the comparative 

 magnitude of our earth and the other planets of 

 the solar system, and also their relative veloc- 

 ities : 



