THE SKY. 



orbits are outside that or the earth are called " superior " 

 planets. When either of the inferior planets are between 

 the earth and the sun, they are said to be in "inferior con- 

 junction" (i c, fig. 6), and when on the opposite side, or 



PIG. 6. PLANETS SEEN IN QUADRATURE. 



behind the sun, so that a straight line from it to the earth 

 would have to pass through the sun, then it is called being 

 in "superior conjunction" (s c) ; at mid-distance, either 

 east or west, it is said to be in " eastern " or " western 

 quadrature." 



The third planet from the sun is the Earth, distant about 

 95,000,000 miles, with a diameter of 7925 miles, so that the 

 most lofty mountains (five miles high) bear about the same 

 proportion to it as would an elevation one-fourteenth of an 



