HEAVENLY BODIES 



469 



Adding the one day to every four years makes the average length 

 of a year 365 days and 6 hours. This makes the year 11 min- 

 utes and 14 seconds too long, which amounts to over 3 days in 

 400 years. The year at the beginning of every century is not a 



FIG. 358. Position of the earth in its orbit each month. What does solstice 

 mean? What does equinox mean? Why is December 21st called the 

 winter solstice? June 21st the summer solstice? March 21st and Septem- 

 ber 23rd the equinoxes? 



leap year unless it is divisible by 400 an arrangement which corrects 

 the discrepancy. 



Meteors. On some starry night you may have seen a meteor 

 dart across the sky. Some people call these " falling stars " or 



