yOO APPENDIX. 



them are placed around the zodiac, as Aries, Taurus, &.c. 

 At March 20th, the earth as seen from the sun appears at | 

 the beginning of the sign Libra; but the sun as seen from 

 the earth, at that time, appears at the beginning of the sign ^ 

 Aries. Some of the particulars mentioned in Lesson 44 ■\ 

 should be illustrated by the instructor by means of globes, if 

 access to them can be obtained, or by such sensible objects ] 

 as he can prepare for the purpose. I 



LESSON 45. 



J 



Day and Night. Fig. 40. If the line N S, which repre- \ 



sents the axis of the earth, were always in the circle that j 



divides the light hemisphere from the dark one, the days and ; 



nights would be every where equal ; for an inhabitant at the i 



equator, and one on the same meridian towards the poles, i 



would come into the light at the same time, and immerge \ 



into darkness at the same time. But the line N S is not in \ 



this circle, but has more or less of the positions as represented \ 



at the sign Cancer or Capricorn, that is, at Dec. 23d or June \ 



21st. Here it is plain that an inhabitant at the equator does \ 



not come out of the dark hemisphere or immerge into it at j 



the same time with an inhabitant on the same meridian to- \ 



wards the poles. But while the earth is at Capricorn, an in- | 



habitant on the north side of the equator is in the light hemi- | 

 sphere longer than in the dark ; that is, the day is longer 



than the night. But at Cancer, an inhabitant on the north | 



side of the equator is in the dark hemisphere longer than in \ 



the light ; that is, the night is longer than the day : whereas j 



at the equator, in all situations of the earth, day and night \ 



are equal. 1 



LESSON 46. \ 



Changes of the Seasons. Fig. 40. The variety of the \ 



seasons depends (1,) upon the length of the days and nights; j 



and (2,) upon the position of the earth with respect to 1 



the sun. In what manner the seasons are affected by the j 



different lengths of the days and nights must be evident from \ 



what has been said above ; and as to the other circumstance, \ 



it is manifest from a mere inspection of the figure, that in j 



June the sun's rays will fall more perpendicularly upon an \ 



inhabitant on the north side of the equator than in Dec, for j 



