102 CHANGES OF THE SEASOI^S^. 



shine beyond a pole farther than twenty-three degrees and 

 twenty-eight minutes ; for that is the extent of his declina- 

 tion ; and when he has declination from the celestial equa- 

 tor either north or south, he must shine beyond one pole and 

 not to the other ; the days^^ therefore, will be longest in one 

 hemisphere when they are shortest in the other. 



The subject of this lesson may be illustrated, by hanging 

 any round body above or below the level of a candle so as to 

 correspond with the sun's declination. It will be seen, 

 that the light shines over one pole and does not reach the 

 other. If the ball be then turned round, it will be observed, 

 that the circles performed by any parts of the surface are 

 unequally divided by the light ; that it will be constant day 

 or night near the north pole, as the ball is depressed or ele- 

 vated, and that all the phenomena will be reversed in the 

 other, or lower hemisphere. 



Questions. — 1. What phennomena appear from the diurnal motion 

 of the earth ? 2. Under what circumstances would the days and nights 

 bo every whore of tlie same length ? — Why ? 3. Why is not the day 

 and night aKvnys equal to an inhabitant at the "equator, and to one on 

 the same meridian towards the poles ? 4. At what points does the 

 equator cut the ecliptic ? 5. When is the earth at those points of its 

 orbit ? — and what happens at these periods ? G. At other seasons ? 7. 

 What is said of day and night at the poles? 8. How may the subject 

 of this lesson be illustrated ? 9. Look at fig. 40, and illustrate th» 

 rauations in the lengths of the days and nights. 



LESSON 46. 



Changes of the Seasons, 



Obliq'uity of the Ecliptic, the angle which the ecliptic makes 

 with the equator. 



Look nature through, 'tis revolution all ; 



All change, no death. J)ay follows night, and night 



The dying day. Stars rise and set, and rise. 



Earth takes th* example ; see, the summer gay, 



With her green chaplet and ambrosial flowers, 



Droops into pallid Autumn. Winter gay, 



Horrid with frost, and turbulent with storm, 



Blows Autumn and his golden fruits away ; 



Then melts into the Spring. Soft Spring, with breatli 



Favonian^ from warm chambers of the south, 



