VIU. INTRODIJCTION. 



mical day comprehends a day and a night, and 

 signifies the period of the earth's proper revohition 

 round its own spindle. This double motion of the 

 earth round the sun and round its own axis, may 

 be familiarly explained by reference to the spin- 

 ning of a top, which, while it whirls rapidly 

 round its own axis, of the which the peg may be 

 regarded as one pole and the upper part the other, 

 is also making large circles on the ground. The 

 natural day and night, or periods of light and 

 darkness, are divided into Midnight Messon- 

 yctis the period fixed for each day to begin ; 

 Morning Mane; Forenoon Antemeridies ; 

 Noon Mei-idies; AFTERNOON Pomeridies; and 

 Evening Vesper. 



A Month, mensis^ is a parcel of about 30 days, 

 more or less, and is therefore the twelfth part of 

 the year. The imaginary path of the earth in the 

 heavens is divided into twelve corresponding por- 

 tions ; and the constellations which the sun inter- 

 cepts as the earth passes these portions, are called 

 Signs of the Zodiac, because the vivid imagination 

 of the antients regarded these groups of the stars 

 as giving the notion of the figures of animals ; but 

 it is not till about the third week of each month 

 that the sun enters a new sign. Thus he enters 

 Aries or the Ram T, March 20 ; Taurus the 

 BuU b, April 19 ; Gemini the Twins n, May 21 ; 

 Cancer the Crab 25, June 22 ; Leo the Lion SI, 



