Astronomy. [Lecture 18. 



during their summer, and more severe cold 

 during their winter, than we have ; and this is 

 found to be the case. 



In the last lecture I mentioned the signs of 

 the zodiac, or those which the planets traverse 

 in their revolution about the sun, and through 

 which the sun himself apparently passes in con- 

 sequence of the annual revolution of the earth. 

 To these 12 signs the names of the 12 constella- 

 tions of the zodiac are given ; we must, however, 

 not confound these signs in the heavens with the 

 constellations which bear these names. In the 

 time of Hipparchus the sign and the constella- 

 tion were nearly the same, and each of the con- 

 stellations occupied with sufficient exactness that 

 12th part of the zodiac which bore its name. 

 But at present this is not the case; the sign 

 Aries, which is the first, denotes the first portion 

 or 12th part, that is, the first 30 degrees on the 

 circle of the ecliptic, counting from that point 

 where that circle intersects the equator ; but the 

 constellation Aries is an assemblage of stars 

 which formerly corresponded with the place of 

 the sign, but which is now advanced about 

 30 degrees, so that in fact the constellation Aries 

 now occupies the place of Taurus ; Taurus that 

 of Gemini, &c. 



The first point of the zodiac, or, as it is called, 

 the first point of Aries, is at the point where 

 the equator intersects the ecliptic. It is from 

 this point that astronomers begin to count the 



