8 Astronomy. [Lecture 23. 



meridian in a given time will be to the arc of 

 the equator, passed through in the same time, 

 as 55 to 60. 



Mr. Ferguson explains this subject by a very 

 easy problem upon a common globe. If we put 

 small patches of paper, or any mark we please, 

 on every tenth or fifteenth degree both of the 

 equator and the ecliptic, as inscribed on the 

 globe, beginning at Aries T, and turn the globe 

 gently round westward; we shall find all the 

 patches or marks on the ecliptic from Aries to 

 Cancer, come to the brazen meridian sooner than 

 the corresponding marks on the equator ; those 

 from Cancer to Libra will come later to the me- 

 ridian than the marks on the equator ; those 

 from Libra to Capricorn sooner; and lastly, 

 those from Capricorn to Aries later again. The 

 marks at the beginning of Aries, Cancer, Libra, 

 and Capricorn, will come to the meridian at the 

 same time with those on the equator ; or the 

 same thing may be proved by having two little 

 balls to revolve in equal times, the one in the 

 circle of the ecliptic, and the other in that of the 

 equator. 



' 3dly, The orbit of the earth being an ellipsis, 

 of which the sun occupies one of the foci, the 

 portions of the ecliptic which the sun appears to 

 traverse are not equal to the portions which the 

 earth really passes in its orbit. 



These three causes combine at some times to 

 produce the same effect; and at others they 



