PHYSICAL ANp LITERARY. 191 



Art. IV. 



Of the Caiife of the Variation of the Obliqui- 

 ty of the Ecliptic, by Co 1 1 « M L a u r i n, 

 late Fellonv of the Royal Society, and 

 F*ofeJor of Mathematics in the Untver- 

 fity of Edinburgh. 



THE Ffenph aftronomers in Peru, and 

 Dr Bevis at London, and others elfe- 

 where, have endeavoured to determine 

 the obliquity of the ecliptic with greater 

 accuracy than former aftronomers ha4 

 attained to. The refult of their obferva- 

 tions makes it to be now about 23° 29^ 

 28"|. It had been for fome time reckon- 

 ed 23° 29 29'' i and before that, 23° 29? 

 30"; and, by fome antient aftronomers, 

 19 or 20 minutes greater. MelT- Caflini 

 and Bradley had found it to vary a little : 

 And this has given occafton to a notion, 

 that it is decreafing continually ; that 

 there was a time when the axis of the earth 

 lay in the plane of the earth's orbit y that 



it? 



