176 MtfctUmea Cttriofa. 



And it mull needs be fo. For, fince this 

 equally refpefts all points of the Horizon j let 

 the Refraction be what it will, the whole Ho- 

 ri%jon can be but a Circle : So that there is 

 no room for the breadth of a thing (as to 

 the Angle at the Eye) to be made greater, 

 whatever its Tallnefs may (the Refraction 

 not equally affecting all parts in the Circles 

 of Altitude^) Nor is there any reafon why 

 this lhould rather thruft the other, than that 

 the other thruft this, out of place. 



Whereas, in the Altitude, it is otherwife : 

 For while what is near the Horizon is inlarg- 

 ed, that which is further off is thereby con- 

 traded : which as to the Azimuth or Horizon- 

 tal Pofition cannot be. 



In Spectacles indeed it is otherwife \ for 

 they reprefent the Object: every way enlarg- 

 ed ; and do thereby hide the adjacent parts. 

 But in Refraction by Vapours, fuppofing all 

 parts of the Horizon equally affe&ed by them, 

 one part cannot be expanded in breadth 

 (whatever it may be as to the heighth) with- 

 out thrufting out another ffor the whole 

 Horizon can be but a Circle) and, why one 

 part rather than another ? 



Unlefs we would fay (as perhaps we may, 

 if there mail appear a neceflity for it) That 

 the Rays of a lucid Body do expand them- 

 felves every way to the prejudice of the parts 

 adjacent, by covering them. 



But fuppofing (which I am apt to believe, 

 till the contrary mall be evinced by Experi- 

 ment) that the Sun or Moon's apparent Dia- 

 meter taken by Inftrument near the Horizon, 

 is the fame as taken in a higher Pofition, (I 



mean 



