refte'&in'g the Caufe of the Tides. I45 



poles. To a leer tain this point, fome of the moft celebrated 

 mathematicians of Europe were appointed to determine, by 

 actual meafurement, the length of a degree both at the equator 

 and at the pole. They found that the polar degrees exceeded 

 the equatorial, and concluded they muft confcquentlv be parts 

 of a larger circle, and, of courfe, that the earth was flattened 

 at the poles. This was univerfallv conlidercd as decinve of 

 the queftion, till the genius of our Frenchman detected a grofs 

 and palpable error in the calculation, which had efcaped their 

 accurate knowledge and penetration : but, as the elongation 

 of the poles conltitutes a leading feature in the new theory, 

 I fhall give it a more detailed examination. 



This polar elongation, as he conceives, is fupported by 

 four direct and pofitive proofs : — the firft geometrical, upon 

 which he lays the greateft ftrefs, and upon which he has 

 flaked his reputation ; the 2d, atmofpherical ; the 3d, nau> 

 tical ; the 4th, aftronomical : of all which in order. 



The 1 ft, or geometrical proof, is what he calls a demons 

 ftration founded on the meafurement of the earth, ancL 

 admitting the polar degrees to exceed the equatorial : here, 

 follows the demonftration : If you place a degree of tliQ 

 meridian at the polar circle on a degree of the fame meridian 

 at the equator, the firft degree, which meafures 57,422 

 fathoms, will exceed the 2d, which is 56,748 fathoms, by 

 674 f confcquentlv, if you apply the arc of the meridian 

 Contained within the polar circle, being 47 , to an arc of 

 47 of the fame meridian at the equator, it would produce 

 a considerable protuberance, its degrees being greater. 



To render this more apparent, let us always fuppofe 

 that the profde of the earth, at the poles, is an arc of a 

 circle containing 47 ; is it not evident, if you trace a curve 

 on the in fide of this arc, as the academicians do when they 

 flatten the earth at the poles, that it muft be fmailcr than 

 the arc within which it is defcribed, beino- contained in it ? 

 And the more this curve is flattened the fmaller it becomes. 

 Of confequence, the 47 of this entire curve wilt be indi- 

 vidually fmaller than the 47 of the containing arc. But as 

 the degrees of the polar curve exceed thofe of the arc of a 

 circle, it mull follow that the whole curve is of greater extent 



Vol. VI If. U than 



