( 19 * ) 
ftion } and proceed to an Cbfervation that he makes af- 
terwards, viz, lt JV e mufttake care to obferve in the 
“ foregoing ‘Proportions and Corollaries , that the 
Ct Comparifon is always made between two flmilar 
“ Points of Latitude , taken upon the two Spheroids , 
“ or upon one of the Spheroids and the Sphere , 
“ between the A Equator and the Poles , in refpeft to 
“ the Centrifugal Force upon the Equator of any 
one of thefe Spheroids , or of the Sphere. For if 
“ we only compar'd abfolutely the Centrifugal Force 
“ of a Point of the JEqudtor of the one , to the Cen - 
“ trifugal Force of a correfpondent Point of the AE- 
“ quator of the other , it is plain that it wou'd be 
“ greater upon a flatted Spheroid , than upon a Sphere , 
ct upon an oblong Spheroid of the fame Soli- 
V dity, in the Ratio of the great Axis of the gene - 
ct rating Ellipfe of the flatted Spheroid , to the c Di- 
c< ameter of the Sphere , or to the fhorter Axis of the 
“ generating Ellipfe of the oblong Spheroid. And in 
cc all Likelihood \ this mufl be the Reafon that has 
tc made others , who have treated of this Subject, to 
64 imagine the very contrary of what I have demon - 
“ flrated. 
As Monf. Mairan confiders the Earth at reft, in the 
Conftrudion for his Demonftration above quoted, and 
afterwards obferves what Effed the Centrifugal Force 
will have upon Bodies on its Surface, to diminilh the Gra- 
vity, with which they endeavour to defeend in their 
Line of Tendency R P : He Ihou’d not only have taken 
notice (as he has done) that the whole Centrifugal Force 
N R is not to be fubftra&ed from the Gravity at R, as 
the whole Centrifugal Force CD is to be fubftraded 
from the whole Gravity at D, becaufe of the Obliquity 
of R N to P R ; but he ftiould have obferv’d aifo, that 
the Obliquity of the Plane of the Parallel N R,in which 
2 the 
