of the Diftances, the Ratio of the Axes of the Sphe- 
roid will then be that of f /6 to 577 : And the Gra- 
vity at the Pole is greater than at the Equator fay 
^th Part, or thereabouts. Which may be a Con 
formation of what is here advanced, efpeciaily to fuck 
as will not be at the Pains of going through the fore- 
going Calculations. For we may confider the Sphe- 
roid now mention'd, in which Gravity afts in a reci- 
procal Ratio of the Squares of the Diftances, as com- 
pofed of Matter of fuch Rarity, in refpeft of that at 
the Centre, that the Gravity is produced only by the 
Attraction of the Centre or Nucleus. 
XXVIII. In the foregoing Calculations, in order 
to find the Axes of our Spheroids* and to know whe- 
ther their Figure makes a fenfible Approach to that of 
the conical Ellipfts, we have had Recourfe to this Prin- 
ciple, that Gravity ought always to aft in a Direftion 
^perpendicular to the Surface. Two Reafons have 
prevail'd with us to make ufe of this Principle rather 
than the other, which confifts in the Equilibrium of 
'the Columns. The firft is, becaufe the Calculations, 
founded thereon are more fimple. The lecond is, 
that confidering the State of the aftual Solidity of the 
Earth, it fhould feem as if this Principle were the 
more indifpenfably neceffary. However, becaufe Sir 
Ifaac Newton, and all the other Philofophers, who 
•have treated about the Figure of the Earth, have taken 
it, as it were, at its firft Formation, at which Time 
they fuppofe it to have been fluid-5 we (hall here make 
'the fame Suppofttion, and we fhall affume no other 
Ratio for that of the two Axes, than that of the Sphe- 
noid, which refultsTrom a Coincidence of thefe two 
