( 2 9 ^ ) 
Paris and at the /Equator in a fpherical Earth, will be 
g — c~ f- 1 — g — e 1 — / ^ 
Thirdly , Let the Centrifugal Force at the /Equator 
of the oblong Spheroid be call’d c, and the Centrifugal 
Forceat Paris be call’d c — l + m - f the Difference 
or the Diminution of Gravity at “Paris, and at the ,E- 
quator, in an oblong fpheroidical Earth, will be ? r 
I 1 — ■ -y 
K ' ( — l m n — / — — j — u. 
Now, if Gravity Ihou’d in every Cafe be equal to* 
it is evident, that the Ihortening of Pendulums, at the 
/Equator, Wou’d be greater in the oblong Spheroid, than 
in the Sphere, or in the flatted Spheroid ; becaufe as 
the Lengths of Pendulums diminifh with the Gravity 
thofe Lengths will ba at Paris and at the /Equator] 
when compar’d, as* — c + - 1 tog— c~+? in the 
flatted Spheroid j as ^ — c — 1 — / — |— rsi to t? f r J 1 
in the Sphere, and as*— '<•_ m + »' to* — c in 
the oblongSpheroid ; and confequently,fromwhatM.A/«i- 
ran has demonftrated this Ratio of* — 
v g A~, C ’ hdng a Pi ter th3n eitller of tlle others, The 
Pendulums muft be Ihortened in the oblong Spheroid. 
But as the Force of Gravity is Jefs at the Equator of 
the flatted Spheroid, than at the /Equator of the Sphere, or 
of the oblong Spheroid of thefame Solidity: let us exprefs 
its Qjianttty in the three Cafes by g sr mdtr Mr m,l 
we fhall then find the Lengths o/t the pfndulmntat’the 
Equator of the three Solids, as*— j-_r+T, 
f + 1, and * 4- j _ c - confequently the Lengths of 
Pendulums 
