( 25 2 ) 
cc through the Axes are unequal, thefe Axes, and confe- 
“ quently the Lengths of the Pendulum which vibrates 
“ i* 1 ^hefe Cycloids, are proportional to the accelerating 
u f orces of their Gravities. 
“ B y this if we know the Length of a Pendulum 
<e which performs its Vibrations in a given Time, in 
any one Part of the Earth, it is eafy to determine the 
Length of a Pendulum, which performs its Vibra- 
f i° ns in the fame Time in any other Part of the Earth • 
<c as for Example, the Length of a Pendulum, which v> 
“ brates Seconds at Tar is, is three Foot eight Lines 
<c and a Half, let it be requir’d to find the Length of a 
<e Pendulum, which vibrates Seconds at the /Equator. 
<c Becaufe the Gravity at the Poles is to the Gravity at 
“ the ./Equator, as 691 is to 689 ; therefore the De- 
44 creafe of Gravity at the .Equator is Parts of the 
“ whole Gravity j but, as 1 have before demonftrated,the 
“ Decreafe of Gravity at the ./Equator is to itsEncreafe 
“ in any other Latitude, as the Square of the Radius is 
<c to the Square of the Sine of the Latitude, now the 
“ Latitude of Tar is being 48° 4/, its Sine is 7 5. 18/, 
“ and therefore the Square of the Radius is to the 
ce Square of the Sine of the Latitude as 1000000 to 
“ 565148, but as icooooo is to 565148, fo is 3.000 
“ the Number which reprefents the Decreafe of Gra- 
<c vity at the ./Equator to 1. 695, the Number which 
“ reprefents its Encreafe at Taris , which added to 689 
(C the Gravity at the /Equator, makes 690.695, the Num- 
<c ber which will reprefent the Gravity at Taris. But 
cc 1 have already fliew’d, that as the Gravity at Taris 
“ is to the Gravity at the ./Equator, fo is the Length of 
“ a Pendulum which vibrates Seconds at Taris , to the 
“ Length of a Pendulum tliat yibrates Seconds at the 
xc /Equator, that is as 690, 695' to 689, fo is 36,708 the 
u Length of a Pendulum at Taris , which performs its 
“ Vibra- 
