C *5* .) 
«« Gravity of thofe Bodies, which are within the Earth, 
‘‘ will be dire&ly as their Diltance, both which do beft 
“ agree with the obferv’d Phenomena of Nature j then 
‘‘ will the Gravity at the Equator be to the Gravity 
Ci at the Poles as 689 to 691, which Numbers, in this 
Hypothecs, do alfo exprefs the Proportion of the Dia- 
“ meter of the Earth, drawn through its Poles, to its 
“ Diameter drawn in the Plane of the iEquator. 
“ It is upon the Account of this Diminution of Gra- 
cC ' vity, according as we approach the ./Equator, that 
“ Pendulums of the fame Lengths in different Latitudes 
Cc take different Times to perform their Vibrations j 
tc for becaufe the accelerating Force of Gravity is lefs 
“ at the /Equator than under any Parallel, and under 
“ any Parallel it is {till lefs than under another which 
“ is nearer the Poles •, it does plainly from thence fol- 
low, that a Body plac’d in the ./Equator, or in any 
« other Parallel, will take a longer Time to defcend thro’ 
“ an Arch of a given Circle, than it wou’d do at the 
“ Poles, and the farther a Body is remov’d from the 
« Poles, the longer Time it will take to defcend through 
“ any given Space. 
« From hence it follows, that the Length of Pendu- 
« lums, which perform their Vibrations in equal Times 
“ in different Latitudes, are dire&ly as the accelerating 
“ Forces of their Gravities; for the Time a Body takes 
« to defcend through an Arch of a Cycloid, is to the 
«■ Time it will take to fall through the Axis of the Cy- 
« cloid always in a given Proportion, viz. as the Semi-- 
« periphery of a Circle is to its Diameter by the xyth 
“ Prop, of Hay gen ' s Horologium Ofcillatorium ; and 
“ therefore when- the Times in which a Body defcends 
« through the Axes of two different Cycloids are equal, 
« the Times of the Defcent through the Cycloids will 
“ be alfo equal , but when the Times of the Defcent 
“ through 
