( 3 11 ) 
du£ting therefore 8"i, on account of the greater Heat 
in Jamaica , there remains a Difference of i' 
which muff neceffarily arife from the Diminution of 
Gravity, in the Place neareft the Equator. 
I have allowed the Clock to have loll fomewhat 
more, on account of the Difference of Heat, than the 
mean Heights of the Thermometer may feein to re- 
quire, upon a Suppofition, that the total Heat of 
the Days, compared with the Cold of the Nights, 
bears a ' greater Proportion in Jamaica , than Lon- 
don ; but if that Suppofition be not admitted, then 
the Clock in Jamaica , mull have gone rather more 
than i 1 58" in a Day flower than in England. 
Mr. Campbell's Obfervations were made at Black- 
River, in 1 8°. North Latitude. Now if wefuppofe, 
with Sir Jfaac Neve ton, that the Difference in the 
going of the Clock, is owing to the greater Elevation 
of the Parts of the Earth towards the ^Equator, it will 
follow from thefe Obfervations, and what is delivered 
by him in the 20th Prop, of the 3d Book of his 
Principia , that the /Equatorial Diameter is to the 
Polar, as 190 to 1893 the Difference between them 
being 41I Miles ; which is fomewhat greater than 
what Sir JJ'aac Newton had computed from his The- 
ory, upon the Suppofition of an uniform Denfity in 
all the Parts of the Earth. 
I Ihall not enter into the Difpute about the Figure 
of the Earth, but at prefent fuppofe, with Sir Ifaac 
Newton, that the Increafe of Gravity, as we recede 
from the iEquator, is nearly as the Square of the 
Sine of the Latitude ; and that the Difference in the 
Length of Pendulums, is proportional to the Aug- 
mentation, or Diminution of Gravity. Upon thefe 
