[ 43 6 ] 
well as the proportion of the force of gravity in dif- 
ferent latitudes, as far as theory alone could limit 
them. 
The ingenious Mr. Colin Campbell made a very cu- 
rious experiment, of the diminution oi gravity from 
London to Jamaica, by means of an excellent clock, 
made by Mr. Graham, an account of which is given 
by Dr. Bradley, in N° 432 of the Philofophical 
Tranfactions, to which he has added a table of his 
own, expreffing the proportion of the force of gra- 
vity in different latitudes, and has fubjoined the pro- 
portion of the equatorial to the polar diameter of the 
earth, which fliould follow from the experiment, ac- 
cording to Sir Ifaac Newton’s principles. 
A like experiment was made by the learned French 
aftronomers, who went to the polar circle, to mealure 
the length of a degree of the meridian, by a clock 
made by the fame excellent artift, exprefly for the 
fame purpofe. 
We are likewife obliged to the gentlemen of the 
Royal Academy of Sciences at Paris, for feveral ex- 
periments made by them, in order to determine the 
force of gravity in different places, by meafuring the 
length of the fecond pendulum. 
I could not fail of being defirous of improving the 
opportunity, which my voyage to St. Helena afforded 
me, of examining this curious point, among my 
other experiments : and your Lordfhip did^ me the 
honour, not only of approving of my deiign, but 
alfo of thinking, that it was proper the very beft in- 
ftruments yet known fliould be employed tor this 
purpofe j as did alfo the Royal Society, to whom I 
communicated my intention, who were pleafed to 
e furnifh 
