VIII. 
AN ACCOUNT OF THE EXPERIMENTS TO DETERMINE THE ACCELERATION 
OF THE PENDULUM IN DIFFERENT LATITUDES. 
A FULL and detailed report of these experiments has been presented to the 
Royal Society at whose desire they were undertaken, and will be published 
in the Philosophical Transactions ; the present statement is, therefore, con- 
fined to a brief notice of their object, nature, and results. 
Were the figure of the earth truly spherical, a pendulum would make the 
same number of vibrations in a given time, under like circumstances of 
temperature, and of atmospherical pressure, and at equal heights above the 
level of the sea, in every part of the globe, because the force of gravity 
which governs the vibrations would be always the same, being at equal dis- 
tances from the centre of the earth. 
The accidental discovery that a pendulum, on being removed from Paris 
to the neighbourhood of the Equator, increased its time of vibration, gave 
the first step to our present knowledge, that the Polar axis of the globe 
is less than the Equatorial, and that the force of gravity at the surface of the 
earth increases progressively from the Equator towards the Poles. 
It has been deemed an important object to science, to determine by expe- 
riment the precise amount of the deviation of the figure of the earth from a 
perfect sphere. This purpose has been attempted either by the actual mea- 
surement and comparison of distant degrees of latitude on a terrestrial meri- 
dian, or by ascertaining the variation in the force of gravity in different latitudes 
by means of a pendulum, and thence inferring, by certain known methods, 
the diminution of gravity from the Pole to the Equator, and the conse- 
quent ratio of the Equatorial to the Polar axis. 
Such was the object of the present experiments. Their nature may be 
