( 3i* ) 
Suppofitions, I colleft from the forementioned Qbfer- 
vations, that, if the Length of a Ample Pendulum 
(that fwings Seconds at London) be 39.12 6 Ehglijb 
Inches, the Length of one at the ^Equator, would 
be 39.00, and at the Poles 39.206. And (ab- 
ftraffing from the Alteration on account of different 
Degrees of Heat) a Pendulum Clock that would 
go true Time under the JEquator, will gain 3 > 48"' in 
a Day at the Poles; but the number of Seconds which 
it would gain in any other Latitude, would be to 
3'. 48"! nearly, as the Square of the Sine of that Lati- 
tude is to the Square of the Radius : From whence it 
follows, that the Number of Seconds which a Clock 
will lofe in a Day, upon its Removal to a Place nearer 
to the Equator, will be to 3' 48";; nearly, as the Dif- 
ference between the Squares of the Sines of the Lati- 
tudes of the two Places to the Square of the Radius. 
Thus the Difference of the Squares of the Sines of 
9 i°j, and 1 8°, the Latitudes of London, and Black- 
River being to the Square of the Radius, as 118 to 
228-;, the Clock will go T 98" in a Day flower at 
Black-River than at London, as wasfound byOb- 
fervation. 
It may be hoped, that Mr. Campbell * s Succefs in 
this Experiment, and the little Trouble there is in 
making it, will induce thofe Gentlemen who may 
hereafter carry Pendulum-Clocks into diftant Coun- 
tries, to attempt a Repetition of it after his manner; 
that is, by keeping or reftoring the Pendulums of 
their Clocks to the fame Length in the different 
Places, and carefully comparing them with the Hea- 
vens, and at the fame Time taking notice of the differ- 
ent Degrees of Heat, by means of a Thermometer. 
From 
