in the length of the pendulum vibrating seconds. 407 
The observed arc between Greenwich and Arbury Hill, is 
o°.44'. 48^,19, which being added to the latitude of Green- 
wich, gives 52°.i3'.26",2o for the latitude of Arbury Hill by 
the Trigonometrical Survey, which differs o",48 in excess, from 
the latitude given by the Repeating Circle. 
We cannot then but conclude, that the observations 
made with the zenith sector, both at Clifton and Arbury Hill, 
are free from any material error ; and as the difference be- 
tween the latitudes of Clifton by the Zenith Sector, and by the 
Repeating Circle, w-as o",2g, that by the Zenith Sector being 
in defect, and of Arbury Hill o",48 in excess, it is extremely 
probable that the error of observation at either of these 
stations does not amount to so much as four-tenths of a 
second. 
A base of go6 feet was carefully measured near the foot of 
Arbury Hill, for the purpose of finding the distance on the 
meridian of this station from the pendulum ; which distance, 
as appears in the Appendix, v^as 3048 feet, the pendulum 
being so nearly in the meridian of the station, that no deduc- 
tion on account of its bearing is necessary. The arc corres- 
ponding to 3048 feet, is go", 06, which being subtracted from 
52 0 . 13'. 25 ',32, leaves 52 0 . 12'. 55", 32 for the latitude of the 
pendulum. 
Latitude of the Station at London. 
The latitude of Mr. Browne's house in Portland Place, 
deduced from the Trigonometrical Survey, as detailed in the 
Philosophical Transactions for 1818, is 5i°.3i / .8",4. 
