in the length of the pendulum vibrating seconds. 505 
The distance from the Signal Post to the gun marking 
Dunnose station, was found by measurement to be 120 feet, 
the gun being to the northward, and nearly in a right line 
with the south end of the base and the Signal Post. This 
being added to 1191 feet, the distance of the Signal Post 
from the south end of the Base, we have 1311 feet, for the 
distance of the gun from the south end of the Base. In the 
following triangle therefore, two sides, and the included 
angle, are given to find the remaining angles and the third 
side. 
No. 4. From the South end of Base to Dunnose Station 1311 
feet. 
South end Base, 
Dunnose Station, 
Summer house, 
67-43 35 
( 94 - 9 - 2 4 ) 
(18. 7. 1) 
to Summer house 
The following angles are for the purpose of determining 
the angle at Dunnose station, between the north and south 
ends of the base. 
o / // 
North end Base, - 1 29.39.23 
South end Base, - - 8.20.55 
Dunnose Station, - - (41-59.4 2) 
In the triangle No. 4, if from 94 0 .9'. 24" we subtract 4 i°.59'.42" 
the remainder 52 0 .9' .42'' will be the angle at Dunnose Sta- 
tion, between the Summer house and the north end of the 
Base; to which the observed angle between the north end 
of the Base and Sir Richard Worsley’s Obelisk 159°.9'.27" 
being added, we obtain 2ii°.i9 , .9 // , or for the 
