110 
Mr. Topping's Account of the Measurement 
Observations taken, both with the theodolite, and the Hadley, for de- 
termining the position of the base line, with respect to the meridian. 
1788. 
App. time. 
Distance of © ’s 
centre from signal 
observed. 
0 ’s altitude, 
© ’s azimuth 
Horizontal /- be- 
tween © ’s centre 
and signal. 
Angle made by 
signal with me- 
ridian. 
centre cor. 
computed. 
May 
H. / // 
0 / // 
of ft 
0 / // 
O (It 
O / // 
With theo- 
dolite,mean 
about 
of 6 sights. 
24 
7 A. M. 
• 
21 52 50 
7 1 59 18 
1 1 1 34 0 
3 33 18 
about 
mean of 6 
25 
7 A. M. 

19 22 37 
7 1 S 2 1 
68 3 35 
3 28 2 6 
about 
mean of 6 
27 
5 P. M. 
■ 
1 8 45 54 
7 1 3 40 
10 5 2b 35 
3 29 46 
about 
mean of 6 
2 9 
74- A. M. 
— 
29 20 18 
71 29 20 
111 56 8 
3 2 5 28 
about 
mean of b 
2 9 
4i P- M. 
— 
27 45 4 1 
7 1 21 34 
105 9 28 
3 29 b 
mean 
3 29 12 
mean of 4 
A. M. 
Hadley obs. 
computed 
computed 
29 
7 18 2 6 
110 35 30 
22 19 2 6 
71 b 30 
112 21 10 
3 27 40 
P. M. 
mean of 3 
computed 
computed 
29 
4 27 39 
103 42 9 
25 35 0 
7 1 ] 7 4 ° 
10 5 13 47 
3 28 33 
mean 
3 28 b 
The mean of 28 observations by the theodolite is - 3 0 29' 12" j 
The mean of 7 observations with the Hadley is 3 28 6 
The medium of both is therefore (by which the south 
end of the base is westerly, and the north end east- 
erly of the meridian) - - - 3 28 39 
N. B. The set of observations, taken as above, on the 25th of May, 
were made at the southern signal ; all the rest at the northern signal. 
