Situations determined by the great inftrument from 
Hornfey Hill and Primrofe Hill. 
254 Gen. Roy’s Account of 
angles have been reprefented by dotted lines in the plan. To 
have expreffed more of them in that way would only have 
occafioned confufion. Here it is to be remarked, that the 
diftance of Argyll Street from St. Paul’s, 9632 feet, refulting 
from the 10th and 1 ith fecondary triangles of the firft fet, be- 
comes a bafe in the quadrilateral formed by St. Paul's, Argyll 
Street, Hornfey Hill, and Primrofe Hill. Hence, by theobferved 
angles at thefe two laft Rations, and the affumed length of 
one of the unknown (ides, all the angles of the quadrilateral 
are computed, by which means, and the true length of one 
fide given, the true lengths of all the others are readily ob- 
tained. 
N - ' a 
Computation of the lecond fet of fecondary triangles. 
N° 
Triangles. 
Angles. 
Diftances of the ftations from 
the interfered object in feet. 
1. ^ 
Hornfey Hill 
Primrofe Hill 
St. Paul's • 
0 4 // 
46 42 41 
83 21 27.5 
49 55 5 * 5 
1 from St, Paul’s J 
J Church 1 
Hornfey Hill from 
Primrofe Hill 
23297.1 
17072.8 
17949.05 
p 
2e V 
Hornfey Hill 
Primrofe Hill. 
Argyll Street Qbfervatory 
23 8 34 
112 49 s 7 
44 1 2 9 
] Argyll Street Ob- f 
J fervatory \ 
23803.4 
10150.7 
* { 
Hornfey Hill 
Primrofe Hill • 
Hampftead Church 
23 33 59 
78 23 43 
78 2 l8 
] from Hampftead f 
J Church 1 
17972 
7335-5 
4. 
Hornfey Hill 
Primrofe Hill 
Mr. Duveluz’s Cupola , 
Hornfey Lane, Highgate 
29 m 3-5 
16 44 50 
134 4 6.5 
1 from Mr. Duve- f 
J luz’s Cupola 1 
I2l8l. 2\ 
7198.2 
M 
Hornfey Hill 
Primrofe. Hill 
. Iflington Church 
47 3 ° 4 2 
5 ? 42 39 
80 46 39 
| from Illington f 
j Church t 
14272.5 
13409 
N» 
