FROM THE ORDNANCE TRIGONOMETRICAL SURVEY. 
617 
Stations. 
Latitudes. 
Observed. 
Spheroid 
(A). 
Diff. 
Obs. — Cal. 
Spheroid 
(B). 
DifF. 
Obs.— Cal. 
Saint Agnes 
49 53 33-94 
30-78 
-3-16 
32-93 
-POl 
Goonhilly 
50 2 50-07 
45-35 
-4-72 
47-42 
-2-65 
Hensbarrow 
50 22 61-84 
58-81 
-3-03 
60-73 
— 1-11 
Port Valley 
50 35 43-20 
43-17 
-0-03 
44-95 
+ 1-75 
Week Down 
50 35 51-42 
50-28 
-1-14 
52-06 
+ 0-64 
Boniface Down 
50 36 10-56 
9-63 
-0-92 
11-41 
+ 0-86 
Dunnose 
50 37 7-13 
3-75 
— 3-40 
5-53 
-1-62 
Black Down 
50 41 8-89 
10-29 
+ 1-40 
12-04 
+ 3-15 
Southampton 
50 54 46-97 
47-23 
+ 0-26 
48-88 
+ 1-91 
Greenwich 
51 28 38-30 
38-30 
0-00 
39-70 
+ 1-40 
Hungry Hill 
51 41 10-26 
11-47 
+ 1-21 
12-94 
+ 2-68 
Feaghmaan 
51 55 22-85 
20-30 
-2-55 
21-68 
-1-17 
Precelly 
51 56 45-18 
44-76 
-0-42 
45-99 
+ 0-81 
Arbury Hill 
52 13 27-01 
27-29 
+ 0-28 
28-36 
+ 1-35 
Forth Mountain 
52 18 57-91 
56-83 
-1-08 
57-93 
+ 0-02 
Delamere 
53 13 18-56 
17-27 
-1-29 
17-93 
-0-63 
Clifton Beacon 
53 27 30-27 
27-02 
-3-25 
27-56 
-2-71 
South Berule 
54 8 56-40 
57-60 
+ 1-20 
57-87 
+ 1-47 
Tawnaghmore 
34 17 41-34 
39-61 
— 1-73 
39-93 
— 1-41 
Burleigh Moor 
34 34 19-75 
15-74 
— 4-01 
15-80 
-3-95 
S. end of LoughFoyleBase 
55 2 38-74 
33-93 
— 4-81 
33-86 
-4-88 
Ben Lomond 
56 11 26-27 
25-26 
— 1-01 
24-64 
— 1-63 
Kellie Law 
56 14 51-43 
53-69 
+ 2-26 
53-02 
+ 1-59 
Ben Heynish 
56 27 16-88 
19-64 
+ 2-76 
18-95 
+ 2-07 
Great Stirling 
57 27 49-12 
50-14 
+ 1-02 
48-94 
— 0-18 
Cowhythe 
37 40 68-92 
60-49 
-8-43 
59-20 
-9-72 
Monach 
58 21 20-84 
23-54 
+ 2-70 
22-01 
+ 1-17 
Ben Hutig 
58 33 6-47 
5-12 
-1-35 
3-47 
-3-00 
North Rona 
59 7 13-19 
17-67 
+ 2-48 
15-80 
+ 0-61 
Balta 
60 45 1-73 
7-16 
+ 5-41 
4-51 
+ 2-76 
Gerth of Scaw 
60 48 56-43 
61-82 
+ 5-39 
59-15 
+ 2-72 
Saxavord 
60 49 38-58 
41-99 
+ 3-41 
39-31 
+ 0-73 
Arcs of Meridian. 
The two longest meridional lines in the triangulation are from Dunnose, in the 
Isle of Wight, to Saxavord in the Shetland Isles, and from St. Agnes’ Lighthouse, in 
the Scilly Islands, to North Rona ; the lengths and amplitudes are as follows : — 
Length. 
Astronomical 
amplitude. 
Dunnose to Saxavord 
feet 
3729335-8 
3370394-2 
10 12 31-43 
9 13 41-25 
St. Agnes to North Rona 
Arc of Parallel. 
The volume of the Greenwich Observations for 1845 contains the account of the 
determination of the longitude of Feaghmaan, a station in the Island of Valencia on 
the west coast of Ireland, by the transmission of chronometers. 
The whole arc was subdivided- by two intermediate stations, of which one was the 
4 M 2 
