the 'Trigonometrical Operation . 2 zy 
lengths of degrees of great circles and of longitude has been 
conftru£ted for middle latitudes only, extending from 42 0 to 
52°, Without the help of fuch a table, the new longitudes of 
fome intermediate places, which we fhall have occafion here- 
after to compare with the old, could not have been fo accu- 
rately computed as was wifhed. Now, although it is be- 
lieved, that this table will be found to anfwer nearly in that 
zone of the earth for which it is intended ; yet it is only 
offered for temporary ufe, until future obfervations of the pole- 
liar in the fame parallel, but on longer diftances than our recent 
feries of triangles afforded, or the extenfion of operations of 
the fame nature with ours into remoter latitudes, fhall have 
furnilhed data for one more correft. 
Table of the degrees of great circles and of longitude for 
middle latitudes. 
Places. 
Latitudes. 
Deg. of great cir- 
cles, perp. to the 
meridian in fath. 
Degrees of longitude 
in fathoms. 
0 
/ 
// 
Diff. 
Diff. 
4a 
0 
0 
61 170.5 
1 
h 0 
45458-5 
1 
43 
0 
0 
61178. 
I 
7*5 
44742.8 
1 
7 * 5-7 
South of France 
43 
32 
0 
61182.5 
} 
4*5 
44355-7 
} 
387.1 
44 
0 
0 
61186.5 
} 
4 - 
44013.9 
} 
341.8 
45 
0 
0 
61195. 
} 
8-5 
4327 I -4 
} 
742-5 
46 
0 
0 
61203. 
} 
8. 
42515-2 
} 
756.2 
47 
0 
0 
6x211.5 
} 
8-5 
4 X 746 >I 
} 
769.1 
48 
0 
0 
61220. 
} 
8-5 
4O964.2 
} 
781.9 
Paris Royal Obfervatory 
48 
5° 
14 
6x227.5 
} 
7-5 
40303.2 
} 
662.0 
49 
0 
0 
6x229, 
} 
I *5 
4OI69.8 
} 
j 32.4 
50 
0 
0 
61237.5 
} 
8-5 
39362.8 
} 
807.0 
5 1 
0 
0 
61246.5 
} 
9 - 
3 8 542.7 
} 
820.1 
M near Dunkirk 
5 1 
1 
48-3 
61246.7 
} 
0.2 
38518.8 
} 
23-9 
Dunkirk 
5 * 
2 
9-3 
61246.75 
} 
0.05 
385*4-1 
} 
4 7 
Middle of Kent 
5 1 
6 
49.6 
61248. 
} 
1.25 
38450.0 
} 
64. 1 
Greenwich Royal Obferv. 
5* 
28 
40 
612511 
} 
31 i 
38148.7 
} 
3 OI -3 
52 
0 
0 
61255. 
} 
3-9 1 
37712.3 
} 
436.4 
Gg 2 
Art, 
