Trigonometrical Survey . 
537 
ART. VII. 
The longitudes and latitudes of the stations have been 
computed spherically, in which we have taken the degrees 
upon the meridian, and of the great circle perpendicular to it, 
from the following table. 
Degrees on the 
merid. perp. 
v, , „ Fath. Fath. Fathoms, 
f 50 41 60851 61 182 'l Semi-transverse of 
Lat.J 51 5 60859 61185 f this ellipsoid - 3491420 
1 51 28 40 60868 61188 J Semi-conjugate - 3468007 
Ratio of the axes 1 : 1,006751 
This ellipsoid is determined from the length of the degree 
obtained from the directions of the meridians at Beachy Head 
and Dunnose, and that upon the meridian in lat. 50° 41', as 
resulting from the application of the measured arc between 
Greenwich and Paris, to their difference in latitude. It is not 
however, to be understood, that by using it, we consider the 
earth to be this ellipsoid : we have adopted the hopothesis, 
because it is obvious some small increase northward must be 
made to the degree upon the meridian in 50° 41', in order to 
approximate to a correct scale for the computation of the lati- 
tudes. But it is evident, that any of the received hypotheses 
(supposing the length of the degree upon the meridian in 
50° 41' to be 60851 fathoms) would give the degrees suffi- 
ciently correct, since the principal stations, together with most 
of the objects fixed in this operation, are included between the 
parallels of 50° 37' and 51 0 28'. 
In obtaining the latitudes of those places which are referred 
to the meridian of Greenwich, it is easy to perceive, that little 
error is introduced by spherical computation, since the sphe- 
