zco 
Gen . Roy's Account of 
But if the fpheroid is known, the latit ice of a given point 
(v) in a great circle -perpendicular to ? ?e meridian, mav be 
found nearly from what has been deliver’d above. Thus, as 
rad. : cofine BP :: cofine Hv : cofine or an arc (FA' lei s than 
Yv, the co-latitude of v. 'Now, with the latitude (tuppofe of 
the point A) thus found, and the given latitude of B, find GS 
(fig. 2.) which will be very nearly equal to the arc Av, and 
the value of this, as an arc of the meridian, being added to 
PA, will give Pv 7 the co-latitude of v. 
SECTION SIXTH. 
* , * 1 
Manner of determining the latitudes of the fations . Application 
of the pole far obfervations to computations on different fpheres y 
and alfo on M. Bouguer’s fpheroid , for the determination of 
the differences of longitude . Ultimate refult of the trigonome- 
trical operation , whereby the difference of the meridians oj the 
Royal Obfervatories of Greenwich and Paris is determined* 
Plate X 
Article I. Preamble , foewing the general principles adopted 
for fettling the latitudes of the fations . 
In the Paper of 178*7, fo often quoted, and which was in- 
tended only as a iketch of the mode then propofed to be fol- 
lowed in conducting the recent trigonometrical operation, we 
had occafion to fihew, that the meafured arc of the meridian 
between the point M near Dunkirk, and Perpignan fituated at 
the 
