20 a Gen. Hoy’s Account of 
the latitude of 51 3 f. Again, if the total length of one- 
fourth part of the fpheroidical meridian of the earth, between 
the equator and the pole, 5478094.4 fathoms be divided by 90* 
(Fig. de la Terre de Bouguer, p. 310. and 311.), we fhall 
have 60867.72 fathoms for the mean degree of the meridian, 
which in the fame table will be feen not to differ fenfrbly from 
that anfwering to the latitude of Greenwich ; in or near which 
parallel the curves of fuch a fphere and M. Bouguer’s 
fpheroid interfeft each other, as will be readily conceived by 
referring to and confidering the rcprefentation of them, in 
Plate X. fig. 3. 
Art. II. Of the pole-far obfervatlons in general. 
It became neceffary, in the preceding article, to point out 
in what manner the latitudes of our ftations have been de- 
duced from their relative fituation with regard to Greenwich ; 
becaufe the method adhered to of fettling the differences of 
longitude by the obfervations of the pole-ftar, which could 
rarely be made except on one fide, that is to fay, at night, 
when the ftar was eaftward from the pole, implied as a matter 
of courfe, that the latitude of the ftation fhould be accurately 
known, for the computation of the ftar’s azimuth. With the 
declination of the ftar, fettled to fo great a nicety as it has 
been by the Aftronomer Royal, and the latitude of the place 
given, a fingle azimuth was fufficient for obtaining imme- 
diately the true direction of the meridian. Much time would 
have been ufeleflly loft in attempting to get obfervations of 
the ftar in day-light when on the weft fide of the pole, whereby 
the double azimuth would have been obtained ; and in that 
cafe the bifedlion of the angle would have given the true me- 
ridian of the place, without the knowledge of its latitude. 
For 
