2 g Gen. Roy’s Account of 
the diftance of fifty or fifty-two miles. This laft commands a 
moft extenfive profpeft over the plain of the Severn and the 
Welch mountains to a great diftance beyond it. Pen-y-l oel 
Hill, called alfo the Sugar-loaf of Abergavenny, in Mon- 
mouthlhire, would become the third Ration to the weftward ; 
and two, or at moft three, Rations more would reach St. Da- 
vid’s Head, oppofite to Wexford in Ireland. 
But let us fuppofe, in the firft place, the feries of triangles 
to be extended only to the third ftation, in all which ipace it 
would be wholly unneceffary to obferve any latitudes ; by the 
pole-ftar obfervations, repeated a fufficient number of times on 
both fides of the pole, at each of the ftations, the length of 
the degree of a great circle, perpendicular to the meridian, 
and confequently the differences of longitude, would thereby be 
obtained to the utmoft precifion. A determination of this fort 
would abfolutely be conclufive, with regard to the length of the 
vertical and radius of the parallel in the latitudes of the refpec- 
tive ftations, afcertainable by their diftances from the perpen- 
dicular to the meridian of Greenwich. 
The fecond part of the operation would be that of carrying 
a feries of triangles fouthward from Pen y-Voei Hill, in the 
dire&ion of its meridian to the Britifh Channel; and after- 
wards extending thefe triangles in the ufual manner over the 
whole fouth part of the illand between Kent and the Land s- 
End. 
If, b elides the zenith feclor, another circular inftrument was 
provided, and fodne additional annual expence allowed, in order 
to accomplilh more fpecdily lo great and uleful a work, at the 
fame time that the operations to the fouthward were carrying 
on, the feries of triangles, in the direction of the meridian of 
Pen-y-Vocl Hill , fhouid be continued to the northward through- 
