s 58 Gen. Roy’s Account of 
Folkftone Turnpike . • weftward from the Pubiic-houfe. 
The Rations of the fecond fet, where the inftrument was 
elevated on buildings, are nine in number, viz. 
Hanger-hill Tower. 
Tran (it- room of Greenwich Royal Obfervatory. 
North-weft turret of Severndroog Caftie, on Shooter’s Hill. 
Swingfield Church Steeple. 
North turret of the Keep of Dover Caftie. 
Lydd Steeple. 
Tenterden Steeple. 
Goudhurft Steeple. 
Frant Steeple. 
SECTION FOURTH. 
i 
Calculation of the feries of triangles extending from Windfor to 
Dunkirk , whereby the geodetical difance between the meridians 
of the Royal Obfervatories of Greenwich and Paris is deter- 
mined. Reference to be had to Plate IX.. 
* 
' ‘ / 
Article I. Excefs of the angles of fpherical above thofe of 
plane Triangles. 
IF the earth, or any confiderable portion of Its furface, 
was a perfect plane, an inftrument, fuch as has been formerly 
defcribed, when applied on that furface, to determine by tri- 
gonometrical meafurement the extent of the plane part, would 
every where have its axis parallel to itfelf; and the lum of the 
three 
