T20 Gen. Roy’s Account of 
Settlor* Fourth . 
Calculation of the feries of triangles extending from Wind- 
for to Dunkirk, whereby the geodetical diftance between the 
meridians of the Royal Obfervatories of Greenwich and Paris 
is determined. Reference to be had to Plate IX. 
Settlor Fifth. 
'On the difference between horizontal angles on a fphere and 
fpheroid. Plate X. 
Settlor Sixth . 
Manner of determining the latitudes of the Rations. Ap- 
plication of the pole ftar obfervations to computations on dif- 
ferent fpheres, and alio on M. Bougurr’s fpheroid, for the 
determination of the difference of longitude. Ultimate refult 
of the trigonometrical operation, whereby the difference of the 
meridians of the Royal Obfervatories of Greenwich and Paris 
Is determined. Plate X. 
Settlor Seventh . 
An account of the obfervations made during the courfe of 
the trigonometrical operation for the determination of terreftriai 
refraction. Plato X. 
Settlor Eighth . 
Secondary triangles, fubdivided into two fets, for the im- 
provement of the maps of the country, and the plan of the 
City of London and its environs. Plate Xf. 
Conclufon , 
Containing Propofitions for extending trigonometrical opera- 
tions over Great Britain. 
SEC- 
i 
