I0o Gen. Roy’s Account of 
hole with the axis of vifion of the telefcope was tried, and 
found to have ftiffered no alteration. 
In the VUIth triangle, the angle at Greenwich, between 
Severndroog Caftle on Shooter’s Hill and the ftation on Norwood 
heights* hath been fhewn to be m° 5 6 ; 50". By feveral obfer- 
vations on different parts of the circle, Norwood ftation was 
found to be weftward from the meridian 38° f which of 
courfe leaves for the angle that Severndroog Caftle is eafhvard 
from it 73° 49 / 34 x/ ; and either of thefe two angles is fup- 
pofed to be within a very fmall fradtion of a fecond of the 
truth. 
Now, with the fides and angles of the feries of triangles 
already known, and the angle 38° f 1 W' now given, which 
Norwood makes with the meridian of Greenwich towards the 
weft, it will befufficiently obvious to thole who are in the leaft 
acquainted with plane trigonometry, that the diftances of that or 
of any other ftation of the feries, from the meridian of Green- 
wich and from its perpendicular, are eafily obtained. Never- 
thelefs, that thofe who are but little converfant with matters 
of this fort may themfelves be able to examine the computa- 
tions whereby the columns towards the left-hand of the an- 
nexed table have been fupplied, we fhall give one example, 
which will ferve for the whole. 
Suppofe (Plate X. fig. 1.) GM to reprefent the meridian of the 
trail fit- room at Greenwich ; GW the perpendicular to that 
meridian produced indefinitely towards the weft ; N the ftation 
at Norwood, and H that at Hundred Acres, whofe diftances 
are required, that is to fay, weftward from the meridian, and 
fouthward from the perpendicular : then through the ftations 
N and H, let dotted lines be drawn parallel to the meridian 
and perpendicular refpedtively, whereby four parallelograms 
will 
