Ih Solutions of three Chorographic Problems^ ly 
a Mcmheioftk Philofophical Society o/Oxford. 
TH E three following Problems may occur at Sea,' 
in finding the diftance and pofition of l{pcks, 
Sands y &c, from the fhore,- or in furveying the Sea 
Coaft; when only twa objcds whofe diftance from 
each other is known, can be feen at pne ftation: but 
efpecially they may be ufeful to one, that would make 
a Map of a Countrey by a Series of Triangles deriv- 
ed from one or more meafured Bafes,- which is the 
moft exad: way of finding the bearing and diftance 
of places from each other, and thence their true Lon- 
gitude and Latitude and may confequently occur to 
one that would in that manner meafure a Degree on 
the Earth. 
The Firjl Problem /Fig. r. and 2.j 
There are two objeds B and C, whofe diftance B C 
is known, and there are two ftations at ^ & E, 
where the objects 5, C being vifible, &the ftations one 
from another, the Angles 5 ^C, BAE.JEB, ABC, 
are known by Obfervation, which may be made with 
an ordinary Surveying Semicircle, or Groflaff, or if 
the objects be beyond the view of the naked Ey, 
with a TelefcQpic ^iuadrant) to find the diftances of 
lines AB, AC, AE, EC. 
Conjtru^ion. 
In each of the triangles BAE, CAE, two angles at 
A, E, being known, the third is alfo known : then take 
any line cti at pleaiure, on which conftitutc the tri- 
angles l3ct£, ct.^y refpedively equiangular to the trian- 
gles B^S, ARC s join (iy. Then upon Z)C conftitntc 
the triangles equiangular to the correfpon- 
P p p dent 
