i pS Gen , Roy’s Account of 
evident, that it will be augmented as the point obferved is 
below B. 
The latitudes of A and B being 49^ 4c/ and 50°, and their 
difference of longitude 3c/, BG will be nearly equal to AG, or 
3509769 fathoms, and GR being equal to 141.36 fathoms, 
and the angle GRB a right one, we have BG (3509769) : rad. 
:: GR (141.36) : fin. 8", the angle GBW, or T Bn. Now, 
fuppofing the point T to be a mile above the furface, this with 
the angle tzBT = 8 7 , will give T n equal to about three inches ; 
but T/z is in the plane of the meridian PBE, and confequentiy 
would be feen obliquely, if viewed from A, becaufe the angle 
ABT is about 135°, and therefore T n muft fubtend a very 
fmall angle at the diftance of 33 \ miles, which is nearly the 
diftance between A and B. 
From the determination of the horizontal angles that would 
be obferved at A and B (fig. 2.) on the fpheroid, if AP, BP, 
the co-latitudes of A and B are known, and the angles ABP, 
BAP, are given by obfervation, it follows, that the greater of 
thefe obferved angles muft be augmented, and the leffer dimi- 
nifhed, by the fame quantity of a degree, till the fum and dif- 
ference give the oppofite fides AP, BP, accurately by fpherical 
computation, and then the third angle, or difference of longi- 
tude, will be given : for the obferved angles at B and A being 
refpeftively 135 0 33" 17 A3 and 44° 3' 47 // .i, we have fine 
I 35 ° 33 ' I 7 - /, 3 ’+ ll/ 5 s "- 9 : fine AP :: fine 44 0 f 47"* - 
u / 58 /x .9 : fine BP accurately; but taking the angles that 
would be obferved, fine 135° 3 f 17A3 : fine AP :: fine 44 0 3 ' 
47 : fine of an arc greater than BP ; and fine 44 0 3 / 4y // .i 
: fine BP :: fine 135 0 33' if ^3 : fine of an arc lefs than AP; and 
this will fhew if the obferved angles are confiftent, as angles that 
