[ 3 2 3 ] 
To find the Latitude of the Point N. 
£ Perfei Capella /3 Aurigae Caftor 
O / // Oil ! Oi l ! oil / 
True obferved zenith dill. "1 / 
reduced to I Jan. 1764 . ) 7 4 22 > 2 S 47 32,3 4 57 z6 >3 7 33 23,1 
Stars decl. by Dr. Bradley. 47 O 4^.0 45 43 S 3 >° 44 53 44 > 2 3 2 22 5 6 > 8 
■Latitude by the different ftars. 39 56 1.7,8 56 20,7 56 17,9 56 19,9 
20,7 
17,9 
*9>9 
1 8,2 
Means; 39 56 1 8, 9=the latitude of thepointN. 
Arch between N and A=: I 28 44>9 
38 27 34 — the latitude of the point Aj 
39 II 56 = the mean latitude* 
a Lyrae. 
0 / II 
1 21 44,2 
38 34 34’° 
56 18,2 
Cha. Mafon. 
Jere. Dixon. 
•r 
The Length of a Degree of Latitude in the Province of Maryland and 
Pennfylvania, deduced from the foregoing Operations 3 by the 
Aftronomer Royal. 
HH H E difference of latitude of the points N and A, or the amplitude of the celeftial 
arch, anfwering to the diftance between the parallels of latitude palling through 
N and A, has been found by the fe&or, page 306, to be i° 28' 45A0; The terreftrial 
meafure of the diftance of the faid parallels is next to be found. This is compofed of 
the fum of the lines N P, CD, D g, and AR, the laft mentioned line being the re- 
duction of A B to a meridian line palling through A : therefore B R exprefles a parallel 
of latitude palling through B. Let B / be an arch of a great circle drawn perpendicular 
to the meridian line, AR produced. The triangle BA/, on account of the fmallnefs 
of its Tides with refpeeft to the radius of the earth, and the fmallnefs of the angle BA/ 
— 3° 43^ 30" may be taken fora plane rectilinear triangle, in what follows, without 
any fenfible error, as will appear to any one who makes the trial. Therefore it will 
be, by proportion, as radius is to the cofine of the angle B A 43' 30" fo is 
A 6=434011,6 Englifli feet, to A/=433094,6 Englifh feet. But this is to be leflened 
by the fmall quantity R /, or the diftance of the parallel circle B R from the great circle 
T t 2 B /, 
