21 t 
the Trigonometrical Operation . 
HTF, or that between the lamp at H and the white lights 
repeatedly fired at F, was twice obferved 22' 48" ; therefore 
120 0 24 ' 5 7". 8 7 + 22' 48"= 120 0 47 / 45.87 is the angle PTF, 
that the Ration on Fairlight Down makes with the meridian of 
Folkftone Turnpike. 
Now, rT being equal to 45827.88 fathoms, and RF = 
2 '’884.68 fathoms, if we take 61253! fathoms = 1°, we fhall 
have Gr= 22871 fathoms = 22' 24 // . 18 ; GR = 36436.1 fa* 
thorns = 35' 41 '".42} rT = 44' 53^-4 ; and RF = 23' zf'-JS % 
therefore PR, the co-latitude of R, will be 39 0 7' and 
that of r or P r will be 38’ 53' 44". 18. Hence, in the right- 
angled fpherical triangle PRF, we fhall have the angle RPF = 
nj' 4". 901, and PF = 39° 7' y^.294- Further, the triangle 
PrT gives the angle rPT=T 11' 29". 143, and PT = 
38° 54' j^.98. Now, i° 1 1' 29 // .i43-37 / 4 ,/ .90i = 34 / 
24 /, .242=the angle FPT. This laft angle, with the twct 
containing fides PT and PF, give the angle PTF= 120° 47' 
44 // < 75, the fame as it was actually obferved very nearly. And 
hence we have another ftrong proof, that on this part of our 
earth the degree of a great circle , perpendicular to the meridian , 
cannot differ much in length from 61253! fathoms, whatever may 
he its real figure, ‘which cannot be determined until thefe obferva- 
tions fhall have been compared with others that may hereafter be 
made in the fame way , and with equal care , in latitudes remote 
1 
from each other . 
38° 54' 1 4". 7 : rad. :: fine i° 49' l8".03 : fine 2° 54' 5". I a the tar’s azimuth. 
Twice this angle, or 5 0 48' io' / . 24 > a S rees ver y near ty w * t ^ 1 the double azimuth 
5 0 48' Io"|, found by the obfervations on the yth and 8th of September. This 
near agreement, at the fame time that it ferves to fhew the accuracy of thefe. obfer* 
vations in particular, and the goodnefs of the mode that was adopted in general, 
ferves alfo to prove, that Dr. Maskelyne has fettled the declination of the pole® 
tar to great precifion. A 
t? p. 'j Art# 
E e 2 
