DEGREE. 
ft Cor. 1226.5 - = AA’ 
2d Cor, 26.89 _ ; 
3d Cor. 0.06 ¢ eee 
1253.45 2 20 53”.45 
Ufe of the Formula. 
— 3 R"” 
RS =e) eee 
ae 
e the refult. To the ne or the number of feet iu 
R ~ 
Add. conftant. log. eu - = 7.9941110 
Which gives Part I. = 12267.47 = 3.08865g0 
To double the log. x . = 0.1890960 
Add. contt. leg. - ea 8.9 653023 
Which gives Part II. = + 0.032 = 8.5049883 
Tf A’ is fouth, Part IT. is additive. 
A’ is pally Part IT. is ay aval 
n this c AA’ = 1226.47 + ole 
os = 
found cae in the laft cael This ae “th ak 
founded on a complex formula, is very ealy and convenient 
an praGice. The content mene is thus f a pa 
Log. 2 - ere 
= 77792374 
t—e 
R" . - - = 5.3'44251 
aa ny - - = 2.07868 £0 
o.-log = 2.6796860 
i= 5S 28! 40” = Sin.2/ = 9.9888016 
8.3 ee 
If the ‘adios of curvature be required toanarc making an 
angle V’ with the meridian, it’may be found thus : 
r+ 
n—r 
Rad. of curv. R = == — — cof. 2 V’, r being 
the rad. of curvature to the meridian, and nx the normal ; 
or, more exactly, 
r+a 
™m ee er 
2 
+ “cof. 2 V’ 
R= 
(7 + 2)° 
V' being the angle “ = required’: arc makes with the 
a as aa to the me 
the ufe of abe Paul, it tthowld be obferved, Mae in 
e modified, 1 each adapt 0 our 
For ¥ we have feen in the 
as given in lincar meafure, to reffion in terms of .the 
arc, it 1s ccna! to know eel aN radius of curvature 
1ft Cor, = 1223".64 _ 
2d Cor + rit = 
3d Cor. = 26.89 
4th Cor « 0.06 A’BY 
£259.46 20’ 937.46 
to which each Apart arc fhould be adapted. Upo 
{uppofition then of th eing of fome eeu figure, 
or that certain ee. in the dex fity of its ftrata pro» 
duce the fame effect, by the defleCtion of the plumb-line, from 
It is upon 
this ofculatory otiptoid that our eleuneas mutt be made, 
if we with to determine the true latitudes and longitudes of 
erste as be mott probably agree with accurate aftronomical 
obferva 
and Dunnofe, when we with to confider the meridian as meae 
{ured in England as a continuation of that meafured in 
France. In fecondary furveys, where the triangles are {mall, 
much of the labour of the preceding calculations may be 
oo by rejeGting the terms of the formule that involve 
*, and thus reducing the whole to {pherical computation; 
nor will it often be found neceflary to calculate the fpheri- 
cal excefs, particularly if attention be paid to Le Gendre’s 
theorem. And indeed the knowledge of the {pherical excefs 
might be always difpenfed with, if we had only to calculate 
the triangles of the ftations: but the cafe is different with the 
triangles which are decompofe the meridian line which 
paffes through them. In thefe partial anes one fide and 
ected. 
The computed roland hte Sl aed will be but little 
affeCted by the omiffion; b corretion fhould be attended 
to, when ee aiference bigcn the parallels is required 
with great ex 
ut it is ery “doubtful if any one ne hypothefis can be ex 
tended to a confiderable diftan V4 from the place-of actual 
obfervation. In example 1V. it may he rae what man 
ner Pe longitude of] Dunnofe was tnd pdletively to Beachy- 
y azimuthal obfervations at each ftation; and the 
puted on 
bs m example and x. re Xt great triangle 
w ae ard, it appears highly probate Gat the value of the de- 
gree on the perpendicular fuddenly diminifhes, ‘one _ the 
as have heen oh 
ferved in proceeding to the north. From all thefe confideras 
tions it follows, that the latitudes and longitudes of places, as 
sale to certaiu aitronomical pofitiors, can no longer be 
r 
onfidered as accurate er to defignate the relative 
fisaton of places on the earth think therefore that it 
db 
advifable, in geographical fore, of large extent, 
oe the relative latitudes and longitudes to fome iba 
t fhould be calculated b ae se fo ormulz or ot 
eal metheds, and that thefe fhou'd be conte a8 
3 mean 
