III! iiimiii Mill 



112 • 



MEASUREMENT OF AN ARC 



(3) 



X rr 604S1.27 «,, .,, o. .....,_,./..'.. 11 34 44.^ 



(4) 



X = 60486.09 ,,.....-... »o,.... 12 34 44 



(5) 



X := 6Q491.3 ..c .o. ....,,.,„. oo,. .,,o^..' 13 34 44 



(6) 



X rr 60495.89 e. o, ........... 14 34 44 



(7) 



X — 605,02.86 ...0. ..................................... .a,..o,.. 15 34 44 



(8) 



X ::r G0509.2i » , .,.,. .-....., .., 16 34 44- 



CP) . -' .. 



X ~ 60516,91 ....,,= ......., .o..... .,. o.,= , = ..,.,,.,,., 17 34 44 



Thefe refults are the fame very nearly as in the above table ist. and 



?%, Sin. (59 9 285) is the fame as d in the former eafe. 



J 8. \¥ith refpe6i; to the compreffioij^ that nothing ma)f be left un- 

 done tQgwe full and eatirefatislaction on that fubjeS:, 1 fliall here 

 add an invefcigation fimilar to that given by ProfeiTor Play fair in the 

 ^ih Y oh o^ ihQ Edinburgh Phi lofophical TranfO'^i^'ns^ where in place o£; 

 ufing the meyfurrs ot (ingle degrees dur to particular latitudes, twa 

 meafured arcs.. of large amplitudes, are made ufe of, the latitudes of 

 whofe extremities an- determined with great accuracy. 



Let A, B, B, £, be a meridian of the earth, where ^ is at the 

 equator, and Z) at the pole. Suppofe F to be any point on that: 

 mesid^aii, and F H the radius of curvature of theellipre at the faid.; 

 point. Put A C = a,.. 



D C ^=b, C being the, 

 ceii ter of the ellipfe, 

 and let A be equal 

 the and e A K F, the.- 

 Jatiiude of F, or let it 

 be the me a fur e of the 

 arc of latitude to rad, 

 a i that is,, the meafure^- 

 of the angle A K F In 

 psvts of the lad. j.»-=. 

 M-0 F be an mdcli«. 



D 



B 



Ik^ 



