&jj | ON THE MERIDIAN, | • £ 



and longitudes, of the principal places, both on the coasts and in the in- 

 terior. The original design has been vastly enlarged , and, in addition 

 to the triangles carried across the Peninsula, between the latitudes of 

 twelve and fourteen degrees, another series has been extended from 

 Tranquebar and J^Tegapatam, entirely across to Paniany and Calicut ; and 

 to render the skeleton complete, a meridional series has been carried 

 down the middle of the Peninsula, terminating at the sea near Cape 

 Comorin, from which have been extended other serieses, to the east and 

 west, entirely along both the coasts. From the above mentioned rneri«* 

 dional series, I have- deduced an afc of nearly six degrees in amplitude, 

 The members of the Szvedish academy have likewise been performing 

 a similar work ; but the sole intention of that was, the measurement of 

 a degree at the polar circle, as a test to the one executed by Maupertuzs 

 and his associates. These various performances have afforded the learn- 

 ed world the most extensive and the most accurate data hitherto obtained, 

 for determining a question of great importance .in physical astronomy, 

 viz. the dimensions and figure of the earth. This circumstance being in- 

 volved in many abstruse speculations, relating to the precession of the 

 equinoxes, the" nutation of the earth's axis, the parallaxes of the 'moon, 

 &c. &c. it has been found expedient, in order to make the theory agree 

 with the observations of astronomers, to adopt a figure whose elliptieity 

 was from ^to~», in place of — given by Sir I. Newton; and various 

 experiments, with pendulums in different latitudes, seemed to justify the 

 measure. It will appear in the sequel of this memoir, how far the recent 

 measurements may be relied on in computing according to the elliptick 

 theory; and certainly, from the great length of the arcs and their re- 

 moteness from each other, more reliance may be placed in computation 



