SO:lf ' - ACCOUNT OF EXPERIMENTS ' 



Example s. 



The length /, at the equator, being thus founds we have, for the length 



at the pole ■' '' , i^-- ■ • ■■ 



S*/ = 23.90428^ 'L = 39.12800 ■ 



(x--/)= 0.1 1107 C I ^ 39.0169 3 ;.;;;;;, 



-v.]£. S^/ + ('L — = 24.01535) 'L"~^ = 0.11107 • 



and 24.01535 -^ 0.6126^44 ^ 39.19B218 =^ L the length of the pendulum 

 ^t the pole. 



.[-•-, 



j^^= 



The tables at the end will shew the results of the various combi- 

 nations of experiments, under eight different parallels of latitude ; among 

 which, however, I have omitted computing for the length at the pole by 

 the four lowest latitudes combined ; being too near each other, and too 

 remote from the pole, to obtain results at all satisfactory, I did not, how» 

 ever, think it expedient to omit combining the results of the four lower 

 latitudes, for obtaining the length at the equator; for the reason assigned 

 lower down, and also, because Manilla and Porto Bello are sufficiently 

 near to that circle J not to fear any material error in the result. This will 

 appear from the near coincidence of the lengths thus computed with that 

 resulting from Mr. Bouguer's experiment at the equator^ 



3^" A circumstance occurs in these tables, which seems to claim our 

 attention; I mean the increase zt the. equator, and decrease sit the pole, as 

 the places referred to (combined with high northern latitudes) become 

 more distant from the equator ; and on the contrary, the decrease of the 

 lengths at the equator, as the places referred to are higher than those 

 with which they are combined, 



37. Although these increments do not seem to follow any regular 

 law, yet they evidently indicate a deviation, not to be ascribed to chance 



