386 Proceedings of the Royal Institution^ 



similar cases, to obtain a remarkable approximation to its solution. 

 He estimated the compression at ^^, or that the polar axis was 

 shorter than the equatorial diameter, by that amount. Cassini, from 

 the measurement of an arc of the meridian extending across France, 

 had come to the opposite conclusion, that the earth was elongated 

 towards the poles, and hence a warm controversy arose among seveta^ 

 of the distinguished philosophers of that age. ,..|^ 



To decide this question by experiment became an object of the 

 deepest interest to the scientific world ; for not only was it important 

 and curious of itself, but Newton had further shewn, that to this 

 aberration from the spherical figure, were due the phenomena of the 

 precession of equinoxes, and the nutation of the earth's axis. It was 

 a task, however, beyond individual means, and which governments 

 alone could execute. By her efforts in this respect, France stands 

 pre-eminently distinguished; she sent her ablest academicians to 

 Lapland and Peru ; provided them with abundant means, and fur- 

 nished them with the best instruments that could be procured. Even 

 Italy contributed her share. But England, whom the fame of Newton 

 and the interests of navigation, ought to have excited to honourable 

 rivalry, remained insensible and inactive. 



Though the results of these measurements verified the general fact 

 of compression, yet many singular discrepancies appeared, and the 

 problem was found to be by no means of such easy solution as was 

 at first supposed. These discrepancies are now known to proceed 

 from partial irregularities in the surface of the earth, and also from 

 errors committed in the measurements themselves ; but they demon- 

 strate the necessity of multiplying those measurements under different 

 meridians, and of collecting more unexceptionable data before the 

 problem can be satisfactorily solved. 



Deduced as the figure of the earth is at present from the combir 

 nation of measurements of very unequal value, — ^the more recent exe? 

 buted with every refinement of art and science, — the earlier performed 

 with very inferior means, — with ruder instruments, and consequently 

 with more vague notions of accuracy on the part of the observers, 

 than would now be admitted, it cannot be wondered at that ano- 

 malies still exisV whiek wit^ mc»re mmi&9^iAQuM^ dfttA would cease 

 to appear. ,^&:^ii hziibm^^ &io ii^i^d a;:^i i^tlnfinnsisii . . : 



