Ao. VIII. 



limrrirfTiTMiinrnjniBirfiTirni'w 



OF THE FIGURE OF THE EARTH, 



BY COL. TARED MANSFIELD, 



SURVEYOR-GENERAL OF THE UNITED STATE'S^ 



THE celebrated question concerning the true ngar'e 

 of the earth, so much agitated by rival philoso^ 

 phers of the last century, is one of the many in astrono- 

 my and physics, the solution of \¥hich is almost wholly 

 dependent on the mathematics. It is true indeed, that 

 physical considerations of the nature of gravity, imd the 

 rotary motion of the earth, first suggested to Newtoi^ 

 the idea that its figure must necessaiiiy diHer from that 

 of a perfect sphere or globe. This sagacious philoso- 

 pher and mathematician was likewise enabled, by the 

 use of his own sublime geometry, to determine a prior't, 

 whatever is required in thi^ problem, with a wonderful- 

 degree of precision. But the physicd principles ci 

 Ne^vton had not yet been verified by a sui?-cient number 

 of experiments and observations ; and the method af In* 

 ductton on which they were founded, must ever be infe- 

 rior in evidence, to the pure results of the mathematics* 

 In order, therefore, to a complete and satisfactory so« 

 hition of this problem, as well as for an investigation of 

 the principles aiid conclusions of Ncv/lon, it was neces- 

 sary to have recourse to an actual mensuration of the 

 earth, both in respect to magnitude and figure. Th^ 



