2 7 o DEVELOPMENT, &fc. 



per upon that fubjecT:, which we have already quoted : his fo- 

 lution, however, is obtained without any reference to the ellipfe. 

 I might now ihew the application of the different methods 

 here inveftigated, by calculating the values of A and B in fome 

 particular cafe, as, for example, in the cafe of Venus and the 

 Earth ; but as thefe methods have been fufficiently detailed, fo 

 as to be eafily underftood by any perfon fkilled in arithmetical 

 calculation, I mall conclude this paper, and give, in the form of 

 an Appendix, the investigation of a new formula for the recti- 

 fication of any elliptic arch whatever ; but from which, in the 

 particular cafe of that arch becoming a quadrant, we imme- 

 diately derive the third and laft formula mentioned in this pa- 

 per, for finding the femi-perimeter of. an ellipfe. 



JPPEN- 



