18 CURVE OF 



/ -,/ 



Therefore ^3/+ -7— 



my p 



= ; or taking 



V(wz* + mp2) , ^ {nx — mp) 



* • m WW 



ny4 2X 



the fluent, /^ 



V ( n z^ -j- 7;j^2 ) V ( n X — mp) 



ERRATA. 

 The reader is desired to correct the following faults which have 

 escaped notice in due time. 



Page 5, Fine 8, 2 should be in the denominator. 



6, — 1, n r should be n'r. 



1 6, — 8, n y^ should be w y' and w 2^2 should be na^ . 



