1888.] of Curves and of Surfaces. 241 
geben lade aun 
Go y, Cae 
O(€,) O(&) O(& 7) w 
By combining the equations 
COG Ones noe 
Oy 0z Oz dy — "Oa 
On OF Ones wee 
i ae Oz 0x Ox dz Oy? 
we obtain 
i et - a ag) + (ae) =" 1s oy ay St 
ie m (ae) G) sae “Ney 
Thus we have h,’= wv; and hae we should obtain h,’= vw and 
2 Pa 2), 2 PA - 
h, =wu. Combining these we have h,*h,’=h,’w"; and, consequently, 
we obtain the equations 
lel WHE 
= US w= ’ 
> P) 
h, h, h, 
10. We are now in a position to determine the value of q 
from the equation g.dp=dce . q, where 
_, a dg 
do=ig +i ee 
and dp =ide+jdy +kdz. 
If we write g=f+72l +ym+ kn, we have the equations 
l dg +m — a +n iy Idx + mdy + ndz, 
h, hh: . 
i = ar 2 ae mo = 2 = file + mdz = ndy, 
pels hein tnd mle 
3 
ley, Hee nhea 
