6 Mr Basset, On the Potentials of the surfaces formed by [Oct. 25, 
since QP’ —- QP, = VW’ -1)*; 
_ ao (y—1) rt 
PAP. () ie pe . 
If we put a=csech’}y, b=ccosech’dn, 
the equation of the meridian curve may be written 
r—a—b—(a—b)—=0, 
from which we easily obtain 
taEle E re Re 
7h 
mate {1 eo : 
T Cis 
Therefore 
ie 64c0%p 2+my— pw 
aR EG ote) 
m= 94°R (LH (8§=2 — po) 
e = 1! Wt) 
2+ py — we 
DA,P,, (uw) = 64arec (y?—1) . i 
? 
Let uU= le a : 
(w+) 
du yw — Qpy—3 
dy = (w+y)i 
2+PY—E OY 1 _2du 
(ery) SB8(ut+y)? 3(ut+y) 3dy 
= $20 (—)" (2n +1) fh yQ," (+ w+ 2-1) Q,(Y} Pi), 
where the accents denote differentiation ; 
A,="¥ra0(9" —1)(—Y*n +1) 2Q." (7) +08 +n=D QC) 
7. Similarly if R, R’ be the component attractions perpen- 
dicular to the axis, we must assume 
R =232 BQ.) Pee) P20) 
R=" 35 BP2(y) Q20) Pu) 
* Quarterly Journal, Vol. xix. p. 352. 
