MR. HENNESSY’S RESEARCHES IN TERRESTRIAL PHYSICS. 
531 
By following a similar process we obtain 
A=|js- 
■ M 
, B=. S 
M'^'l 
and consequently 
2 C-A-B _^ 
C — 
neglecting quantities of the second order. 
On substituting for ^2 its value (art. 9.), 
%(«')— %(«i)=^^{[ 2 w 2 +(w 2 — 6 )^ 2 ] sin ^ 2 — [ 2 afwH-(aX- 6 )^*] sina,W 2 } ; 
and similarly, on substituting for § its value in 
6 ) 9 ,] ; 
but by articles 8. and 9, 
__ (g.) _ 
C,=4 
sin 
, .sina.ji, . / N 
f2— fe) sinn.’ M_4 t(^2)92 
(^> 2 ) being the value of §2 cit the shell’s outer surface. Hence, finally, 
1 fr. 2 I / 2 ~\knl^\na^n^'\ 
+ 2 aH(«;-;i)?, H— 
L \ Ml/ J rii sii 
sin M 2 
But we have, by article 9, 
and on comparing equations (20.) and (23.), 
2e + M^— X 
^=- 
(34.) 
hence if we make 
2 C-A-B 
-=P 
we shall obtain 
or 
making for brevity 
|2a?+(^a?— ^j93-|j[2a?+(«?-^)9i]}sin«iW2=Q, 
^^'(^■~f;)“®(^“j2)^3}sina,W2=Q, (35.) 
W 2 (36.) 
6> 
\ 2 
2e + OT — X q 
(' 
1^2 3* 
p' 
But the value of p' is given from the phenomena of the precession of the equinoxes 
and the nutation of the earth’s axis, and that of \ may be obtained from experiments 
made with the pendulum on the earth’s surface, or from the inequalities in the moon’s 
motion in longitude and latitude depending upon the form and internal constitution 
