92 A NEW METHOD OF DETERMINING 
When we consider only terms of the first order with respect to the disturbing 
force, ¢ changes into 7, and we have 
rie Una es tf W, dt 
ae (27) 
J 
yo N—}h (=) dt 
where 
Wy = 27 — #1427 £2 cos +27 .n./ sino, (28) 
and p and are functions of +, being found from 
Mt +G = xy7—EASiINY 
p COS @ = A COS Y — A & 
psIN@® = a COs sin 7. 
Also in the last two terms of W,, . is put equal to unity. 
‘When terms of the order of the square and higher powers of the disturbing force 
are considered, ¢ cannot be changed into t. In this case let 
Nyt = MT + J + ndz. 
Likewise let 
M6 = MT + Jo + 206 
where 
no¢ is a function of 7 and t. 
According to Taylor’s theorem we have 
W = Wi+ 2 064 4S 80 + ote. 
the value of W, being given by (28). 
