In the general motion again of the liquid filling a case, when a = b, Ω3 may be replaced by zero, and the equations, hydrodynamical and dynamical, reduce to

= − 2c2Ω2 ζ, = 2a2Ω1 ζ, = 2c2(Ω2 ξ − Ω2 η)
dt a2 + c2dt a2 + c2dt a2 + c2

(18)

dΩ1= Ω2 ζ + a2 + c2ηζ, dΩ2= −Ω1 ζ − a2 + c2ξζ;
dt a2 − c2dt a2 − c2

(19)

of which three integrals are

ξ2 + η2 = L − a2ζ2,
c2

(20)

Ω12 + Ω22 = M + (a2 + c2)2ζ2,
2c2 (a2 − c2)

(21)