[phi] = m ch([eta] - [alpha])cos [xi]
= -Uc ch([eta] - [alpha])sh [eta] cos [xi]/sh([eta] - [alpha]) (12)
over the cylinder [eta], and as in (12) § 29,
[phi]1 = -Ux = -Uc ch [eta] cos [xi], (13)
for liquid filling the cylinder; and
[phi] th [eta]
------ = --------------------, (14)
[phi]1 th ([eta] - [alpha])
over the surface of [eta]; so that parallel to Ox, the effective
inertia of the cylinder [eta], displacing M´ liquid, is increased by
M´th [eta]/th([eta]- [alpha]), reducing when [alpha] = [oo] to M´th
[eta] = M´(b/a).
Similarly, parallel to Oy, the increase of effective inertia is M´/th
[eta] th([eta] - [alpha]), reducing to M´/th [eta] = M´(a/b), when
[alpha] = [oo], and the liquid extends to infinity.