(8)

the intrinsic equation, the other free surface A′P′J′ being given by

eπ2/c = cos2 nα sin2 nθ,
sin2 nα − sin2 nθ

(9)

Putting n = 1 gives the case of a stream of finite breadth disturbed by a transverse plane, a particular case of Fig. 7.

When a = b, α = 0, and the stream is very broad compared with the wedge or lamina; so, putting w = w′(a − b)/a in the penultimate case, and

u = ae−w ≈ a − (a − b)w′,

(10)

ch nΩ = √ w′ + 1, sh nΩ = √ 1,
w′ √ w′

(11)