My 
the equations for the second approximation (satisfied by the 
coefficients of @& ) have solutions which yield periodic waves 
of permanent form, similar to those of Korteweg and DeVries, 
and also solitary waves, similar to those of Rayleigh and 
Boussinesq . 
The solution of permanent form, as given by the first and 
second approximations, for the irrotational, two-dimensional 
motion of an incompressible, inviscid fluid of, mean depth h 
over a horizontal bottom is developed. 
