A method of solving the canonical Hamilton equations, based on a searc
h for invariant manifolds, which are uniquely projected onto position
space, is proposed. These manifolds are specified by covector fields,
which satisfy a system of first-order partial differential equations,
similar in their properties to Lamb's equations in the dynamics of an
ideal fluid. If the complete integral of Lamb's equations is known, th
en, with certain additional assumptions, one can integrate the initial
Hamilton equations explicitly. This method reduces to the well-known
Hamilton-Jacobi method for gradient fields. Some new conditions for Ha
milton's equations to be accurately integrable are indicated. The gene
ral results are applied to the problem of the motion of a variable bod
y. (C) 1997 Elsevier Science Ltd.