  This paper inspects more closely the problem of the momentum and energy of a
bound (non-radiating) electromagnetic (EM) field. It has been shown that for an
isolated system of non-relativistic mechanically free charged particles a
transformation of mechanical to EM momentum and vice versa occurs in accordance
with the requirement PG=const, where PG is the canonical momentum. If such a
system contains bound charges, fixed on insulators then, according to the
assumption of a number of authors, a so-called "hidden" momentum can contribute
into the total momentum of the system. The problem of "hidden momentum" (pro
and contra) is also examined in the paper, as well as the law of conservation
of total energy for different static configurations of the system "magnetic
dipole plus charged particle". Analyzing two expressions for electromagnetic
momentum of a bound EM field, qA and the Poynting expression, we emphasize that
they coincide with each other for quasi-static configurations, but give a
discrepancy for rapid dynamical processes. We conclude that neither the first,
nor the second expressions provide a continuous implementation of the momentum
conservation law. Finally, we consider the energy flux in a bound EM field,
using the Umov vector. It has been shown that Umov vector can be directly
derived from Maxwell equations. A new form of the momentum-energy tensor, which
explicitly unites the mechanical and EM masses, has been proposed.
