  The trace identity associated with the scale transformation $x^\mu\tox'{}^\mu
= e^{-\rho}x^\mu$ on the Lagrangian density for the noninteracting
electromagnetic field in the covariant gauge is shown to be violated on a
single plate on which the Dirichlet boundary condition $A^\mu(t,x^1,x^2,x^3=-a)
= 0$ is imposed.It is however respected in free space,i.e. in the absence of
the plate; these results reinforce our assertions in an earlier paper where the
same exercise was carried out using the Lagrangian density for the
free,massive,real scalar field in 2 + 1 dimensions.
