Abstract
The conclusion of this work is really very small. It is that
the five dimensional integral for the imaginary part of the
Delbruck scattering amplitude allows two further integrations to
be carried out analytically, before it is absolutely necessary to
resort to machine computation. Whether it would be quicker to
carry out the work fully, i.e. obtain a three dimensional integral
representation for the imaginary part, and then integrate
numerically, or to find another computing programme, which allows
one to integrate the five dimensional integral at higher energies
is another question.
