  The photoeffect, (vacuum analogue of the photoelectric effect,) is used to
study the structure of the physical vacuum, the outcome of which is the basis
for an hypothesis on the nature of gravitation and inertia. The source of
gravitation is the vacuum which has a weak massless elementary electrical
dipole (+/-) charge. Inertia is the result of the elastic force of the vacuum
in opposition to the accelerated motion of material objects. The vacuum is seen
as the source of attraction for all bodies according to the law of induction.
