  The paper aims to apply the complex octonion to explore the influence of the
energy gradient on the Eotvos experiment, impacting the gravitational mass in
the ultra-strong magnetic fields. Until now the Eotvos experiment has never
been validated under the ultra-strong magnetic field. It is aggravating the
existing serious qualms about the Eotvos experiment. According to the
electromagnetic and gravitational theory described with the complex octonions,
the ultra-strong magnetic field must result in a tiny variation of the
gravitational mass. The magnetic field with the gradient distribution will
generate the energy gradient. These influencing factors will exert an influence
on the state of equilibrium in the Eotvos experiment. That is, the
gravitational mass will depart from the inertial mass to a certain extent, in
the ultra-strong magnetic fields. Only under exceptional circumstances,
especially in the case of the weak field strength, the gravitational mass may
be equal to the inertial mass approximately. The paper appeals intensely to
validate the Eotvos experiment in the ultra-strong electromagnetic strengths.
It is predicted that the physical property of gravitational mass will be
distinct from that of inertial mass.
