  The paper discusses impact of the velocity curl on some conservation laws in
the gravitational field and electromagnetic field, by means of the
characteristics of quaternions. When the velocity curl can not be neglected, it
will cause the predictions to departure slightly from the conservation laws,
which include mass continuity equation, charge continuity equation, and
conservation of spin, etc. And the scalar potential of gravitational field has
an effect on the speed of light, the conservation of mass, and conservation of
charge, etc. The results explain how the velocity curl influences some
conservation laws in the gravitational field and electromagnetic field.
