[en] We consider the distributions of the scalar gravitational potential of Coriolis forces in different parts of the shoulder of a rotating equal-arms Michelson interferometer. It results in a view of the very small difference between the phases of light in the shoulders of the Michelson interferometer, in comparison with the phase difference due to the quadratic Sagnac effect. It has been shown that there is an effect, discussed earlier by P Maraner, which is a higher approximation to quadratic Sagnac effect. (letters to the editors)