Hans Witte

“ Michelson experiment of 1904 and the Sagnac experiment of 1913 have the fundamental idea in common, to split a light ray in a rotating circle, and to circulate one ray counter-clockwise, and the other one clockwise. The difference consists mainly in the fact, that Sagnac uses a circle rotating relative to Earth, while Michelson wanted to use a circle at rest relative to Earth, thus he wanted to use the self-rotation of Earth. ”

“ If one considers the rotating system from the view of the rest-system, then the light ray which is following the same direction of the rotation, experiences a path-elongation corresponding to the factor , yet also a velocity increase corresponding to the same factor , which is canceling each other; the same arises at the oppositely moving ray ; there, is the orbit velocity of () , is the speed of light. ”