Hendrik Lorentz

“ Now we can assume at present, that electric and magnetic forces act by intervention of the aether. It is not unnatural to assume the same for molecular forces, but then it can make make a difference, whether the connecting line of two particles, which move together through the ether, is moving parallel to the direction of motion or perpendicular to it. One can easily see, that an effect of order is not expected, but an effect of order is not excluded and that is exactly what we need.
Since we know nothing about the nature of molecular forces, it is impossible to verify the hypothesis. ”

“ We want to transfer this to the molecular forces, and imagine a solid body as a system of material points, in equilibrium by the influence of their mutual attractions and repulsions. The system shall be a body moving through the aether. The forces acting on its material points eliminate each other. ”

“ In this way it can be seen, that when is the state of equilibrium of the body during the displacement in the aether, is the state of equilibrium when the displacement doesn't exist. One therefore comes exactly to the influence of motion on the dimensions, which was shown before to be necessary to explain Michelson's experiment.
Of course we cannot ascribe great importance to this result; the transfer to molecular forces of what we have found for electrical forces, may be too risky for some. ”