Edmund Taylor Whittaker

“ Throughout the nineteenth century it was thought that absolute motion in space, or at any rate absolute motion relative to the general body of stars, could be determined by the astronomical study of proper motions; and the Sun was supposed to have "an absolute velocity of about fifteen miles a second towards a point in the constellation Hercules." ”

“ Celestial mechanics, which has hitherto been based on the Newtonian laws of motion, is profoundly affected by the discoveries which have been made in recent years regarding measurements of space, time, and force. ”

“ For instance, two electric charges repel each other according to the law of electrostatics, but if the charges are in motion with equal and parallel velocities at right angles to the line joining them, the moving charges will be equivalent to elements of parallel currents, and the electrostatic repulsion will consequently be weakened by an electro-dynamic attraction superposed on it. ”

“ It will be seen that under these circumstances we cannot hope to measure experimentally either the Fitzgerald contraction itself or any other effect of motion through the æther so long as we ourselves move with the moving system, for all these effects of motion form part of a general sympathetic change which takes place in everything with which we can operate, so that no alteration in the mutual relations of the members of the system is recognisable from within. ”

“ The obvious deduction from this is, that the forces of cohesion which determine the size of material bodies are really electrical in their origin: if this be accepted, the Fitzgerald contraction follows as a necessary consequence. ”