マイケルソン・モーリーの実験
Larmor knew that the Michelson–Morley experiment was accurate enough to detect an effect of motion depending on the factor "(v/c)"2, and so he sought the transformations which were "accurate to second order" (as he put it). Thus he wrote the final transformations (where "x′=x-vt" and "t″" as given above) as: