An Optical Phenomenon

Abstract

CAPT. C. J. P. CAVE'S letter in NATURE of October 18 reminds me of a similar effect experienced when travelling in a coupé compartment at the rear of a train some years ago. From a window at the back of the coupé one could watch the ever-disappearing landscape as the train travelled along. The impression created was that every object seen appeared to be rushing away from the train. But a stranger sensation occurred when turning my eyes from the window to objects in the coupé, for, during a space of a few seconds, they appeared to be moving rapidly in a contrary direction.