The Ether, or Aether, A medium filling all space. The ether seems to be of the nature of an elastic solid, and, in order to account for the immense rapidity of its vibrations when radiation passes through it, its rigidity must be excessively large compared with its density. From magneto-optic phenomena it seems certain that something of the nature of molecular rotation is going on the ether.
COLLIER’S ENCYCLOPEDIA copyright 1928.