We may easily satisfy ourselves that, in every instance in which the sensation of sound is excited, the body whence the sound proceeds must have been thrown, by a blow or other means, into a state of agitation or tremor, implying the existence of a vibratory motion, or motion to and fro, of the particles of which it consists.
Thornton, an old colleague in the India House, "has carried out her long-cherished scheme (about which she tells me she consulted you) of a ` vibratory ' for me, and has made a pleasant covered walk, some 30 ft.
Thus, you see, with my herbarium, my vibratory, and my semi-circumgyratory, I am in clover; and you may imagine with what scorn I think of the House of Commons, which, comfortable club as it is said to be, could offer me none of these comforts, or, more perfectly speaking, these necessaries of life."
Although Robert Hooke in 1668 and Ignace Pardies in 1672 had adopted a vibratory hypothesis of light, the conception was a mere floating possibility until Huygens provided it with a sure foundation.
Hearing, and objectively the vibratory motion which produces the sensation of sound.