the Body of the Eye, always is. So that in truth, all Vision is Refracted by an internal Refraction made in ipso Oculo .
And all that I have spoken of Vision holds true of Hearing also, both Refracted and Reflext, and therefore need not be repeated.
Refracted Vision arises from the different Density, Figure, and Magnitude of the Medium, which is somewhat alter'd also by the diverse incidence of the visible Rays. And so it is in Refracted Hearing, all these Causes concur to its Production, and some others to be hereafter consider'd.
Now as any Object (a Man for example) seen through a thicken'd Air, by Refraction appears greater than really he is: So likewise a Sound, heard through the same thicken'd part of the Atmosphere, will be considerably vary'd from what it would seem to be, if heard through a thinner Medium.
And this I call a Refracted Sound: But what this Refraction of Sound is, and how caus'd, may hereafter