References in classic literature ?
From the point of view that we have been hitherto adopting, we might define them as the appearances of objects at places from which sense-organs and the suitable parts of the nervous system form part of the intervening medium. Just as a photographic plate receives a different impression of a cluster of stars when a telescope is part of the intervening medium, so a brain receives a different impression when an eye and an optic nerve are part of the intervening medium.
Such, then, are the differences of the arts with respect to the medium of imitation.
Only the rare and exceptional genius of Vergil and Milton could use the Homeric medium without loss of individuality: and this quality none of the later epic poets seem to have possessed.