Full Idea
If colours or sounds were in the bodies or objects that cause them, they could not be severed from them, as by glasses, and in echoes by reflection, we see they are; where we know the thing we see is in one place, the appearance in another.
Gist of Idea
Appearance and reality can be separated by mirrors and echoes
Source
Thomas Hobbes (Leviathan [1651], 1.01)
Book Reference
Hobbes,Thomas: 'Leviathan', ed/tr. Macpherson,C.B. [Penguin 1981], p.86