Unpublished letter, 'On a new property of light possessed by the second surfaces of transparent bodies' from David Brewster to Sir Joseph Banks Brewster describes a discovery he made during his experiments on light that is reflected from the second surfaces of transparent bodies, finding that this reflected light is polar. He explains this property in detail and includes experimental results. Subject: Physics Read to the Royal Society on 23 January 1815. 9 January 1815