Note 134 — APHORISMS—BOOK II ON THE INTERPRETATION OF NATURE, OR THE REIGN OF MAN (continued 2)
Reading edition
The polished surface of the glass causes the reflection in this case, and not the air; and a hat or other black surface put behind the window in the daytime will enable the glass to reflect distinctly for the same reason, namely, that the reflected rays are not mixed and confused with those transmitted from the other side of the window.