Note 188 — LETTERS ON SCIENCE.

See the Artist and Amateur’s Magazine, p. 313, where the author of the letter, to which this is a reply, adduced in support of his views the following experiment, viz.: to put a tub filled with clear water in the sunlight, and then taking an opaque screen with a hole cut in it, to place the same in such a position as to intercept the light falling upon the tub. Then, he argued, cover the hole over, and the tub will be in shadow; uncover it again, and a patch of light will fall on the water, proving that water is not “insusceptible of light as well as shadow.”