Evening Republican, Volume 17, Number 88, Rensselaer, Jasper County, 12 April 1913 — Shadows of .Sound. [ARTICLE]

Shadows of .Sound.

As there are shadows that Interfere with sight so also there are “shadows” that interfere with hearing. This fact Is well known to pilots., When, as in dense fogs, the boat is guided largely by the sense of hearing, thbre is a constant risk that these so-called “shadows” may cut off the sound of the fog horns. In certain cases the sound waves seem to “jump” like bounding balls. At the distance of a mile the sound is heard perfectly, at two miles it may be impossible to hear it, while a mile further on it may begin to be audible once more.—Harper’s Weekly.