ECHO LOUDER THAN THE SOUND.

Rodney and Otamatea Times, Waitemata and Kaipara Gazette, 1 October 1913, Page 7

ECHO LOUDER THAN THE SOUND.

To cause the echo of a seuad to be louder than the sound that caused it seems an impassibility, but under oertam eonditioms this can happe*, and the /echo is sometimes many times greater i» sound volume th»» frfce eriginal noise that produced it.

This happens away up in the air. For instance, if an aviator is, say, one or tw» thousand feet above the ground fires a revolver, there if a brief time when nothing is heard. /The aviator caa. see, the smoke from the muzzle of the revolver, then waits a little, then the sound oonaes to him, not like the bharp report of a revolver, but more like a quick peal of thunder—loud and sharp aad really several times greater in sound volume than tke actual report of the revolver.

The cause of this is that the air below is much more dense, whjle up above it is lighter, and there are n© hills and trees and buildings to help muffle the sound.,'so it Gomes vtft on sound waves witk increas-inf noise. Having" no s*lid background ar«und and about the aviator, the rebound »f the soumd wavesr is* greater up tSere than «n the ground.

It is said a mam m a hallo«n stay lower an explosive »a a o«i4 several huridr«d feet kelew and set-it off with an electric wir» amd bAttwy. Tkere.is a sharp little like ike report of a rifle, then eemeß the mest terrifying noise, Kke a great ■ kwr«t «f thunder—.the l«udest ever heard. The actual explosien did a*t make anywhere mear this asaouat «f moise, but the air being M«ok a»«^e denso keiow eanses the lim« •€ leaat resistamae to b« straight up, and s© tke soumd waves expand mightily ,im am^ upward tKreetien, im«reaximg the sovmd.