Evening Republican, Volume 59, Number 84, Rensselaer, Jasper County, 30 April 1917 — EFFECT OF WIND ON SOUND [ARTICLE]

EFFECT OF WIND ON SOUND

Difference* in Strength of Wind la What Prevent* the Spread of Sound. L One of the government scientists gives an interesting explanation of the action of the wind in preventing the spread of sound. It is, he claims, not the wind, as such, that prevents sound from traveling against It, but differences in the strength of the wind. If, for instance, the wind is stronger at one side, its effect will be to tilt the sound waves In one direction or another. Differences of temperature in the air also cause deflection of the waves of sound. Other atmospheric causes exist which deflect sound from a straight course 'and prevent it from going as far In a certain direction as It may have been expected to go. Some of the sirens in this country, says this scientist, produce sound* which ought theoretically to be audible at a distance of 1,500 miles, but, in fact, the authorities are satisfied if they are heard only two miles away. The reason for the discrepancy between calculation and experiment was probably atmospheric deflection of the sound.