HISS TO DRIVE AWAY FOGS

Hawke's Bay Herald-Tribune, Issue 71, 10 April 1937, Page 11

HISS TO DRIVE AWAY FOGS

Possibility of tbe Future • . : • : £

rpHE POSSIBILITY tbat natural science can develop a bissing sound tremendous enougb to sbake tbe fog out of airports was presented to tbe annual meeting of the Ameriean Institute of Mining and MetaDurgical Engineers. The fog idea is a development of tbe whistle made to clean smoke out of chimneys, wbicb was announced by tbe United States Bureal of Mines at Washington. "Tbe same tbing," said Dr. R. S. Dean, of the Bureau of Mines, "'would work in fog over an airport. provided any one knew bow to produce sufficient intensity of sound. At present no sucb intensity can be made by any means we know of, but I would not say it will be impossible to do tbis in tbe future." Tbe noise, be explained, would not be nnpleasant. ' It would be so bigb pitched tbat probably most persons could not bear it at all. Its effect would be'to sbake tbe fog into droplets of rain; Inside a chimney tbe .whistle works well, because tbo sound is ■ intensificd

sufficiently tbere by tbe echoes, Or more stric'tly., tEe resonances. The new chimney device was explained to tbe engineers by H. W. St. Clair of tbe Bureau of Mines. j It was developed for emelters, to recover gold, silver, copper, zinc, lead and arsenie going np tbe chimney as smoke. It should work, Mr. St Clair said, in any chimney, and probably would bo inexpensive. Tbe equipment is an electric whistle and a reflector, to bounce tbe sound waves, back and fortb tbe lengtb of the chimney. The reflector is set so tbat sound waves superimpose. The agitation of the air at the points where the waves pile up throws smoke, dust and all other kinds of paTticles into the spaces between tbe noise knots, or nodes. j In tbe qniet areas tbe partieles stiek together, and tbe resulting balls fall of tbeir own weigbt. • Teehnically, in tbese areas tbe Brownian movement of tbe air is slowed, and tbat is why tbe small partieles get together,