Show I Sound W. W Waves aves Visible o on Firing Line Interesting data regarding the visibility visibility bulLy o of sound waves have recently been published in in jn letters from men meu at the front One writer tells of seeing curved lines of light alternating with dark bands moving swiftly across the sky while heavy cannonading was In progress I A A. second writer speaks of ot witnessing witness witness- ing a series of or arcs of ot light ht traveling across a cloud flecked sky Scientists attribute these phenomena to sound waves which originate with th the explosions explosions ex ex- ex- ex and spread in all aU directions like hike enlarging spheres resulting in successive and alternate belts of ot rarefied rare rare- fied fled anti and compressed air says Popular lar Mechanics Under certain atmospheric atmos atmos- conditions with the sun in m the proper position portions of or these theBe spreading waves become visible in m the form of moving arcs of light I |