“Yes, I can remember that. It appears to me his air fluid was supposed to kill all sound produced by metal but not that produced by the human voice. Yes, I know all sound is just waves of air. But there are different qualities of sound, aren’t there? Well, this fluid of his was of such a subtle nature that it neutralized and balked only the waves which were caused by the ring of metal.

I was to operate the projection machine from the roof of the City Hall.” He raised a shaky finger to the one skyscraper outlined against the setting sun. “On that roof froni which the central tower springs the machine was to be installed. It’s the highest point in the city...

What happened when you turned it on?” I urged.

“Nothing!” He spoke as one coming out of a dream. “Nothing except silence . . . dead silence!”

“What did you do ?”

“I waited for I hardly knew what. At last I ent to the parapet and looked over. ...” “Well? What did you see?”

“I saw hell ... a silent hell! The street was thick with people. All up and down as far as I could see the buildings were emptying just as they do after a heavy earthquake. Seems like folks had the terrified feeling that goes with a great calamity and wanted to get clear of the buildings . . . out in the open. And they did the worst thing they could do. They stampeded toward the City Hall Square. Directly below me they swarmed in a great eddying mass, like a silent whirlpool. Two street cars, not being able to hear warning bells, collided and made a sort of snag in the rushing torrent. People kept running out to help those already injured and getting knocked down themselves . . . automobiles smashed here and there, injuring more . . . everywhere lay men and women and children injured or dying without audible cries or groans... it was ghastly... like a motion picture of warfare ...

"Why didn’t you turn the infernal machine off when you saw what it was doing?” I offered.

“That’s the terrible part! I couldn’t!’’ and I saw tears in his pale blue eyes. “I tried . . . oh, how I tried . . . but I forgot how...”

“Why didn’t you get your brother to come and turn it off?”