three o'clock
All the world was one gigantic blinding glare , silent , motionless . `` If it gets much hotter , '' murmured the dentist again , moving his head from side to side , `` if it gets much hotter , I don ' know what I 'll do . '' Steadily the heat increased . At three o'clock it was even more terrible than it had been at noon . `` Ai n't it EVER going to let up ? '' groaned the dentist , rolling his eyes at the sky of hot blue brass . Then , as he spoke , the stillness was abruptly stabbed through and through by a shrill sound that seemed to come from all sides at once .