"Why does he have a light at all?" asked the scientist, testily.
"I can hardly answer that," replied Hatch. "I may say, however, that he is of a very nervous temperament, and gets up frequently during the night. He reads occasionally when he can't sleep. In addition to that he has slept with a light going all his life; it's a habit."
"Go on."
"One night he looked for the night lamp, but it had disappeared--at least he couldn't find it--so he lighted the gas again. The fact of the gas having twice before gone out had been dismissed as a serious possibility. Next morning at five o'clock a bell boy, passing through the hall, smelled gas and made a quick investigation. He decided it came from Henley's place, and rapped on the door. There was no answer. It ultimately developed that it was necessary to smash in the door. There on the bed they found Henley unconscious with the gas pouring into the room from the jet which he had left lighted. He was revived in the air, but for several hours was deathly sick."
"Why was the door smashed in?" asked The Thinking Machine. "Why not unlocked?"
"It was done because Henley had firmly barred it," Hatch explained. "He had become suspicious, I suppose, and after the second time he always barred his door and fastened every window before he went to sleep. There may have been a fear that some one used a key to enter."
"Well?" asked the scientist. "After that?"
"Three weeks or so elapsed, bringing the affair down to this morning," Hatch went on. "Then the same thing happened a little differently. For instance, after the third time the gas went out Henley decided to find out for himself what caused it, and so expressed himself to a few friends who knew of the mystery. Then, night after night, he lighted the gas as usual and kept watch. It was never disturbed during all that time, burning steadily all night. What sleep he got was in daytime.
"Last night Henley lay awake for a time; then, exhausted and tired, fell asleep. This morning early he awoke; the room was filled with gas again. In some way my city editor heard of it and asked me to look into the mystery."
That was all. The two men were silent for a long time, and finally The Thinking Machine turned to the reporter.