are in the engine room or near it all night every night?” began The Thinking Machine.
“I haven’t missed a night in four years,” was the reply.
“Anybody ever come here to see you at night?”
“Never. It’s against the rules.”
“The manager or a hall boy?”
“Never.”
“In the last two months?” The Thinking Machine persisted.
“Not in the last two years,” was the positive reply. “I go on duty every night at seven o’clock, and I am on duty until seven in the morning. I don’t believe I’ve seen anybody in the basement here with me between those hours for a year at least.”
The Thinking Machine was squinting steadily into the eyes of the engineer, and for a time both were silent. Hatch moved about the scrupulously clean engine room and nodded to the day engineer, who sat leaning back against the wall. Directly in front of him was the steam gauge.
“Have you a fireman?” was The Thinking Machine’s next question.
“No. I fire myself,” said the night man. “Here’s the coal,” and he indicated a bin within half a dozen feet of the mouth of the boiler.
“I don’t suppose you ever had occasion to handle the gas meter?” insisted The Thinking Machine.
“Never touched it in my life,” said the other. “I don’t know anything about meters, anyway.”
“And you never drop off to sleep at night for a few minutes when you get lonely? Doze, I mean?”
The engineer grinned good-naturedly.
“Never had any desire to, and besides I wouldn’t have the chance,” he explained. “There’s a time check here,”—and he indicated it. “I have to punch that every half hour all night to prove that I have been awake.”
“Dear me, dear me,” exclaimed The Thinking Machine, irritably. He went over and examined the time check—a revolving paper disk with hours marked on it, made to move by the action of a clock, the face of which showed in the middle.
“Besides there’s the steam gauge to watch,” went on the engineer. “No engineer would dare go to sleep. There might be an explosion.”
“Do you know Mr. Weldon Henley?” suddenly asked The Thinking Machine.
“Who?” asked Burlingame.
“Weldon Henley?”
“No-o,” was the slow response. “Never heard of him. Who is he?”
“One of the tenants, on the second floor, I think.”
“Lord, I don’t know any of the tenants. What about him?”
“When does the inspector come here to read the meter?”
“I never saw him. I presume in daytime, eh Bill?” and he turned to the day engineer.
“Always in the daytime—usually about noon,” said Bill from his corner.
“Any other entrance to the basement except this way—and you could see anyone coming here this way I suppose?”
“Sure I could see ’em. There’s no other entrance to the cellar except the coal hole in the sidewalk in front.”
“Two big electric lights in front of the building, aren’t there?”
“Yes. They go all night.”
A slightly puzzled expression crept into the eyes of The Thinking Machine. Hatch knew from the persistency of the questions that he was not satisfied; yet he was not able to fathom or to understand all the queries. In some way they had to do with the possibility of some one having access to the meter.
“Where do you usually sit at night here?” was the next question.
“Over there where Bill’s sitting. I always sit there.”
The Thinking Machine crossed the room to Bill, a typical, grimy-handed man of his class.
“May I sit there a moment?” he asked.
Bill arose lazily, and The Thinking Machine sank down into the chair. From this point he could see plainly through the opening into the basement proper—there was no door—the gas meter of enormous proportions through which all the gas in the house passed. An electric light in the door made it bright as daylight. The Thinking Machine noted these things, arose, nodded his thanks to the two men and, still with the puzzled expression on his face, led the way upstairs. There the manager was still in his office.
“I presume you examine and know that the time check in the engineer’s room is properly punched every half-hour during the night?” he asked.
“Yes. I examine the dial every day—have them here, in fact, each with the date on it.”
“May I see them?”
Now the manager was puzzled. He produced the cards, one for each day, and for half an hour The Thinking Machine studied them minutely. At the end of that time, when he arose and Hatch looked at him inquiringly, he saw still the perplexed expression.
After urgent solicitation, the manager admitted them to the apartments of Weldon Henley. Mr. Henley himself had gone to his office in State Street. Here The Thinking Machine did several things which aroused the curiosity of the manager, one of which was to minutely study the gas jets. Then The Thinking Machine opened one of the front windows and glanced out into the street. Below fifteen feet was the sidewalk; above was the solid front of the building, broken only by a flagpole which, properly roped, extended from the hall window of the next floor above out over the sidewalk a distance of twelve feet or so.
“Ever use that flagpole?” he asked the manager.
“Rarely,” said the manager. “On holidays sometimes—Fourth of July and such times. We have a big flag for it.”
From the apartments The Thinking Machine led the way to the hall, up the stairs and to the flagpole. Leaning out of this window, he looked down toward the window of the apartments he had just left. Then he inspected the rope of the flagpole, drawing it through his slender hands slowly and carefully. At last he picked off a slender thread of scarlet and examined it.
“Ah,” he exclaimed. Then to Hatch: “Let’s go, Mr. Hatch. Thank you,” this last to the manager, who had been a puzzled witness.
Once on the street, side by side with The Thinking Machine, Hatch was bursting with questions, but he didn’t ask them. He knew it would be useless. At last The Thinking Machine broke the silence.
“That girl, Miss Regnier, was murdered,” he said suddenly, positively. “There have been four attempts to murder Henley.”
“How?” asked Hatch, startled.
“By a scheme so simple that neither you nor I nor the police
