“He is the man we want. I’m going to put it up to you, Plegg, to find him and grab him before he gets next to Lushing. When he is found, buy him, and shoot him out of the country—anywhere where he’ll be out of Lushing’s reach until we get this job done.”

“And if he can’t be bought?”

“Lock him up somewhere and keep him from talking. Now about the bad roof itself: that is where Lushing can hit us the hardest. Give Regnier his tip, and do it to-night. Tell him to have the tunnel re-wired for lights so there won’t be a bulb anywhere near that soft spot. Tell him to keep his men quiet if he has to raise the pay of every man in the three shifts. Then make him understand that the rule against the admission of outsiders must be rigidly enforced, if he has to maintain an armed guard at the portal.”

“That won’t keep Lushing’s inspectors out,” Plegg suggested mildly.

“I’m coming to that. Regnier must see to it that some man of ours who can be trusted is within reach every time an inspector goes in. We don’t care to hurt anybody needlessly, but if one of our hard-rock bullies should happen to get into a scrap with the man who chances to discover that ‘fault’—well, you know what I mean. Mr. Grillage says that place is perfectly safe, and we’re going to take his word for it.”

The first assistant nodded, and the slow smile bared his teeth and wrinkled at the corners of his eyes.

“I certainly owe you an apology,” he said, with the faintest suggestion of irony in his tone; “several of them, in fact. There was a time when I fancied you were going to be too good—to revert to that morning in the Pullman a year ago; and I imagine Mr. Grillage harbored the same inadequate notion. You’ll want to be getting back to headquarters, I suppose: there is an engine due down from the tunnel—there it comes—I’ll flag it for you.”

David caught the eastbound engine, but he did not stop off at the headquarters camp. That was because Crawford, the concrete bridge builder, was at the yard platform to climb to the cab with a bit of news. Under new orders, inspectors had been placed at the three bridges in Crawford’s section, and they were in relays so that there was hardly an hour in the three shifts when one of them was not on duty. Crawford was looking for Plegg, but when he found that the first assistant was unattainable, he unburdened himself to the chief, setting forth the hard conditions.

“Well?” said David, while the engine halted.

“It’s—er—making it sort of difficult for me,” said Crawford, unwilling to go much deeper into the matter in the face of Plegg’s inhibition forbidding detail talk with the boss.