“How long was it before you came out again?”

“Four hours afterwards—­just a little while ago.”

“Then you—­fell asleep?” said Bart.

“Yes, I did, and no blame to me.  I’m no skulker, as you well know.  I never did such a thing before in all my ten years of duty here.  I was doped.”

“How do you know that?” asked Bart.

“I warmed up the coffee and had my lunch,” narrated the watchman.  “Then I settled down for a ten minutes’ comfortable smoke, as I always do.  I felt sort of sickish, right away.  I had noticed that the coffee tasted queer, but I fancied it might have been burned.  Anyhow, half an hour ago I seemed to come out of a stupor, my head fairly splitting, and my stomach burning as though I’d taken poison.  I thought of poison, somehow, and more so than ever as I reached over to see if there was any coffee left, for my throat was dry as a piece of pine board.  There wasn’t, but at the bottom of the pail were two or three little sticky brown dabs.  I tasted the stuff.  It was opium.  I know, for I’ve used it in sickness.  I stumbled out to get the air.  The minute I glanced over at the express office I guessed it all out.  It’s a burglary, right and proper, Stirling, and the fellows who did it knew I was on the watch, got into the switch shanty, fixed the coffee and put me to sleep.”

Bart rapidly turned over in his mind all that the watchman had disclosed.

“See here,” he said promptly, “how many keys are there to the switch shanty?”

“Only one that I know anything of,” responded McCarthy.  “There can’t be many, or the old switchman wouldn’t have to lend me his key.”

“Lem Wacker subbed for him once, didn’t he?” inquired Bart pointedly.

“Yes, for a day or two—­say! you don’t think—­” began the watchman, with a start of suspicion.

“I’m not thinking anything positive,” interrupted Bart—­“I am only seeking information.  When Wacker subbed for the old switchman, did he have a special key?”

“N—­no,” answered the watchman hesitatingly, “for I remember Wacker loaned me the old switchman’s key the first night.  Hold on, though!” cried McCarthy with a spurt of memory, “it comes back to me clear now.  The next night he told me to keep the key till the old switchman came back on duty—­so he must have had an extra one of his own.  They are easily got—­it’s a common, ordinary lock.”

Bart’s lips shut close.  He went outside, looked keenly around, and jumped down from the platform.

The watchman trailed out after him, watching him in a worried, discouraged way.  There was no doubting the word of a trusted employee like McCarthy, and Bart realized that he felt very badly over the matter.

“What is it, Stirling—­have you found anything?” asked the watchman eagerly, as Bart, after inspecting the roadway, still more narrowly regarded the edges of the platform boards, running his finger over them in a critical way.