“The train is confoundedly late!” he exclaimed irritably.  “Seven minutes behind time already!”

“A few minutes more or less are not of much consequence,” said Thorndyke.

“No, of course not; but still—­Ah, thank Heaven, here we are!”

He thrust his head out of the off-side window, and gazed eagerly down the line; then, leaping to his feet, he bustled out on to the platform while the train was still moving.

Even as we alighted a warning bell rang furiously on the up-platform, and as Mr. Barton hurried us through the empty booking-office to the outside of the station, the rumble of the approaching train could be heard above the noise made by our own train moving off.

“My carriage doesn’t seem to have arrived yet,” exclaimed Mr. Barton, looking anxiously up the station approach.  “If you will wait here a moment, I will go and make inquiries.”

He darted back into the booking-office and through it on to the platform, just as the up-train roared into the station.  Thorndyke followed him with quick but stealthy steps, and, peering out of the booking-office door, watched his proceedings; then he turned and beckoned to me.

“There he goes,” said he, pointing to an iron footbridge that spanned the line; and, as I looked, I saw, clearly defined against the dim night sky, a flying figure racing towards the “up” side.

It was hardly two-thirds across when the guard’s whistle sang out its shrill warning.

“Quick, Jervis,” exclaimed Thorndyke; “she’s off!”

He leaped down on to the line, whither I followed instantly, and, crossing the rails, we clambered up together on to the foot-board opposite an empty first-class compartment.  Thorndyke’s magazine knife, containing, among other implements, a railway-key, was already in his hand.  The door was speedily unlocked, and, as we entered, Thorndyke ran through and looked out on to the platform.

“Just in time!” he exclaimed.  “He is in one of the forward compartments.”

He relocked the door, and, seating himself, proceeded to fill his pipe.

“And now,” said I, as the train moved out of the station, “perhaps you will explain this little comedy.”

“With pleasure,” he replied, “if it needs any explanation.  But you can hardly have forgotten Mr. James’s flattering remarks in his report of the Greek Street incident, clearly giving the impression that the mysterious document was in my possession.  When I read that, I knew I must look out for some attempt to recover it, though I hardly expected such promptness.  Still, when Mr. Barton called without credentials or appointment, I viewed him with some suspicion.  That suspicion deepened when he wanted us both to come.  It deepened further when I found an impossible quantity of arsenic in his sample, and it gave place to certainty when, having allowed him to select the trains by which we were to travel, I went up to the laboratory and examined the time-table; for I then found that the last train for London left Rexford ten minutes after we were due to arrive.  Obviously this was a plan to get us both safely out of the way while he and some of his friends ransacked our chambers for the missing document.”