And yet neither man nor woman passed us who fitted the description.  Train after train emptied its human freight, yet the pale man with the concave nose and the peculiar ear, accompanied perhaps by a lady, did not pass us.

At last the incoming stream began to dwindle down.  It was long past the time when the counterfeiters should have arrived if they had started on any reasonable train.

“Perhaps they have gone up to Montreal, instead,” I ventured.

Kennedy shook his head.  “No,” he answered.  “I have an idea that I was mistaken about the money being kept at Riverwood.  It would have been too risky.  I thought it out on the way back this morning.  They probably kept it in a safe deposit vault here.  I had figured that they would come down and get it and leave New York after last night’s events.  We have failed—­they have got by us.  Neither the ‘portrait parle’ nor the ordinary photography nor any other system will suffice alone against the arch-criminal back of this, I’m afraid.  Walter, I am sore and disgusted.  What I should have done was to accept Burke’s offer—­surround the house with a posse if necessary, last night, and catch the counterfeiters by sheer force.  I was too confident.  I thought I could do it with finesse, and I have failed.  I’d give anything to know what safe deposit vault they kept the fake money in.”

I said nothing as we strolled away, leaving Burke’s man still to watch, hoping against hope.  Kennedy walked disconsolately through the station, and I followed.  In a secluded part of the waiting-room he sat down, his face drawn up in a scowl such as I had never seen.  Plainly he was disgusted with himself—­with only himself.  This was no bungling of Burke or any one else.  Again the counterfeiters had escaped from the hand of the law.

As he moved his fingers restlessly in the pockets of his coat, he absently pulled out the little pieces of sponge and the ether bottle.  He regarded them without much interest.

“I know what they were for,” he said, diving back into his pocket for the other things and bringing out the sharp little knives in their case.  I said nothing, for Kennedy was in a deep study.  At last he put the things back into his pocket.  As he did so his hand encountered something which he drew forth with a puzzled air.  It was the piece of paraffin.

“Now, what do you suppose that was for?” he asked, half to himself.  “I had forgotten that.  What was the use of a piece of paraffin?  Phew, smell the antiseptic worked into it.”

“I don’t know,” I replied, rather testily.  “If you would tell me what the other things were for I might enlighten you, but—­”

“By George, Walter, what a chump I am!” cried Kennedy, leaping to his feet, all energy again.  “Why did I forget that lump of paraffin?  Why, of course—­I think I can guess what they have been doing—­of course.  Why, man alive, he walked right past us, and we never knew it.  Boy, boy,” he shouted to a newsboy who passed, “what’s the latest sporting edition you have?”