the enormous amount of money required to finance these operations and keep all these spies under pay.  While we try to thwart their plans as we find them, all our efforts are constantly directed toward discovering who controls and finances their damnable system.  We seldom if ever arrest any of the spies we track down, but keep watching, watching, watching, hoping that sooner or later the master-spy will be betrayed into our hands.”

“You don’t think then,” said Jane disappointedly, “that old Mr. Hoff is one of the important spies.”

“We can’t tell yet.  He may be just one of the cogs—­perhaps what they call a control-agent.  We don’t know yet.  Germany has been building up her spy system forty years, and it is ingenious beyond imagination.  Her codes are the most difficult in the world.  It took the French three years and a half to decipher a code despatch from Von Bethmann Hollweg to Baron von Schoen.  By the time they had it deciphered in Paris the Germans had discovered what they were doing and had changed the code.  It is seldom any one of the German spies knows much about the work that other spies are doing.  The rank and file merely get orders to go and do such a thing, or find out about such a thing.  Often they are not told what they are doing it for.  They obey their orders implicitly in detail and make their reports, get new orders and go on to do something else.  Only their master spy-council here knows what the summary of their efforts amounts to.  Arresting old Hoff, or a dozen more like him, would not cripple them much.  Other men would be assigned in their places, and the nefarious work would go on.”

“I don’t know,” insisted Jane thoughtfully.  “I believe that old Mr. Hoff is a far bigger spoke in the wheel than you think.  I watched his face as I followed him this morning.  He is a man of great intelligence, and I should judge a man of education.”

“They’d hardly be using a man of that sort to carry messages,” objected Carter.  “Maybe you’re right.  We have not watched him long enough to find out.  We’ve got nothing yet on the young fellow.  Maybe he’s the real boss of the outfit.  At any rate he is the one the Chief is anxious to have you keep tabs on.  Are you to see him again?”

“Oh, yes,” the girl answered quickly, a touch of color coming to her face, “I think so.  I asked him to come to see me.  I think—­in fact I’m sure—­he will.  Do you want me to watch the bookshop to see if they leave any more messages there?”

“No,” said Carter.  “I’ve got one of my men assigned to that.  You keep after the young fellow.  Say, does your father keep an automobile?”

“Yes, but it’s been put up for the winter.  We’re going to bring it out as soon as Dad can find a chauffeur.  Our man—­the one we had last year—­has been drafted, and good chauffeurs are scarce now.  Why did you ask?”

“I’ll find you a chauffeur,” said Carter decisively.

“You mean”—­Jane hesitated—­“a detective?”