“Oh, listen,” interrupted Jane, all excitement.  “I believe I can read this cipher.  The number of letters in the word in big type at the beginning of the advertisement is the key.  See, this word here is ’remember’—­that has eight letters.  Read every eighth word in this advertisement.  I’ve underlined them.”

Fleck took the paper quickly from her hand and he and Carter bent eagerly over it to see if her theory was correct.

     Remember

Please, that our new paste, Dento, will stop decay of your teeth.  Sound teeth are passports to good health and comfort.  No good business man can risk ill health.  It is closely allied with failure.  The teeth if not watched are quickly gone.

     USE DENTO

     A genuine, safe, pleasing paste for the
     teeth, prepared and sold only by the
     Auer Dental Company, New York.

“Stop passports business, closely watched,” repeated Fleck aloud.  “That certainly makes sense and fits the facts, too.  In the last few days we have drawn the net closely around a gang of supposed Scandinavians who have been busy supplying passports to suspicious-looking travelers.  Let’s see the other advertisement.”

Excitedly the three of them read it together as Fleck underscored every fourth word.

     DON’T

Forget it is imperative for one and all to use cleansing agents on teeth that leave no bad results. “Ship more of that wonder-working paste immediately. Workers, employers, wives, all ready to commend it. Friday’s supply gone,” writes a druggist, to whom a big shipment was made last week.

     USE DENTO

     A genuine, safe, pleasing paste for the
     teeth, prepared and sold only by the
     Auer Dental Company, New York.

“Imperative all agents leave ship.  Wonder-workers ready Friday,” read Fleck.  “That’s surely a message, a warning to Germany’s agents to get off some ship or ships before they are destroyed.  You, Miss Strong, have heard old Otto talk about the wonder-workers, whatever they are, being nearly ready.  I guess he means bombs—­bombs to blow up American transports.  This message says they will be ready Friday.”

“And to-morrow’s Friday,” said Jane.

CHAPTER XIII

THE SEALED PACKET

“Is this Miss Strong?”

Jane, her face blanching, held the receiver in wavering hands for a moment before she could muster courage to answer.  She had recognized Frederic Hoff’s voice speaking.  What could he want with her now?

“It is Miss Strong,” she managed to answer.

“This is Frederic Hoff.  May I come in for a moment?  It is most important.”