She stood beside him as he cut the envelope and he took out the single sheet of paper—­on which was an assortment of letters, set down separately and without relation to words.

“What is it,” said she, “a scrambled alphabet?”

“Looks like it!” he smiled.  “As a matter of fact, however, it’s in the Blocked-Out Square cipher—­like the original lett—­”

“Then they could read the original?” she cut in.

“Not unless they have its particular key-word—­”

“Oh, yes; I remember now,” said she.  “Go on!”

“There’s no ‘go on,’” he explained.  “Nor would it help matters if there were.  This letter is spurious; there is nothing to find from it, even if we could translate it.  It’s intended as a plant; either for us or for the Marquis; but I fancy, for us—­so with your permission we will waste no time on it further than to keep alert for its purpose.  When were you to receive the five thousand dollars?”

“I don’t know!” she laughed.

“And the appointment to the German Secret Service?”

“I don’t know; she didn’t say and I didn’t ask.  I was too much occupied with meeting her on her own ground and playing the game.  I was crazy to get the letter so I could show it to you.”

“Which doubtless was what she too wanted; I can’t see through her scheme—­unless it is to muddy the water while the main play is being pulled off.  And our men haven’t discovered a single material thing, though they have had Spencer and all the rest of the gang under shadow since the morning after the cab affair.”

The telephone buzzed.  Mrs. Clephane answered it.

“Yes, Mr. Harleston is here,” she said, passing the receiver to him.

“Hello!” said Harleston.

“Can you make it convenient to drop around here sometime this evening?” Major Ranleigh inquired.

“Will ten o’clock do?”

“Yes.”

“I’ll be there,” said Harleston.

XVII

IN THE TAXI

At ten o’clock Harleston walked into Ranleigh’s office.

“I just wish to ask,” said the Major, “if you want us to pick up the man who met Mrs. Spencer this afternoon.  It’s against your orders, I know, but this chap can be arrested without resulting complications, I think.  He’s an American.”

“Who is he?” Harleston asked.

“Snodgrass, an ex-Captain in the Army; a man of seeming independent means, who lives at the Boulogne.”

“I’m acquainted with him,” returned Harleston.  “I can’t think that he’s crooked.  I reckon Spencer’s figure and face attracted him—­or probably he has known her in Europe.”