“Search me!” Marston replied.

“There is no occasion to search you, Marston,” she smiled, “I shouldn’t find very much except—­placidity.”

“Placidity has its advantages,” he smiled back.

“It has; that’s why I asked the Chief for you.  You were not as happy in your choice of assistants, Marston.  They are a stupid lot.  You may send them back to New York.  We’ll handle this matter ourselves, with Mrs. Chartrand’s involuntary assistance.”

“Very good, madame!” said Marston.  “The trouble, you see, came with that chap Harleston’s butting into the affair.  Who would have foreseen that he would happen along just at that particular moment and scoop the letter without turning a hair.  It was rotten luck sure.”

“It was all easy enough if the blundering fools had only exercised an atom of sense,” Mrs. Spencer retorted.  “Mrs. Clephane couldn’t deceive a normal two-year-old child; she is as transparent as plate glass.”

“She was clever enough to get rid of the letter in the cab, and to give them the plausible story that it was locked in the hotel safe.  And the hotel safe was the reasonable place for her to leave the letter until she had seen the Ambassador, and someone from the Embassy could return with her and get the letter.”

“Granted—­if Mrs. Clephane were a wise woman and in the service.  She isn’t wise and she isn’t in the service; and both these facts are so apparent that he who runs may read.  She played the Buissards for fools and won.  If they had exercised the intelligence of an infant, they’d have known that she had the letter with her when she left the hotel.  You got a glimmer of light when you thought of the cab—­and Mrs. Clephane told you that Mr. Harleston had stopped and looked at the sleeping horse and then started him toward Dupont Circle.  You came to me to report—­and I, knowing Harleston, solved the remainder of the mystery.  But with Harleston’s entry the affair assumed quite a different aspect; and it is no reflection on you, Marston, that your expedition to his apartment didn’t succeed; though somewhat later Crenshaw did act as a semi-reasonable man, and secured the letter—­only to foozle again like an imbecile.  The play in the hotel last night, as schemed by us, should have gone through and eliminated Clephane and Harleston for a time; but Harleston upset things by his quick action and sense of danger—­moreover, he guessed as to Clephane, for the management got wise and made a search, and the dear lady found Harleston and me in Peacock Alley—­and she pre-empted him.”

Marston blinked and said nothing.

“Why don’t you say something?” she asked sharply.

“What is there to say that you don’t already know,” he replied placidly.