Mrs. Clephane gave a suppressed exclamation and an involuntary motion of protest—­and Mrs. Spencer saw her.

“Mrs. Clephane seems to be concerned lest I accept!” she jeered.

Mrs. Clephane blushed ravishingly, and Harleston caught her in the act; whereupon she blushed still more, and turned away.

“Play acting!” mocked Madeline Spencer—­then, shrugging the matter aside, she turned to the Secretary.  “Since we two are of one mind in the affair before us, your Excellency,” she observed, “I fancy I may take it as settled.  Nevertheless you will pardon me if I don’t depress my aim until we have attended to a little matter; it will occupy us but a moment,” making a step nearer the desk and away from the others, yet still holding them in her eye.

“What is it you wish, madame?” the Secretary inquired a trifle huskily; his throat was becoming somewhat parched by the anxiety of the situation.

“I see you have on your desk a small blue candle; employed, I assume, for melting wax for your private seal,” she went on.  “May I trouble your Excellency to light the aforesaid candle?”

The Secretary promptly struck a match, and managed with a most unsteady hand to touch it to the wick.

As the flame flared up, she drew a narrow envelope from her bag and tossed it on the desk before him.

“Now,” said she, “will you be kind enough to look at the enclosure.”

The Secretary took up the envelope and drew out the sheet.  It was a single sheet of the thinnest texture used for foreign correspondence.  He looked first at one side, then at the other.

“What do you see, sir?” she asked.

“The sheet is blank,” he replied.

“Try the envelope,” she recommended.

He turned it over.  “It also is blank,” he said.

“Sympathetic ink!” Carpenter laughed.

“Just what we are about to see, wise one!” she mocked.  “Now, your Excellency, will you place the envelope in the candle’s flame?”

The Secretary took the envelope by the tip of one corner and held it in the blaze until it was burned to his fingers—­no writing was disclosed.

“Now the letter, please?” she directed.  And when Carpenter would have protested, she cut him short with a peremptory gesture.  “Don’t interrupt, sir!” she exclaimed.

And Carpenter laughed softly and did nothing more—­being, with Harleston, in enjoyment of their chief’s discomfiture.

“The letter—­see—­your Excellency,” she repeated with a bewildering smile.

And as the flame crept down the thin sheet, just ahead of it, apparent to them all, crept also the writing, brought out by the heat.  In a moment it was over; the last bit of the corner burning in a brass tray where the Secretary had dropped it.

“Now, Mr. Harleston,” said Madeline Spencer, lowering her revolver as the final flicker of the flame expired, “I am ready to submit to a search.”