“Mr. Forbes to see you, sir.”

Had a powerful spring concealed in the seat of his chair been released suddenly, Theydon could not have bounced to his feet with greater speed.  Forbes came in.  He was pale, but self-contained and clear-eyed.

“Forgive an unceremonious visit,” he said.  “I’m glad to find you at home.  I meant to arrive here sooner, but I was detained on business of some importance.”

By this time Bates had closed the door; Theydon explained his presence in the flat by saying that within a few minutes he would have been telephoning again to Old Broad Street.

“Ah!  Did you speak to Macdonald?” said Forbes, dropping into a chair with a curious lassitude of manner which did not escape Theydon.

“Yes.  I have been most anxious to have a word with you—­”

Forbes broke in with a short laugh.

“You would get nothing out of Macdonald,” he said.  “He knows that my visits to the Chinese Embassy are few and far between and generally have to do with—­ but what is it now?  Why should you be so perturbed when I mention the Chinese Embassy?”

Theydon was literally astounded, and did not strive to hide his agitation.  But he was by no means tongue-tied.  Now, most emphatically, was he determined to have done with pretense.  Whether by accident or design, Forbes had placed himself with his back to the window.

The younger man deliberately crossed the room, pulled up the blind, thus admitting the flood of light which comes only from the upper third of a window, and sat down in such a position that Forbes was compelled to turn in order to face him.

“Before you utter another word, Mr. Forbes,” he said gravely, “let me tell you that in my efforts to trace your whereabouts I also called up Fortescue Square.  Miss Forbes came to the telephone.  She said you had gone to the Home Office.  By some feminine necromancy, too, she divined the link which binds you with the death of Mrs. Lester.  She was distressed on your account, and I was hard put to it to extricate myself from the risk of saying something which I might regret.  I—­”

“What do you imply by that remark?” interrupted Forbes, piercing the other with a look that was strangely reminiscent of his daughter’s candid scrutiny.

“I imply the serious fact that I know who visited Mrs. Lester before she met her death.  I not only heard her visitor’s arrival and departure, but saw him at the corner of these mansions while on my way home from Daly’s Theater, and again when he posted a letter in the pillar box on the same corner.  If such unwonted interest on my part in the movements of one who was then a complete stranger surprises you, let me remind you that only a few minutes earlier I had stood by his side at the door of the theater and heard him telling his daughter that he intended to walk to the Constitutional Club.”

Forbes smiled, but uttered no word.  His expression was inscrutable.  His pallor reminded Theydon of the tint of ivory, of that waxen-white Dutch grisaille beloved of fifteenth century illuminators of manuscripts.  His silence was disturbing, almost irritating, his manner singularly calm.