“Excellently, thank you,” Francis replied.

“And so far,” Sir Timothy went on, with a faint smile, “you find my entertainment normal?  You have no question yet which you would like to ask?”

“Only one—­what do you do with your launch up the river on moonless nights, Sir Timothy?”

Sir Timothy’s momentary silence was full of ominous significance.

“Mr. Ledsam,” he said, after a brief pause, “I have given you almost carte blanche to explore my domains here.  Concerning the launch, however, I think that you had better ask no questions at present.”

“You are using it to-night?” Francis persisted.

“Will you come and see, my venturesome guest?”

“With great pleasure,” was the prompt reply.

Sir Timothy glanced at his watch.

“That,” he said, “is one of the matters of which we will speak at a quarter to twelve.  Meanwhile, let me show you something.  It may amuse you as it has done me.”

The three moved back towards one of the arched openings which led into the ballroom.

“Observe, if you please,” their host continued, “the third couple who pass us.  The girl is wearing green—­the very little that she does wear.  Watch the man, and see if he reminds you of any one.”

Francis did as he was bidden.  The girl was a well-known member of the chorus of one of the principal musical comedies, and she seemed to be thoroughly enjoying both the dance and her partner.  The latter appeared to be of a somewhat ordinary type, sallow, with rather puffy cheeks, and eyes almost unnaturally dark.  He danced vigorously and he talked all the time.  Something about him was vaguely familiar to Francis, but he failed to place him.

“Notwithstanding all my precautions,” Sir Timothy continued, “there, fondly believing himself to be unnoticed, is an emissary of Scotland Yard.  Really, of all the obvious, the dry-as-dust, hunt-your-criminal-by-rule-of-three kind of people I ever met, the class of detective to which this man belongs can produce the most blatant examples.”

“What are you going to do about him?” Francis asked.

Sir Timothy shrugged his shoulders.

“I have not yet made up my mind,” he said.  “I happen to know that he has been laying his plans for weeks to get here, frequenting Soto’s and other restaurants, and scraping acquaintances with some of my friends.  The Duke of Tadchester brought him—­won a few hundreds from him at baccarat, I suppose.  His grace will never again find these doors open to him.”

Francis’ attention had wandered.  He was gazing fixedly at the man whom Sir Timothy had pointed out.

“You still do not fully recognise our friend,” the latter observed carelessly.  “He calls himself Manuel Loito, and he professes to be a Cuban.  His real name I understood, when you introduced us, to be Shopland.”

“Great heavens, so it is!” Francis exclaimed.