“Quite so,” agreed the inspector.  “I am merely reporting the impression of Burke.”

“Has he heard no other sound?” rapped Smith; “one like the cracking of dry branches, for instance?”

“He made no mention of it,” replied Weymouth, staring.

“And what is the plan?”

“One of his cousin’s vans,” said Weymouth, with his slight smile, “has remained behind at Covent Garden and will return late this afternoon.  I propose that you and I, Mr. Smith, imitate Burke and ride down to Upminster under the empty boxes!”

Nayland Smith stood up, leaving his breakfast half finished, and began to wander up and down the room, reflectively tugging at his ear.  Then he began to fumble in the pockets of his dressing-gown and finally produced the inevitable pipe, dilapidated pouch, and box of safety matches.  He began to load the much-charred agent of reflection.

“Do I understand that Burke is actually too afraid to go out openly even in daylight?” he asked suddenly.

“He has not hitherto left his cousin’s plantations at all,” replied Weymouth.  “He seems to think that openly to communicate with the authorities, or with you, would be to seal his death warrant.”

“He’s right,” snapped Smith.

“Therefore he came and returned secretly,” continued the inspector; “and if we are to do any good, obviously we must adopt similar precautions.  The market wagon, loaded in such a way as to leave ample space in the interior for us, will be drawn up outside the office of Messrs. Pike and Pike, in Covent Garden, until about five o’clock this afternoon.  At, say, half past four, I propose that we meet there and embark upon the journey.”

The speaker glanced in my direction interrogatively.

“Include me in the program,” I said.  “Will there be room in the wagon?”

“Certainly,” was the reply; “it is most commodious, but I cannot guarantee its comfort.”

Nayland Smith promenaded the room, unceasingly, and presently he walked out altogether, only to return ere the inspector and I had had time to exchange more than a glance of surprise, carrying a brass ash-tray.  He placed this on a corner of the breakfast table before Weymouth.

“Ever seen anything like that?” he inquired.

The inspector examined the gruesome relic with obvious curiosity, turning it over with the tip of his little finger and manifesting considerable repugnance—­in touching it at all.  Smith and I watched him in silence, and, finally, placing the tray again upon the table, he looked up in a puzzled way.

“It’s something like the skin of a water rat,” he said.

Nayland Smith stared at him fixedly.

“A water rat?  Now that you come to mention it, I perceive a certain resemblance—­yes.  But”—­he had been wearing a silk scarf about his throat and now he unwrapped it—­“did you ever see a water rat that could make marks like these?”