“How long has he been in London now?” asked Smith.

So far as could be ascertained from New Inn Court (replied Scotland Yard) roughly a week.

My friend left the telephone and began restlessly to pace the room.  The charred briar was produced and stuffed with that broad cut Latakia mixture of which Nayland Smith consumed close upon a pound a week.  He was one of those untidy smokers who leave tangled tufts hanging from the pipe-bowl and when they light up strew the floor with smoldering fragments.

A ringing came, and shortly afterwards a girl entered.

“Mr. James Weymouth to see you, sir.”

“Hullo!” rapped Smith.  “What’s this?”

Weymouth entered, big and florid, and in some respects singularly like his brother, in others as singularly unlike.  Now, in his black suit, he was a somber figure; and in the blue eyes I read a fear suppressed.

“Mr. Smith,” he began, “there’s something uncanny going on at Maple Cottage.”

Smith wheeled the big arm-chair forward.

“Sit down, Mr. Weymouth,” he said.  “I am not entirely surprised.  But you have my attention.  What has occurred?”

Weymouth took a cigarette from the box which I proffered and poured out a peg of whisky.  His hand was not quite steady.

“That knocking,” he explained.  “It came again the night after you were there, and Mrs. Weymouth—­my wife, I mean—­ felt that she couldn’t spend another night there, alone.”

“Did she look out of the window?” I asked.

“No, Doctor; she was afraid.  But I spent last night downstairs in the sitting-room—­and I looked out!”

He took a gulp from his glass.  Nayland Smith, seated on the edge of the table, his extinguished pipe in his hand, was watching him keenly.

“I’ll admit I didn’t look out at once,” Weymouth resumed.  “There was something so uncanny, gentlemen, in that knocking—­ knocking—­in the dead of the night.  I thought”—­his voice shook—­“of poor Jack, lying somewhere amongst the slime of the river—­and, oh, my God! it came to me that it was Jack who was knocking—­and I dare not think what he—­what it—­ would look like!”

He leaned forward, his chin in his hand.  For a few moments we were all silent.

“I know I funked,” he continued huskily.  “But when the wife came to the head of the stairs and whispered to me:  `There it is again.  What in heaven’s name can it be’—­I started to unbolt the door.  The knocking had stopped.  Everything was very still.  I heard Mary—­his widow—­sobbing, upstairs; that was all.  I opened the door, a little bit at a time.”

Pausing again, he cleared his throat, and went on: 

“It was a bright night, and there was no one there—­not a soul.  But somewhere down the lane, as I looked out into the porch, I heard most awful groans!  They got fainter and fainter.  Then—­I could have sworn I heard someone laughing!  My nerves cracked up at that; and I shut the door again.”