“In a week, no doubt,” rejoined Knightley, “I shall be less sensible of its humour.  But to-night—­well, I am home in Tangier, and that contents me.  Nothing has changed.”  At that he stopped suddenly.  “Nothing has changed?” This time the phrase was put as a question, and with the halting timidity which he had shown before.  No one answered the question.  “No, nothing has changed,” he said a third time, and again his eyes began to travel wistfully from face to face.

Tessin abruptly turned his back; Shackleton blinked his eyes at the ceiling with altogether too profound an unconcern; Scrope reached out for the wine, and spilt it as he filled his glass; Wyley busily drew diagrams with a wet finger on the table.

All these details Knightley remarked.  He laid down his fork, he rested his elbow on the table, his forehead upon his hand.  Then absently he began to hum over to himself a tune.  The rhythm of it was somehow familiar to the Surgeon’s ears.  Where had he heard it before?  Then with a start he remembered.  It was this very rhythm, that very tune, which Scrope’s fingers had beaten out on the table when he first saw Knightley.  And as he had absently drummed it then, so Knightley absently hummed it now.

Surely, then, the tune had some part in the relations of the two men—­perhaps a part in this story.  “A foolish song.”  The words flashed into Wyley’s mind.

“She was singing a foolish song.”  What if the tune was the tune of that song?  But then—­Wyley’s argument came to a sudden conclusion.  For if the tune was the tune of that song, why, then Knightley must know the truth, since he remembered that song.  Was Scrope right after all?  Was Knightley playing with him?  Wyley glanced at Knightley in the keenest excitement.  He wanted words fitted to that tune, and in a little the words came—­first one or two fitted here and there to a note, and murmured unconsciously, then an entire phrase which filled out a bar, finally this verse in its proper sequence: 

  “No, no, fair heretick, it needs must be
    But an ill love in me,
    And worse for thee;
  For were it in my power
  To love thee now this hour
    More than I did the last,
  ’Twould then so fall
  I might not love at all. 
  Love that can flow....”

And then the song broke off, and silence followed.  Wyley looked again at Knightley, but the latter had not changed his position.  He still sat with his face shaded by his hand.

The Surgeon was startled by a light touch on the arm.  He turned with almost a jump, and he saw Scrope bending across the table towards him, his eyes ablaze with an excitement no less keen than his own.

“He knows, he knows!” whispered Scrope.  “It was that song she was singing; at that word ‘flow’ he pushed open the door of the room.”

Knightley raised his head and drew his hand across his forehead, as though Scrope’s whisper had aroused him.  Scrope seated himself hurriedly.