“Well?  On that night when I came back?”

“I saw you in the road from my window, and then motioning you to be silent, I disappeared from the window.”

“Yes, I remember,” said Chayne, eagerly.  He began to think that the cocaine was after all going to fit in with the incidents of that night.

“Walter Hine and my father were going up to bed.  I heard them on the stairs.  They were going earlier than usual.”

“You are sure?” interrupted Chayne.  “Think well!”

“Much earlier than usual, and they were quarreling.  At least, Walter Hine was quarreling; and my father was speaking to him as if he were a child.  That hurt his vanity and made him worse.”

“Your father was provoking him?”

Sylvia’s forehead puckered.

“I could not say that, and be sure of it.  But I can say this.  If my father had wished to provoke him to a greater anger, it’s in that way that he would have done it.”

“Yes.  I see.”

“They were speaking loudly—­even my father was—­more loudly than usual—­especially at that time.  For when they went up-stairs, they usually went very quietly”; and again Chayne interrupted her.

“Your father might have wanted you to hear the quarrel?” he suggested.

Sylvia turned to him curiously.

“Why should he wish that?” she asked, and considered the point.  “He might have.  Only, on the other hand, they were earlier than usual.  They would not be so careful to go quietly; I was likely to be still awake.”

“Exactly,” said Chayne.

For in the probability that Sylvia would be still awake, would hear the violent words of Hine, and would therefore be an available witness afterward, Chayne found the reason both of the loudness of Garratt Skinner’s tones and his early retirement for the night.

“Did you hear what was said?  Can you repeat the words?” he asked.

“Yes.  My father was keeping something from Mr. Hine which he wanted.  I have no doubt it was the cocaine,” and she repeated the words.

“Yes,” said Chayne.  “Yes,” in the tone of one who is satisfied.  The incident of the lighted room and the shadow on the ceiling were clear to him now.  A quarrel of which there was a witness, a quarrel all to the credit of Garratt Skinner since it arose from his determination to hinder Walter Hine from poisoning himself with drugs—­at least, that is how the evidence would work out; the quarrel continued in Walter Hine’s bedroom, whither Garratt Skinner had accompanied his visitor, a struggle begun for the possession of the drug, begun by a man half crazy for want of it, a blow in self-defence delivered by Garratt Skinner, perhaps a fall from the window—­that is how Chayne read the story of that night, as fashioned by the ingenuity of Garratt Skinner.

But on one point he was still perplexed.  The story had not been told out to its end that night:  there had come an unexpected shout, which had interrupted it, and indeed forever had prevented its completion on that spot.  But why had it not been completed afterward, during the next few months, somewhere else?  It had not been completed.  For here was Sylvia with all her fears allayed, continuing the story of those months.