“There is something else,” I said hesitatingly, at the last.  “Halsey, I have never told this even to Gertrude, but the morning after the crime, I found, in a tulip bed, a revolver.  It—­it was yours, Halsey.”

For an appreciable moment Halsey stared at me.  Then he turned to Gertrude.

“My revolver, Trude!” he exclaimed.  “Why, Jack took my revolver with him, didn’t he?”

“Oh, for Heaven’s sake don’t say that,” I implored.  “The detective thinks possibly Jack Bailey came back, and—­and the thing happened then.”

“He didn’t come back,” Halsey said sternly.  “Gertrude, when you brought down a revolver that night for Jack to take with him, what one did you bring?  Mine?”

Gertrude was defiant now.

“No.  Yours was loaded, and I was afraid of what Jack might do.  I gave him one I have had for a year or two.  It was empty.”

Halsey threw up both hands despairingly.

“If that isn’t like a girl!” he said.  “Why didn’t you do what I asked you to, Gertrude?  You send Bailey off with an empty gun, and throw mine in a tulip bed, of all places on earth!  Mine was a thirty-eight caliber.  The inquest will show, of course, that the bullet that killed Armstrong was a thirty-eight.  Then where shall I be?”

“You forget,” I broke in, “that I have the revolver, and that no one knows about it.”

But Gertrude had risen angrily.

“I can not stand it; it is always with me,” she cried.  “Halsey, I did not throw your revolver into the tulip bed.  I—­think—­ you—­did it—­yourself!”

They stared at each other across the big library table, with young eyes all at once hard, suspicious.  And then Gertrude held out both hands to him appealingly.

“We must not,” she said brokenly.  “Just now, with so much at stake, it—­is shameful.  I know you are as ignorant as I am.  Make me believe it, Halsey.”

Halsey soothed her as best he could, and the breach seemed healed.  But long after I went to bed he sat down-stairs in the living-room alone, and I knew he was going over the case as he had learned it.  Some things were clear to him that were dark to me.  He knew, and Gertrude, too, why Jack Bailey and he had gone away that night, as they did.  He knew where they had been for the last forty-eight hours, and why Jack Bailey had not returned with him.  It seemed to me that without fuller confidence from both the children—­they are always children to me—­I should never be able to learn anything.

As I was finally getting ready for bed, Halsey came up-stairs and knocked at my door.  When I had got into a negligee—­I used to say wrapper before Gertrude came back from school—­I let him in.  He stood in the doorway a moment, and then he went into agonies of silent mirth.  I sat down on the side of the bed and waited in severe silence for him to stop, but he only seemed to grow worse.

When he had recovered he took me by the elbow and pulled me in front of the mirror.