“And for the same reason even now,” I said, “you wouldn’t tell the police?”

“Let sleeping dogs lie,” Jack answered, in the same words as Dr. Marten.  “Why rake up this whole matter?  It’s finished for ever now, and nobody but yourself is ever likely to reopen it.  If we both told our tale, we might run a great risk of being seriously misinterpreted.  You know it’s true; so do I:  but who else would believe us?  No man’s bound to criminate himself.  You shot him to save my life, at the very moment when you first learned all his cruelty and his vileness.  The rest of the world could never be made to understand all that.  They’d say to the end, as it looks on the surface, ’She shot her father to save her lover.’”

“You’re right,” I said slowly.  “I shall let this thing rest.  But the photographs, Jack—­the apparatus—­the affair of the inquest?”

“That was all very simple,” Jack answered.  “For a day or two, of course, I was in a frantic state of mind for fear you should be suspected, or the revolver should betray you.  But though I saw the electric sparks, of course, I knew nothing about the photographs.  I wasn’t even aware that the apparatus took negatives automatically.  And I was so full of the terrible reports in the newspapers about your sudden loss of health, that I could think of nothing else—­least of all my own safety.  As good luck would have it, however, the clergyman at Wrode, who knew the Wilsons, happened to speak to me of the murder—­all England called it the murder and talked of nothing else for at least a fortnight,—­and in the course of conversation he mentioned this apparatus of Mr. Callingham’s construction.  ‘What a pity,’ he said, ’there didn’t happen to be one of them in the library at the time!  If it was focussed towards the persons, and had been set on by the victim, it would have photographed the whole scene the murder, the murderer.’

“That hint revealed much to me.  As he spoke, I remembered suddenly about those mysterious flashes when you burst all at once on my sight from behind the screen.  Till that moment, I thought of them only as some result of your too suddenly turning off the electric current.  But then, it came home to me in a second that Mr. Callingham must have set out his apparatus all ready for experimenting—­that the electric apparatus was there to put it in working order.  The button you turned must not only have stopped the current that nailed me writhing to the spot:  it must also have set working the automatic photographic camera!

“That thought, as you may imagine, filled me with speechless alarm:  for I remembered then that one of the flashes broke upon us at the exact moment when you fired the pistol.  Such a possibility was horrible to contemplate.  The photographs by themselves could give no clue to our conversation or to the events that compelled you, almost against your own will, to fire that fatal shot.  If they were found by the police, all would be up with both of us.  They might hang me if they liked:  except for Elsie’s sake, I didn’t mind much about that:  but for your safety, come what might, I felt I must manage to get hold of them or to destroy them.