was out of it!  Yet, somehow I don’t think this is a very good explanation, when I remember the demure look the thing seemed to have when I saw it lying on the floor of the chancel.  Only I know this, that when I had replaced the dagger I had quite a touch of nerves and I stopped only to pick up my lantern from where I had placed it whilst I examined the weapon, after which I went down the quiet aisle at a pretty quick walk, and so got out of the place.

“That the nerve tension had been considerable, I realized, when I had locked the door behind me.  I felt no inclination now to think of old Sir Alfred as a hypochondriac because he had taken such hyperseeming precautions regarding the Chapel.  I had a sudden wonder as to whether he might not have some knowledge of a long prior tragedy in which the dagger had been concerned.

“I returned to my room, washed, shaved and dressed, after which I read awhile.  Then I went downstairs and got the acting butler to give me some sandwiches and a cup of coffee.

“Half an hour later I was heading for Burtontree, as hard as I could walk; for a sudden idea had come to me, which I was anxious to test.  I reached the town a little before eight thirty, and found the local photographer with his shutters still up.  I did not wait, but knocked until he appeared with his coat off, evidently in the act of dealing with his breakfast.  In a few words I made clear that I wanted the use of his dark room immediately, and this he at once placed at my disposal.

“I had brought with me the slide which contained the plate that I had used with the flashlight, and as soon as I was ready I set to work to develop.  Yet, it was not the plate which I had exposed, that I first put into the solution, but the second plate, which had been ready in the camera during all the time of my waiting in the darkness.  You see, the lens had been uncapped all that while, so that the whole chancel had been, as it were, under observation.

“You all know something of my experiments in ‘Lightless Photography,’ that is, appreciating light.  It was X-ray work that started me in that direction.  Yet, you must understand, though I was attempting to develop this ‘unexposed’ plate, I had no definite idea of results—­nothing more than a vague hope that it might show me something.

“Yet, because of the possibilities, it was with the most intense and absorbing interest that I watched the plate under the action of the developer.  Presently I saw a faint smudge of black appear in the upper part, and after that others, indistinct and wavering of outline.  I held the negative up to the light.  The marks were rather small, and were almost entirely confined to one end of the plate, but as I have said, lacked definiteness.  Yet, such as they were, they were sufficient to make me very excited and I shoved the thing quickly back into the solution.