As nearly as I could make out Kennedy had turned on the light in the lantern on his side of the table.  As he worked over the machine, which for the present served to distract Mrs. Willoughby’s attention from herself, he was asking her a series of questions.  From my position I could see that by the light of the machine he was recording both the questions and the answers, as well as the time registered to the fifth of a second by a stop-watch.  Mrs. Willoughby could not see what he was doing under the pretence of working over his little moving-picture machine.

He had at last finished the questioning.  Suddenly, without any warning, a picture began to play on the sheet.  I must say that I was startled myself.  It represented the jewelry counter at Trimble’s, and in it I could see Mrs. Willoughby herself in animated conversation with one of the clerks.  I looked intently, dividing my attention between the picture and the woman.  But so far as I could see there was nothing in this first film that incriminated either of them.

Kennedy started on the second without stopping.  It was practically the same as the first, only taken from a different angle.

He had scarcely run it half through when Dr. Guthrie opened the door.

“I think Mrs. Willoughby must have taken her hands off the metal domes,” he remarked; “I can get no record out here.”

I had turned when he opened the door, and now I caught a glimpse of Mrs. Willoughby standing, her hands pressed tightly to her head as if it were bursting, and swaying as if she would faint.  I do not know what the film was showing at this point, for Kennedy with a quick movement shut it off and sprang to her side.

“There, that will do, Mrs. Willoughby.  I see that you are not well,” he soothed.  “Doctor, a little something to quiet her nerves.  I think we can complete our work merely by comparing notes.  Call Mr. Willoughby, Walter.  There, sir, if you will take charge of your wife and perhaps take her for a turn or two in the fresh air, I think we can tell you in a few moments whether her condition is in any way serious or not.”

Mrs. Willoughby was on the verge of hysterics as her husband supported her out of the room.  The door had scarcely shut before Kennedy threw open a window and seemed to beckon into the darkness.  As if from nowhere, Donnelly and Bentley sprang no and were admitted.

Dr. Guthrie had now returned from the music-room, bearing a sheet of paper on which was traced a long irregular curve at various points on which marginal notes had been written hastily.

Kennedy leaped directly into the middle of things with his characteristic ardour.  “You recall,” he began, “that no one seemed to know just who took the jewels in both the cases you first reported?  ‘Seeing is believing,’ is an old saying, but in the face of such reports as you detectives gathered it is in a fair way to lose its force.  And you were not at fault, either, for modern psychology is proving by experiments that people do not see even a fraction of the things they confidently believe they see.