Mr. Marlow: "On the night in question three incidents occurred of which we have positive knowledge. The first was the summary discharge by the murdered man of his clerk, Mr. Abel Death, whose singular disappearance has yet to be accounted for; the second was the visit of Lady Wharton to Mr. Samuel Boyd, and her depositing with him certain articles of jewellery which her ladyship will be called upon to identify; the third, the visit of Reginald Boyd to his father under the circumstances I have mentioned. I name these incidents in the order of their occurrence. From the first discovery of the murder suspicion pointed to Reginald Boyd as its probable perpetrator, but the disclosures made up to a certain point of the inquiry in the Coroner's Court were not considered sufficiently conclusive by the police to warrant his arrest. But he was kept under observation. Towards the conclusion of the second day of the inquiry an important witness came forward in the person of Dr. Pye, a gentleman who, we understand, has devoted his life to scientific pursuits. This gentleman resides in Shore Street, a street running parallel to Catchpole Square. The windows at the back of Dr. Pye's house directly face the front of the house occupied by Mr. Samuel Boyd. It has been his habit for years to keep up late at night for the purpose of making scientific experiments, and on the night of Friday the 1st of March he was so employed. At three o'clock on that night--that is to say, on the morning of Saturday, the 2nd--he was standing at the window of the room in which he was at work, when his attention was attracted by an unusual movement at the door of Samuel Boyd's house. It will be necessary to bear in mind that Catchpole Square is a _cul de sac_, and that it is very rarely indeed that any person enters there, and none, unless it be an entire stranger, with the intention of passing through. The entrance to the Square is through a hooded passage bearing the ominous name of Deadman's Court. As I have told you, Dr. Pye was standing at the window--as he will tell you aimlessly, and as I submit in the abstracted mood habitual to students after some hours of secluded work--when he dimly observed the opening of the street door. An incident so unusual and suspicious made a strong impression upon him, and for the purpose of ascertaining the cause he brought forward an ingenious contrivance of his own invention by means of which he is enabled to throw a flashlight a considerable distance upon any desired spot, while the operator remains in shadow. The flashlight revealed the figure of a man standing at the door in an attitude of fear; Dr. Pye distinguished quite clearly the features of this man, who at that time was a stranger to him. The man remained at the door in his fear-struck attitude for several moments; then, the flashlight extinguished, Dr. Pye observed the shadow of a man--the night was dark, and he could distinguish no more than the shadow--slink