“I gather that at about a quarter to two on the morning of the crime, a man (who had, on the previous day visited the house to obtain the tress of hair and oil the locks) entered the house by means of a latchkey.  We can fix the time by the fact that it rained on that morning from half-past one to a quarter to two, this being the only rain that has fallen for a fortnight, and the murder was committed at about two o’clock.  The man lit a wax match in the hall and another halfway up the stairs.  He found the bedroom door locked, and turned the key from outside with a bent wire.  He entered, lit the candle, placed the box and hassock, murdered his victim, washed his hands and knife, took the candle-end from the socket and went downstairs, where he blew out the candle and dropped it into the tray.

“The next clue is furnished by the sand on the pillow.  I took a little of it, and examined it under the microscope, when it turned out to be deep-sea sand from the Eastern Mediterranean.  It was full of the minute shells called ‘Foraminifera,’ and as one of these happened to belong to a species which is found only in the Levant, I was able to fix the locality.”

“But this is very remarkable,” said the coroner.  “How on earth could deep-sea sand have got on to this woman’s pillow?”

“The explanation,” replied Thorndyke, “is really quite simple.  Sand of this kind is contained in considerable quantities in Turkey sponges.  The warehouses in which the sponges are unpacked are often strewn with it ankle deep; the men who unpack the cases become dusted over with it, their clothes saturated and their pockets filled with it.  If such a person, with his clothes and pockets full of sand, had committed this murder, it is pretty certain that in leaning over the head of the bed in a partly inverted position he would have let fall a certain quantity of the sand from his pockets and the interstices of his clothing.  Now, as soon as I had examined this sand and ascertained its nature, I sent a message to Mr. Goldstein asking him for a list of the persons who were acquainted with the deceased, with their addresses and occupations.  He sent me the list by return, and among the persons mentioned was a man who was engaged as a packer in a wholesale sponge warehouse in the Minories.  I further ascertained that the new season’s crop of Turkey sponges had arrived a few days before the murder.

“The question that now arose was, whether this sponge-packer was the person whose fingerprints I had found on the candle-end.  To settle this point, I prepared two mounted photographs, and having contrived to meet the man at his door on his return from work, I induced him to look at them and compare them.  He took them from me, holding each one between a forefinger and thumb.  When he returned them to me, I took them home and carefully dusted each on both sides with a certain surgical dusting-powder.  The powder adhered to the places where his fingers and thumbs had pressed against the photographs, showing the fingerprints very distinctly.  Those of the right hand were identical with the prints on the candle, as you will see if you compare them with the cast.”  He produced from the box the photograph of the Yiddish lettering, on the black margin of which there now stood out with startling distinctness a yellowish-white print of a thumb.