“That is possible,” said Thorndyke:  “though I don’t quite see how it would have happened.  I notice that his pockets seem to have been emptied—­no, wait; here is something in the waistcoat pocket.”

He drew out a shabby, pigskin card-case and a stump of lead pencil, at which latter he looked with what seemed to me much more interest than was deserved by so commonplace an object.

“The cards, you observe,” said he, “are printed from type, not from a plate.  I would note that fact.  And tell me what you make of that.”

He handed me the pencil, which I examined with concentrated attention, helping myself even with the lamp and my pocket lens.  But even with these aids I failed to discover anything unusual in its appearance.  Thorndyke watched me with a mischievous smile, and, when I had finished, inquired: 

“Well; what is it?”

“Confound you!” I exclaimed.  “It’s a pencil.  Any fool can see that, and this particular fool can’t see any more.  It’s a wretched stump of a pencil, villainously cut to an abominably bad point.  It is coloured dark red on the outside and was stamped with some name that began with C—­O—­Co-operative Stores, perhaps.”

“Now, my dear Jervis,” Thorndyke protested, “don’t begin by confusing speculation with fact.  The letters which remain are C—­O.  Note that fact and find out what pencils there are which have inscriptions beginning with those letters.  I am not going to help you, because you can easily do this for yourself.  And it will be good discipline even if the fact turns out to mean nothing.”

At this moment he stepped back suddenly, and, looking down at the floor, said: 

“Give me the lamp, Jervis, I’ve trodden on something that felt like glass.”

I brought the lamp to the place where he had been standing, close by the bed, and we both knelt on the floor, throwing the light of the lamp on the bare and dusty boards.  Under the bed, just within reach of the foot of a person standing close by, was a little patch of fragments of glass.  Thorndyke produced a piece of paper from his pocket and delicately swept the little fragments on to it, remarking: 

“By the look of things, I am not the first person who has trodden on that object, whatever it is.  Do you mind holding the lamp while I inspect the remains?”

I took the lamp and held it over the paper while he examined the little heap of glass through his lens.

“Well,” I asked.  “What have you found?”

“That is what I am asking myself,” he replied.  “As far as I can judge by the appearance of these fragments, they appear to be portions of a small watch-glass.  I wish there were some larger pieces.”

“Perhaps there are,” said I.  “Let us look about the floor under the bed.”

We resumed our groping about the dirty floor, throwing the light of the lamp on one spot after another.  Presently, as we moved the lamp about, its light fell on a small glass bead, which I instantly picked up and exhibited to Thorndyke.