Here was a case in point.  I had myself seen all that he had seen, and, indeed, much more; for I had looked on the very people and witnessed their actions, whereas he had never set eyes on any of them.  I had examined the little handful of rubbish that he had gathered up so carefully, and would have flung it back under the grate without a qualm.  Not a glimmer of light had I perceived in the cloud of mystery, nor even a hint of the direction in which to seek enlightenment.  And yet Thorndyke had, in some incomprehensible manner, contrived to piece together facts that I had probably not even observed, and that so completely that he had already, in these few days, narrowed down the field of inquiry to quite a small area.

From these reflections I returned to the objects on the table.  The spectacles, as things of which I had some expert knowledge, were not so profound a mystery to me.  A pair of spectacles might easily afford good evidence for identification; that I perceived clearly enough.  Not a ready-made pair, picked up casually at a shop, but a pair constructed by a skilled optician to remedy a particular defect of vision and to fit a particular face.  And such were the spectacles before me.  The build of the frames was peculiar; the existence of a cylindrical lens—­which I could easily make out from the remaining fragments—­showed that one glass had been cut to a prescribed shape and almost certainly ground to a particular formula, and also that the distance between centres must have been carefully secured.  Hence these spectacles had an individual character.  But it was manifestly impossible to inquire of all the spectacle-makers in Europe—­for the glasses were not necessarily made in England.  As confirmation the spectacles might be valuable; as a starting-point they were of no use at all.

From the spectacles I turned to the pieces of reed.  These were what had given Thorndyke his start.  Would they give me a leading hint too?  I looked at them and wondered what it was that they had told Thorndyke.  The little fragment of the red paper label had a dark-brown or thin black border ornamented with a fret-pattern, and on it I detected a couple of tiny points of gold like the dust from leaf-gilding.  But I learned nothing from that.  Then the shorter piece of reed was artificially hollowed to fit on the longer piece.  Apparently it formed a protective sheath or cap.  But what did it protect?  Presumably a point or edge of some kind.  Could this be a pocket-knife of any sort, such as a small stencil-knife?  No; the material was too fragile for a knife-handle.  It could not be an etching-needle for the same reason; and it was not a surgical appliance—­at least it was not like any surgical instrument that was known to me.