knitted stockings, one over the other. Now
look at the other footprints; there is a double track, you see, one set
coming from the sea and one going towards it. As the man (who was
bow-legged and turned his toes in) has trodden in his own footprints, it
is obvious that he came from the sea, and returned to it. But observe
the difference in the two sets of prints; the returning ones are much
deeper than the others, and the stride much shorter. Evidently he was
carrying something when he returned, and that something was very heavy.
Moreover, we can see, by the greater depth of the toe impressions, that
he was stooping forward as he walked, and so probably carried the weight
on his back. Is that quite clear?"

"Perfectly," I replied. "But how do you arrive at the interval of time
between the visits of the two men?"

"That also is quite simple. The tide is now about halfway out; it is
thus about three hours since high water. Now, the fisherman walked just
about the neap-tide, high-water mark, sometimes above it and sometimes
below. But none of his footprints have been obliterated; therefore he
passed after high water--that is, less than three hours ago; and since
his footprints are all equally distinct, he could not have passed when
the sand was very wet. Therefore he probably passed less than an hour
ago. The other man's footprints, on the other hand, reach only to the
neap-tide, high-water mark, where they end abruptly. The sea has washed
over the remainder of the tracks and obliterated them. Therefore he
passed not less than three hours and not more than four days
ago--probably within twenty-four hours."

As Thorndyke concluded his demonstration the sound of voices was borne
to us from above, mingled with the tramping of feet, and immediately
afterwards a very singular party appeared at the head of the gap
descending towards the shore. First came a short burly fisherman clad in
oilskins and sou'-wester, clumping along awkwardly in his great
sea-boots, then the local police-sergeant in company with my
professional rival Dr. Burrows, while the rear of the procession was
brought up by two constables carrying a stretcher. As he reached the
bottom of the gap the fisherman, who was evidently acting as guide,
turned along the shore, retracing his own tracks, and the procession
followed in his wake.

"A surgeon, a stretcher, two constables, and a police-sergeant,"
observed Thorndyke. "What does that suggest to your mind, Je