The thing looks like a miniature shell, and appears to be hollow." "It is hollow," said Thorndyke.

"You must have observed that, when I held it up to drain, the water trickled out through the hole at the pointed end." "Yes, I noticed that." "Now take it up and shake it." I did so and felt some heavy object rattle inside it.
"There is some loose body inside it," I said, "which fits it pretty closely, as it moves only in the long diameter." "Quite so; your description is excellent.

And now, what is the nature of this projectile ?" "I should say it is a miniature shell or explosive bullet." "Wrong!" said Thorndyke.

"A very natural inference, but a wrong one." "Then what is the thing ?" I demanded, my curiosity still further aroused.
"I will show you," he replied.

"It is something much more subtle than an explosive bullet--which would really be a rather crude appliance--admirably thought out and thoroughly well executed.