tor has your name, I think?"

"He have, sir," replied the porter; and, pocketing his fee, he departed,
beaming.

"To return to the dagger," said Thorndyke, opening the drawer. "It was a
very peculiar one, as I have said, and as you will see from this model,
which is an exact duplicate." Here he exhibited Polton's production to
the astonished detective. "You see that it is extraordinarily slender,
and free from projections, and of unusual materials. You also see that
it was obviously not made by an ordinary dagger-maker; that, in spite of
the Italian word scrawled on it, there is plainly written all over it
'British mechanic.' The blade is made from a strip of common
three-quarter-inch tool steel; the hilt is turned from an aluminium rod;
and there is not a line of engraving on it that could not be produced in
a lathe by any engineer's apprentice. Even the boss at the top is
mechanical, for it is just like an ordinary hexagon nut. Then, notice
the dimensions, as shown on my drawing. The parts A and B, which just
project beyond the blade, are exactly similar in diameter--and such
exactness could hardly be accidental. They are each parts of a circle
having a diameter of 10.9 millimetres--a dimension which happens, by a
singular coincidence, to be exactly the calibre of the old Chassepot
rifle, specimens of which are now on sale at several shops in London.
Here is one, for instance."

He fetched the rifle that he had bought, from the corner in which it was
standing, and, lifting the dagger by its point, slipped the hilt into
the muzzle. When he let go, the dagger slid quietly down the barrel,
until its hilt appeared in the open breech.

"Good God!" exclaimed Marchmont. "You don't suggest that the dagger was
shot from a gun?"

"I do, indeed; and you now see the reason for the aluminium hilt--to
diminish the weight of the already heavy projectile--and also for this
hexagonal boss on the end?"

"No, I do not," said the inspector; "but I say that you are suggesting
an impossibility."

"Then," replied Thorndyke, "I must explain and demonstrate. To begin
with, this projectile had to travel point foremost; therefore it had to
be made to spin--and it certainly was spinning when it entered the body,
as the clothing and the wound showed us. Now, to make it spin, it had to
be fired from a rifled barrel; but as the hilt would not engage in the
rifling, it had to be fitted with something that would. That something
was evidently