It's not funk," he said, "but, by Jove, this is an exciting business!
Each time that I'm on the point of catching him, it takes me like that
in the pit of the stomach. A dram of rum?"

"No."

"And if you drop behind?"

"That will mean that I'm dead."

"B-r-r-r-r! However, we'll see. And now, open, sesame! No danger of our
being observed, I suppose?"

"No. The Needle is not so high as the cliff, and, besides, there's a
bend in the ground where we are."

Beautrelet went to the wall and pressed upon the brick. The bolt was
released and the underground passage came in sight.

By the gleam of the lanterns which they lit, they saw that it was cut
in the shape of a vault and that both the vaulting and the floor itself
were entirely covered with bricks.

They walked for a few seconds and, suddenly, a staircase appeared.
Beautrelet counted forty-five brick steps, which the slow action of
many footsteps had worn away in the middle.

"Blow!" said Ganimard, holding his head and stopping suddenly, as
though he had knocked against something.

"What is it?"

"A door."

"Bother!" muttered Beautrelet, looking at it. "And not an easy one to
break down either. It's just a solid block of iron."

"We are done," said Ganimard. "There's not even a lock to it."

"Exactly. That's what gives me hope."

"Why?"

"A door is made to open; and, as this one has no lock, that means that
there is a secret way of opening it."

"And, as we don't know the secret--"

"I shall know it in a minute."

"How?"

"By means of the document. The fourth line has no other object but to
solve each difficulty as and when it crops up. And the solution is
comparatively easy, because it's not written with a view to throwing
searchers off the scent, but to assisting them."

"Comparatively easy! I don't agree with you," cried Ganimard, who had
unfolded the document. "The number 44 and a triangle with a dot in it:
that doesn't tell us much!"

"Yes, yes, it does! Look at the door. You see it's strengthened, at
each corner, with a triangular slab of iron; and the slabs are fixed
with big nails. Take the left-hand bottom slab and work the nail in the
corner: I'll lay ten to one we've hit the mark."

"You've lost your bet," said Ganimard, after trying.

"Then the figure 44 must mean--"

In a low voice, reflecting as he spoke, Beautrelet continued:

"Let me see--Ganimard and I are both standing on the bottom step of the
staircase--there are 45.