obviously some kind of password.

Inside the doorway the passage gleamed as if it were lined with a
network of steel. On a second glance, Syme saw that the glittering
pattern was really made up of ranks and ranks of rifles and
revolvers, closely packed or interlocked.

"I must ask you to forgive me all these formalities," said Gregory;
"we have to be very strict here."

"Oh, don't apologise," said Syme. "I know your passion for law and
order," and he stepped into the passage lined with the steel
weapons. With his long, fair hair and rather foppish frock-coat, he
looked a singularly frail and fanciful figure as he walked down
that shining avenue of death.

They passed through several such passages, and came out at last
into a queer steel chamber with curved walls, almost spherical in
shape, but presenting, with its tiers of benches, something of the
appearance of a scientific lecture-theatre. There were no rifles or
pistols in this apartment, but round the walls of it were hung more
dubious and dreadful shapes, things that looked like the bulbs of
iron plants, or the eggs of iron birds. They were bombs, and the
very room itself seemed like the inside of a bomb. Syme knocked his
cigar ash off against the wall, and went in.

"And now, my dear Mr. Syme," said Gregory, throwing himself in an
expansive manner on the bench under the largest bomb, "now we are
quite cosy, so let us talk properly. Now no human words can give
you any notion of why I brought you here. It was one of those quite