“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!”