Half raising himself, with all his strength he caught the other a terrible blow in the pit of the stomach. The baron gave a gurgle and lay stunned and unconscious.
"That comes of having a deficient sense of logic, my friend," said Lupin. "I offered you half your money. Now I'll give you none at all ... provided I know where to find any of it. For that's the main thing. Where has the beggar hidden his dust? In the safe? By George, it'll be a tough job! Luckily, I have all the night before me...."
He began to feel in the baron's pockets, came upon a bunch of keys, first made sure that the portmanteau behind the curtain held no papers or jewels, and then went to the safe.
But, at that moment, he stopped short: he heard a noise somewhere. The servants? Impossible. Their attics were on the top floor. He listened. The noise came from below. And, suddenly, he understood: the detectives, who had heard the two shots, were banging at the front door, as was their duty, without waiting for daybreak. Then an electric bell rang, which Lupin recognized as that in the hall:
"By Jupiter!" he said. "Pretty work! Here are these jokers coming ... and just as we were about to gather the fruits of our laborious efforts! Tut, tut, Lupin, keep cool! What's expected of you? To open a safe, of which you don't know the secret, in thirty seconds. That's a mere trifle to lose your head about! Come, all you have to do is to discover the secret! How many letters are there in the word? Four?"
He went on thinking, while talking and listening to the noise outside. He double-locked the door of the outer room and then came back to the safe:
"Four ciphers.... Four letters ... four letters.... Who can lend me a hand?... Who can give me just a tiny hint?... Who? Why, Lavernoux, of course! That good Lavernoux, seeing that he took the trouble to indulge in optical telegraphy at the risk of his life.... Lord, what a fool I am!... Why, of course, why, of course, that's it!... By Jove, this is too exciting!... Lupin, you must count ten and suppress that distracted beating of your heart. If not, it means bad work."
He counted ten and, now quite calm, knelt in front of the safe. He turned the four knobs with careful attention. Next, he examined the bunch of keys, selected one of them, then another, and attempted, in vain, to insert them in the lock:
"There's luck in odd numbers," he muttered, trying a third key. "Victory! This is the right one! Open Sesame, good old Sesame, open!"
The lock turned. The door moved on its hinges. Lupin pulled it to him, after taking out the bunch of keys: