"A few words," he said to himself, "a few words from that incredible person known as Arsène Lupin, will clear up the mystery. It will not take him long. He will be gone in an hour. Will he take the secret of the gold with him, I wonder? Will he solve the secret of the golden triangle for me? And how will he keep the gold for himself? How will he take it away?" A motor-car arrived from the direction of the Trocadéro. It slowed down and stopped beside the pavement. It must be Don Luis, thought Patrice. But, to his great surprise, he recognized M. Masseron, who opened the door and came towards him with outstretched hand: "Well, captain, how are you? I'm punctual for the appointment, am I not? But, I say, have you been wounded in the head again?" "Yes, an accident of no importance," replied Patrice. "But what appointment are you speaking of?" "Why, the one you gave me, of course!" "I gave you no appointment." "Oh, I say!" said M. Masseron. "What does this mean? Why, here's the note they brought me at the police-office: 'Captain Belval's compliments to M. Masseron. The problem of the golden triangle is solved. The eighteen hundred bags are at his disposal. Will he please come to the Quai de Passy, at six o'clock, with full powers from the government to accept the conditions of delivery. It would be well if he brought with him twenty powerful detectives, of whom half should be posted a hundred yards on one side of Essarès' property and the other half on the other.' There you are. Is it clear?" "Perfectly clear," said Patrice, "but I never sent you that note." "Who sent it then?" "An extraordinary man who deciphered all those problems like so many children's riddles and who certainly will be here himself to bring you the solution." "What's his name?" "I sha'n't say." "Oh, I don't know about that! Secrets are hard to keep in war-time." "Very easy, on the contrary, sir," said a voice behind M. Masseron. "All you need do is to make up your mind to it." M. Masseron and Patrice turned round and saw a gentleman dressed in a long, black overcoat, cut like a frock-coat, and a tall collar which gave him a look of an English clergyman. "This is the friend I was speaking of," said Patrice, though he had some difficulty in recognizing Don Luis. "He twice saved my life and also that of the lady whom I am going to marry. I will answer for him in every respect." M. Masseron bowed; and Don Luis at once began, speaking with a slight accent: