do you mean by that?'
'I drive a closed cab, sir. When he got in he was a smooth-faced gentleman; when he got out he wore a short black beard.'
'Was he a Frenchman?'
'No, sir; he was a foreigner, either English or American.'
'Was he carrying a box?'
'No, sir; he held in his hand a small leather bag.'
'Where did he tell you to drive?'
'He told me to follow the cab in front, which had just driven off very rapidly towards the Madeleine. In fact, I heard the man, such as you describe, order the other cabman to drive to the Madeleine. I had come alongside the curb when this man held up his hand for a cab, but the open cab cut in ahead of me. Just then my passenger stepped up and said in French, but with a foreign accent: "Follow that cab wherever it goes."'
I turned with some indignation to my inefficient spy.
'You told me,' I said, 'that the American had gone down a side street. Yet he evidently met a second man, obtained from him the handbag, turned back, and got into the closed cab directly behind you.'
'Well, sir,' stammered the spy, 'I could not look in two directions at the same time. The American certainly went down the side street, but of course I watched the cab which contained the jewels.'
'And you saw nothing of the closed cab right at your elbow?'
'The boulevard was full of cabs, sir, and the pavement crowded with passers-by, as it always is at that hour of the day, and I have only two eyes in my head.'
'I am glad to know you had that many, for I was beginning to think you were blind.'
Although I said this, I knew in my heart it was useless to censure the poor wretch, for the fault was entirely my own in not sending two men, and in failing to guess the possibility of the jewels and their owner being separated. Besides, here was a clue to my hand at last, and no time must be lost in following it up. So I continued my interrogation of the cabman.
'The other cab was an open vehicle, you say?'
'Yes, sir.'
'You succeeded in following it?'
'Oh, yes, sir. At the Madeleine the man in front redirected the coachman, who turned to the left and drove to the Place de la Concorde, then up the Champs-Elysées to the Arch and so down the Avenue de la Grande Armée, and the Avenue de Neuilly, to the Pont de Neuilly, where it came to a standstill. My fare got out, and I saw he now wore a short black beard, which he had evidently put on inside the cab. He gave me a ten-franc piece, which was very satisfactory.
'And the fare you were following? What did he do?'
'He also stepped out, paid the cabman, went down the bank of the river and got on board a steam launch that seemed to be waiting for him.'
'Did he look behind, or appear to know that he was being followed?'
'No, sir.'
'And your fare?'
'He ran after the first man, and also went aboard the steam launch, which instantly started down the river.'
'And that was the last you saw of them?'
'Yes, sir.'
'At what time did you reach the Pont de Neuilly?'
'I do not know, sir; I was compelled to drive rather fast, but the distance is seven to eight kilometres.'
'You would do it under the hour?'
'But certainly, under the hour.'
'Then you must have reached Neuilly bridge about four o'clock?'
'It is very likely, sir.'
The plan of the tall American was now perfectly clear to me, and it comprised nothing that was contrary to law. He had evidently placed his luggage on board the steam launch in the morning. The handbag had contained various materials which would enable him to disguise himself, and this bag he had probably left in some shop down the side street, or else someone was waiting with it for him. The giving of the treasure to another man was not so risky as it had at first appeared, because he instantly followed that man, who was probably his confidential servant. Despite the windings of the river there was ample time for the launch to reach Havre before the American steamer sailed on Saturday morning. I surmised it was his intention to come alongside the steamer before she left her berth in Havre harbour, and thus transfer himself and his belongings unperceived by anyone on watch at the land side of the liner.
All this, of course, was perfectly justifiable, and seemed, in truth, merely a well-laid scheme for escaping observation. His only danger of being tracked was when he got into the cab. Once away from the neighbourhood of the Boulevard des Italiens he was reasonably sure to evade pursuit, and the five minutes which his friend with the pistols had won for him afforded just the time he needed to get so far as the Place Madeleine, and after that everything was easy. Yet, if it had not been for those five minutes secured by coercion, I should not have found the slightest excuse for arresting him. But he was accessory after the act in that piece of illegality—in fact, it was absolutely certain that he had been accessory before the act, and guilty of conspiracy with the man who had presented firearms to the auctioneer's audience, and who had interfered with an officer in the discharge of his duty by threatening me and my men. So I was now legally in the right if I arrested every person on board that steam launch.
With a map of the river before me I proceeded to make some calculations. It was now nearly ten o'clock at night. The launch had had six hours in which to travel at its utmost speed. It was doubtful if so small a vessel could make ten miles an hour, even with the current in its favour, which is rather sluggish because of the locks and the level country. Sixty miles would place her beyond Meulan, which is fifty-eight miles from the Pont Royal, and, of course, a lesser distance from the Pont de Neuilly. But the navigation of the river is difficult at all times, and almost impossible after dark. There were chances of the boat running aground, and then there was the inevitable delay at the locks. So I estimated that the launch could not yet have reached Meulan, which was less than twenty-five miles from Paris by rail. Looking up the timetable I saw there were still two trains to Meulan, the next at 10.25, which reached Meulan at 11.40. I therefore had time to reach St. Lazare station, and accomplish some telegraphing before the train left.
With three of my assistants I got into a cab and drove to the station. On arrival I sent one of my men to hold the train while I went into the telegraph office, cleared the wires, and got into communication with the lock master at Meulan. He replied that no steam launch had passed down since an hour before sunset. I then instructed him to allow the yacht to enter the lock, close the upper gate, let half of the water out, and hold the vessel there until I came. I also ordered the local Meulan police to send enough men to the lock to enforce this command. Lastly, I sent messages all along the river asking the police to report to me on the train the passage of the steam launch.
The 10.25 is a slow train, stopping at every station. However, every drawback has its compensation, and these stoppages enabled me to receive and to send telegraphic messages. I was quite well aware that I might be on a fool's errand in going to Meulan. The yacht could have put about before it had steamed a mile, and so returned back to Paris. There had been no time to learn whether this was so or not if I was to catch the 10.25. Also,
