'Then why are you standing here like a fool?'
'I followed him this far, when a man came up the Rue Michodière, and without a word the American handed him the jewel-box, turning instantly down the street up which the other had come. The other jumped into a cab, and drove towards the Place de l'Opéra.'
'And what did you do? Stood here like a post, I suppose?'
'I didn't know what to do, sir. It all happened in a moment.'
'Why didn't you follow the cab?'
'I didn't know which to follow, sir, and the cab was gone instantly while I watched the American.'
'What was its number?'
'I don't know, sir.'
'You clod! Why didn't you call one of our men, whoever was nearest, and leave him to shadow the American while you followed the cab?'
'I did shout to the nearest man, sir, but he said you told him to stay there and watch the English lord, and even before he had spoken both American and cabman were out of sight.'
'Was the man to whom he gave the box an American also?'
'No, sir, he was French.'
'How do you know?'
'By his appearance and the words he spoke.'
'I thought you said he didn't speak.'
'He did not speak to the American, sir, but he said to the cabman, "Drive to the Madeleine as quickly as you can."'
'Describe the man.'
'He was a head shorter than the American, wore a black beard and moustache rather neatly trimmed, and seemed to be a superior sort of artisan.'
'You did not take the number of the cab. Should you know the cabman if you saw him again?'
'Yes, sir, I think so.'
Taking this fellow with me I returned to the now nearly empty auction room and there gathered all my men about me. Each in his notebook took down particulars of the cabman and his passenger from the lips of my incompetent spy; next I dictated a full description of the two Americans, then scattered my men to the various railway stations of the lines leading out of Paris, with orders to make inquiries of the police on duty there, and to arrest one or more of the four persons described should they be so fortunate as to find any of them.
I now learned how the rogue with the pistols vanished so completely as he did. My subordinate in the auction room had speedily solved the mystery. To the left of the main entrance of the auction room was a door that gave private access to the rear of the premises. As the attendant in charge confessed when questioned, he had been bribed by the American earlier in the day to leave this side door open and to allow the man to escape by the goods entrance. Thus the ruffian did not appear on the boulevard at all, and so had not been observed by any of my men.
Taking my futile spy with me I returned to my own office, and sent an order throughout the city that every cabman who had been in the Boulevard des Italiens between half-past two and half-past three that afternoon, should report immediately to me. The examination of these men proved a very tedious business indeed, but whatever other countries may say of us, we French are patient, and if the haystack is searched long enough, the needle will be found. I did not discover the needle I was looking for, but I came upon one quite as important, if not more so.
It was nearly ten o'clock at night when a cabman answered my oft-repeated questions in the affirmative.
'Did you take up a passenger a few minutes past three o'clock on the Boulevard des Italiens, near the Crédit-Lyonnais? Had he a short black beard? Did he carry a small box in his hand and order you to drive to the Madeleine?'
The cabman seemed puzzled.
'He wore a short black beard when he got out of the cab,' he replied.
'What 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