I whispered to the auctioneer, who bent his head to listen. He knew very well who I was, of course.

'You must not give up the necklace,' I began.

He shrugged his shoulders.

'I am under the orders of the official from the Ministry of the Interior. You must speak to him.'

'I shall not fail to do so,' I replied. 'Nevertheless, do not give up the box too readily.'

'I am helpless,' he protested with another shrug. 'I obey the orders of the Government.'

Seeing it was useless to parley further with the auctioneer, I set my wits to work to meet the new emergency. I felt convinced that the cheque would prove to be genuine, and that the fraud, wherever it lay, might not be disclosed in time to aid the authorities. My duty, therefore, was to make sure we lost sight neither of the buyer nor the thing bought. Of course I could not arrest the purchaser merely on suspicion; besides, it would make the Government the laughing-stock of the world if they sold a case of jewels and immediately placed the buyer in custody when they themselves had handed over his goods to him. Ridicule kills in France. A breath of laughter may blow a Government out of existence in Paris much more effectually than will a whiff of cannon smoke. My duty then was to give the Government full warning, and never lose sight of my man until he was clear of France; then my responsibility ended.

I took aside one of my own men in plain clothes and said to him,—

'You have seen the American who has bought the necklace?'

'Yes, sir.'

'Very well. Go outside quietly, and station yourself there. He is likely to emerge presently with the jewels in his possession. You are not to lose sight of either the man or the casket. I shall follow him and be close behind him as he emerges, and you are to shadow us. If he parts with the case you must be ready at a sign from me to follow either the man or the jewels. Do you understand?' 'Yes, sir,' he answered, and left the room.

It is ever the unforeseen that baffles us; it is easy to be wise after the event. I should have sent two men, and I have often thought since how admirable is the regulation of the Italian Government which sends out its policemen in pairs. Or I should have given my man power to call for help, but even as it was he did only half as well as I had a right to expect of him, and the blunder he committed by a moment's dull-witted hesitation—ah, well! there is no use of scolding. After all the result might have been the same.

Just as my man disappeared between the two folding doors the official from the Ministry of the Interior entered. I intercepted him about half-way on his journey from the door to the auctioneer.

'Possibly the cheque appears to be genuine,' I whispered to him.

'But certainly,' he replied pompously. He was an individual greatly impressed with his own importance; a kind of character with which it is always difficult to deal. Afterwards the Government asserted that this official had warned me, and the utterances of an empty-headed ass dressed in a little brief authority, as the English poet says, were looked upon as the epitome of wisdom.

'I advise you strongly not to hand over the necklace as has been requested,' I went on.

'Why?' he asked.

'Because I am convinced the bidder is a criminal.'

'If you have proof of that, arrest him.'

'I have no proof at the present moment, but I request you to delay the delivery of the goods.'

'That is absurd,' he cried impatiently. 'The necklace is his, not ours. The money has already been transferred to the account of the Government; we cannot retain the five million francs, and refuse to hand over to him what he has bought with them,' and so the man left me standing there, nonplussed and anxious. The eyes of everyone in the room had been turned on us during our brief conversation, and now the official proceeded ostentatiously up the room with a grand air of importance; then, with a bow and a flourish of the hand, he said, dramatically,—

'The jewels belong to Monsieur.'

The two Americans rose simultaneously, the taller holding out his hand while the auctioneer passed to him the case he had apparently paid so highly for. The American nonchalantly opened the box and for the first time the electric radiance of the jewels burst upon that audience, each member of which craned his neck to behold it. It seemed to me a most reckless thing to do. He examined the jewels minutely for a few moments, then snapped the lid shut again, and calmly put the box in his outside pocket, and I could not help noticing that the light overcoat he wore possessed pockets made extraordinarily large, as if on purpose for this very case. And now this amazing man walked serenely down the room past miscreants who joyfully would have cut his throat for even the smallest diamond in that conglomeration; yet he did not take the trouble to put his hand on the pocket which contained the case, or in any way attempt to protect it. The assemblage seemed stricken dumb by his audacity. His friend followed closely at his heels, and the tall man disappeared through the folding doors. Not so the other. He turned quickly, and whipped two revolvers out of his pockets, which he presented at the astonished crowd. There had been a movement on the part of every one to leave the room, but the sight of these deadly weapons confronting them made each one shrink into his place again.

The man with his back to the door spoke in a loud and domineering voice, asking the auctioneer to translate what he had to say into French and German; he spoke in English.

'These here shiners are valuable; they belong to my friend who has just gone out. Casting no reflections on the generality of people in this room, there are, nevertheless, half a dozen "crooks" among us whom my friend wishes to avoid. Now, no honest man here will object to giving the buyer of that there trinket five clear minutes in which to get away. It's only the "crooks" that can kick. I ask these five minutes as a favour, but if they are not granted I am going to take them as a right. Any man who moves will get shot.'

'I am an honest man,' I cried, 'and I object. I am chief detective of the French Government. Stand aside; the police will protect your friend.'

'Hold on, my son,' warned the American, turning one weapon directly upon me, while the other held a sort of roving commission, pointing all over the room. 'My friend is from New York and he distrusts the police as much as he does the grafters. You may be twenty detectives, but if you move before that clock strikes three, I'll bring you down, and don't you forget it.'

It is one thing to face death in a fierce struggle, but quite another to advance coldly upon it toward the muzzle of a pistol held so steadily that there could be no chance of escape. The gleam of determination in the man's eyes convinced me he meant what he said. I did not consider then, nor have I considered since, that the next five minutes, precious as they were, would be worth paying my life for. Apparently everyone else was of my opinion, for none moved hand or foot until the clock slowly struck three.

'Thank you, gentlemen,' said the American, as he vanished between the spring-doors. When I say vanished, I mean that word and no other, because my men outside saw nothing of this individual then or later. He vanished as if he had never existed, and it was some hours before we found how this had been accomplished.

I rushed out almost on his heels, as one might say, and hurriedly questioned my waiting men. They had all seen the tall American come out with the greatest leisure and stroll towards the west. As he was not the man any of them were looking for they paid no further attention to him, as, indeed, is the custom with our Parisian force. They have eyes for nothing but what they are sent to look for, and this trait has its drawbacks for their superiors.

I ran up the boulevard, my whole thought intent on the diamonds and their owner. I knew my subordinate in command of the men inside the hall would look after the scoundrel with the pistols. A short distance up I found the stupid fellow I had sent out, standing in a dazed manner at the corner of the Rue Michodière, gazing alternately down that short street and towards the Place de l'Opéra. The very fact that he was there furnished proof that he had failed.

'Where is the American?' I demanded.

'He went down this street, sir.'

'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 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.