His readiness to murder on sight, however, made him a hero in the eyes of the riff-raff amongst the refugees, but the better class regarded him with distrust, and only put up with his "eccentricities" because the movement was short of men.
Amongst the colony at Egham there was an ex-naval officer of the name of Cournet. He had served his country well without enriching himself, and in character and disposition he was the reverse of Barthélemy, though Cournet, when provoked, was fierce and short-tempered. Still, he was, as a rule, polite and courteous, and he never originated a quarrel. The numerous revolutions in France had involved him as principal in no fewer than fourteen duels, and on every occasion he had hit his man. He was, therefore, a duellist of renown, and his reputation amongst the exiles was second to none. Barthélemy did not like this, and he resolved to depose Cournet from his leadership. To do this he had to force a duel upon the ex-officer, and one night at Egham, when Cournet was in his mildest humour, Barthélemy sprang to his feet and swore that the older man had grossly insulted him. In the circumstances he considered that Cournet ought to give him the "usual satisfaction one gentleman owes to another," and that meant a duel. But Barthélemy had forgotten one thing. He had challenged Cournet, who, accordingly, had the right to name the weapons. Now, Cournet was an expert with the pistol, and Barthélemy considered himself equally expert with the sword. As the challenged party, however, Cournet selected pistols, and Barthélemy had to abide by his choice.
The duel was fixed for the following day, and Barthélemy passed a night of terror. He saw himself an easy target for the ex-officer's pistol. In fact, he was perfectly certain that he was going to his death, and he did not want to die.
His partisans meanwhile published abroad amongst the French colony in London the news of the quarrel. It divided them into two camps, each clamorous for its champion's superiority. Bets were made as to the result, and at about the time the duel was to take place a crowd of refugees assembled in Leicester Square to hear the result, just as in the past the race for the Derby has caused crowds to assemble outside the offices of sporting papers to await the name of the winner.
The duel was to determine who was the unofficial leader of the Frenchmen driven into exile by Napoleon III. Cournet's friends, however, were never uneasy as to the result. They knew that their man would and must win, but, unfortunately for their principal, they forgot to take measures to prevent his opponent fighting unfairly. Barthélemy and his intimates actually tampered with his pistol, the weapon which had won for him fourteen similar contests. To lessen the chances of discovery they arranged that Cournet's pistol should go off the moment the trigger was touched, but not in the direction intended by its owner, and then when Barthélemy presented his weapon at his opponent it would misfire, proving that his pistol was defective too. The misfiring, however, would not forfeit his turn to shoot, and at the second attempt Barthélemy would have no difficulty in making the pistol do his bidding. These were the final arrangements, and they were carried out without a single flaw.
The duellists assembled on Englefield Green, and Cournet won the right to the first shot. To his astonishment and anger the charge in his pistol exploded, and the bullet went harmlessly into the air. The ex-officer was not, however, afraid. He stood rigid whilst Barthélemy levelled his weapon. It misfired, and Barthélemy had to devote a little time to setting it right. Then he remembered that the episode provided him with a chance for a theatrical display. In the best manner of the stage hero he offered to forego his shot if Cournet would consent to continue the duel with swords. The ex-officer instantly rejected the offer, pointing out that if Barthélemy missed he would be entitled to another shot, and then, he grimly added, he would not miss again. Barthélemy knew quite well that his opponent spoke only the barest truth, and without another moment's delay he levelled his pistol and shot Cournet dead.
It was murder, and murder of the most brutal and disgraceful type, but none of the seconds realized that. From first to last they had treated the English law against duelling with the utmost contempt, although they knew that according to the law of the land they were all murderers.
But they regarded themselves as a French colony owning the laws of France only, and, leaving poor Cournet lying stark and stiff, the seconds and Barthélemy went off to London with the intention of celebrating the victory in the Soho Cafés frequented by their fellow-countrymen. However, they were not at liberty for long, for at Waterloo Station they were met by detectives who took them into custody.
That was in 1852, not many years after the abolition of duelling in England, and, in the circumstances, it was considered wiser by the authorities to place Barthélemy only on trial for the murder of Cournet.
When the case came on at Kingston-on-Thames all the facts mentioned above were cited by the prosecution. It was clearly proved that the contest had not been a duel at all, but a cold-blooded murder on the part of the prisoner and his accomplices. The tampered pistols were produced, and the whole of Barthélemy's villainy laid bare; indeed, Counsel for the prosecution had the easiest of tasks. When the jury retired there was considerable surprise in Court, for no sensible person having heard the evidence should have wished for time to consider his verdict.