The head of the conspiracy, Artois, could not be reached. Expected on the French coast, he had not come. But his cousin, the Duke d’Enghien was at Ettenheim, close to the French border. What was he doing there? He had borne arms against France, a crime which under the law of nations is treason, and which under the law of all lands is punishable with death. By French law, existing at the time, he had forfeited his life as a traitor. He was in the pay of England, the enemy of France. He was closely related by blood and by interest to the two brothers, Provence and Artois, who were making desperate efforts to recover the crown for the Bourbon family. What was the young Bourbon duke doing so near to the French border at this particular time? Royalist authors say that he was there to enjoy the pleasures of the chase; also to enjoy the society of the Princess de Rohan, to whom they now say, without evidence, that he was secretly married. Sir Walter Scott, a most unfriendly witness for Napoleon, admits that d’Enghien “fixed himself on the frontier for the purpose of being ready to put himself at the head of the royalists in East France, or Paris itself.” That he was on the Rhine awaiting some event, some change in France in which he would have “a part to play,” was confessed, and cannot be denied. What was the movement at whose head he was waiting to place himself? What other plan did the royalists have in progress at the time other than the Georges-Pichegru plot? If d’Enghien was waiting on the Rhine until they should have dealt the blow in Paris, was he not an accomplice, a principal in the second degree? It does not matter whether he knew the details of the Georges-Pichegru conspiracy or not. If he had been instructed to hold himself in readiness on the French frontier to enter the country and “act a part” therein, his common sense told him that a plot was on foot, and if he did not wish to be treated as an accomplice, he should not have acted as one. The cowardly d’Artois had not left London, and the Duke d’Enghien was to enter France as representative of the Bourbon family after the First Consul should have been killed. The rule in law and equity is that where one is put upon notice of a transaction, he is to be held as knowing all that he could have learned by reasonable inquiry. The instructions issued to d’Enghien put him upon notice that something unusual was in progress, that it concerned him, and that he had a part to play. Prudent inquiry made by him of his Bourbon relatives in London would have put him in possession of the facts. This inquiry he either made or he did not: if he made it, he learned of the plot; if he did not make it, his was the negligence of being ignorant of the plan in which he was to “act a part.”