What is the value of this pamphlet? Nothing, you will tell me, and we must attach no credit to it. And this is the impression which I myself would have carried away, if it had not occurred to me to open Cæsar’s _Commentaries_ at the chapter given. What was my astonishment when I came upon the phrase quoted in the little book before me! And it was the same thing with the Treaty of Saint-Clair-sur-Epte, with the _Saxon Chronicle_, with the examination of Joan of Arc, in short, with all that I have been able to verify up to the present. Lastly, there is an even more precise fact related by the author of the pamphlet of 1815. During the French campaign, he being then an officer under Napoleon, his horse dropped dead, one evening, and he rang at the door of a castle where he was received by an old knight of St. Louis. And, in the course of conversation with the old man, he learnt that this castle, standing on the bank of the Creuse, was called the Château de l’Aiguille, that it had been built and christened by Louis XIV., and that, by his express order, it was adorned with turrets and with a spire which represented the Needle. As its date it bore, it must still bear, the figure 1680. 1680! One year after the publication of the book and the imprisonment of the Iron Mask! Everything was now explained: Louis XIV., foreseeing that the secret might be noised abroad, had built and named that castle so as to offer the quidnuncs a natural explanation of the ancient mystery. The Hollow Needle! A castle with pointed bell-turrets standing on the bank of the Creuse and belonging to the King. People would at once think that they had the key to the riddle and all enquiries would cease. The calculation was just, seeing that, more than two centuries later, M. Beautrelet fell into the trap. And this, Sir, is what I was leading up to in writing this letter. If Lupin, under the name of Anfredi, rented from M. Valméras the Château de l’Aiguille on the bank of the Creuse; if, admitting the success of the inevitable investigations of M. Beautrelet, he lodged his two prisoners there, it was because he admitted the success of the inevitable researches made by M. Beautrelet and because, with the object of obtaining the peace for which he had asked, he laid for M. Beautrelet precisely what we may call the historic trap of Louis XIV. And hence we come to this undeniable conclusion, that he, Lupin, by his unaided lights, without possessing any other facts than those which we possess, managed by means of the witchcraft of a really extraordinary genius, to decipher the undecipherable document; and that he, Lupin, the last heir of the Kings of France, knows the royal mystery of the Hollow Needle!