It is not to be supposed that Cryptography, as a serious thing, as the means of imparting important information, has gone out of use at the present day. It is still commonly practised in diplomacy; and there are individuals, even now, holding office in the eye of various foreign governments, whose real business is that of deciphering. We have already said that a peculiar mental action is called into play in the solution of cryptographical problems, at least in those of the higher order. Good cryptographists are rare indeed; and thus their services, although seldom required, are necessarily well requited. An instance of the modern employment of writing in cipher is mentioned in a work lately published by Messieurs Lea & Blanchard, of this city—“Sketches of Conspicuous Living Characters of France.” In a notice of Berryer, it is said that a letter being addressed by the Duchess de Berri to the legitimists of Paris, to inform them of her arrival, it was accompanied by a long note in cipher, the key of which she had forgotten to give. “The penetrating mind of Berryer,” says the biographer, “soon discovered it. It was this phrase substituted for the twenty-four letters of the alphabet—_Le gouvernement provisoire_.” The assertion that Berryer “soon discovered the key-phrase,” merely proves that the writer of these memoirs is entirely innocent of cryptographical knowledge. Monsieur B. no doubt ascertained the key-phrase; but it was merely to satisfy his curiosity, _after the riddle had been read_. He made no use of the key in deciphering. The lock was picked. In our notice of the book in question (published in the April number of this Magazine) we alluded to this subject thus— “The phrase ‘_Le gouvernement provisoire_’ is French, and the note in cipher was addressed to Frenchmen. The difficulty of deciphering may well be supposed much greater, had the key been in a foreign tongue; yet any one who will take the trouble may address us a note, in the same manner as here proposed; and the key-phrase may be either in French, Italian, Spanish, German, Latin, or Greek, (or in any of the dialects of these languages,) and we pledge ourselves for the solution of the riddle.” This challenge has elicited but a single response, which is embraced in the following letter. The only quarrel we have with the epistle, is that its writer has declined giving us his name in full. We beg that he will take an early opportunity of doing this, and thus relieve us of the chance of that suspicion which was attached to the cryptography of the weekly journal above-mentioned—the suspicion of inditing ciphers to ourselves. The postmark of the letter is _Stonington, Conn._ S——, Ct., April 21, 1841. _To the Editor of Graham’s Magazine._