A treatise on the art of decyphering, and of writing in cypher. With an harmonic alphabet This book, "A treatise on the art of decyphering, and of writing in cypher.", by Philip Thicknesse, is a replication of a book originally published before 1772. It has been restored by human beings, page by page, so that you may enjoy it in a form as close to the original as possible. This book was created using print-on-demand technology. Thank you for supporting classic literature.