The Mutus Liber — “Mute Book” — is a work of few words. Most appear on its first plate, where we are told that the book’s author, “Altus”, has created “hieroglyphic figures” to illustrate the “hermetic philosophy”. They hover over a sleeping Jacob, dreaming of the angels on the ladder of heaven, one of whom is attempting to wake him with his trumpet. This is a biblical scene, but, for those in the know, it also provides keys to the secret of the Philosopher’s Stone, the mythical substance that could turn lead into gold. According to the modern alchemist Eugène Canseliet (1899–1982), since the trumpets are both igneous and vitreous, they represent saline, and the two angels are a metaphor for the “cohobation of the spirit on the material”. For full effect, he claims, you must read the enigmatic numbers and letters beneath the title backward.