VENTURA, Lorenzo.

A very good, tall copy of the first edition of this thorough alchemical manual on the preparation of the Philosopher’s Stone – a probable source for Ben Jonson’s play ‘The Alchemist’ and consulted by Isaac Newton. Little is known about Lorenzo Ventura, whom the title describes as a doctor of arts and medicine from the Veneto. In the dedication of this work, addressed to Otto Heinrich, Count Palatine, he states that, during four years of travels in France and Italy, he gathered 200 printed books and 50 mss on alchemy, which he offered to the Palatine library. Based on medieval theories, ‘De ratione’ focuses on the making of the alchemical ‘elixir’, a substance capable of turning base metals into gold. Part I – Ventura’s work proper – begins with a definition of ‘the art of alchemy’ and its principles, a critique of detractors, the nature of the elixir called Philosopher’s Stone, and why ancient philosophers kept its preparation secret by writing about it ‘sub figura’ (i.e., allegorically, obscurely). The Stone, produced out of one element only, includes nevertheless multiple substances. Important is the chapter on potential starting points for its production – silver, gold, sulphur or quicksilver – what works and what doesn’t. Ventura also explains how to fit the substance correctly into a container, what furnace to use (the ‘Athanor’), how much heat, and the various chemical stages (putrefactio, dealbatio, sublimatio, etc.). It concludes with alchemical verse in Italian and Latin, and a short text called ‘Alchemy talking about itself’, beginning ‘Ego sum angelicae sapientiae fulgor’. Parts II and III include sundry medieval works on the Philosopher’s Stone. The first is ‘Compendium alchimiae’ by the pseudo-John of Garland, but written by Martin Ortolan (fl. C14), similarly concerned with the preparation of the ‘elixir’, as well as with the Tabula Smaragdina, a short Hermetic text highly influential for Arabic and European alchemy. This is followed by Arnaldus de Villanova’s short commentary to ‘Compendium’, and John of Garland’s ‘De preparatione elixir’, with various methods of preparation and dozens of sections each devoted to specific minerals. The last is ‘De alchimia et rebus metallicis’, a section of Vincent of Beauvais’s ‘Speculum’, devoted to the properties of metals, the elixir and chemical processes, based on Avicenna, Rhazes, Dioscorides, etc. All are accompanied by copious indexes. An important early alchemical collection.