De cometis

Master Petrus de Valesia, Physician of Zurich, cannot be its author, since he lived in the year of our Lord 1318. Bullinger also mentions him in his History of Zurich original: "de Rebus Tigurin", Book VI, chapter 6: "he also founded the altar of St. Mary Magdalene in Zurich at the Great Minster."

Nor can this book be assigned to Rodolphus Arzet, Physician of Zurich, as I have said, with due respect to the judgment of the renowned D. D. Hottinger, in his Library of Zurich, page 70. For no evidence exists that this Rodolphus Arzet is its author. The title of the book says: "Treatise by a Physician of Zurich," where the name "Physician" is used generally, for a medical doctor. Nowhere is a treatise by the physician Rodolphus Arzet cited, nor does it exist in Gesner, Simler, or Fries or anywhere else. Ludwig Lavater in his Catalogue of Comets, discussing the comet of the year 1472 at length, adds: "This comet is described by Eberhard Schleusinger, Physician of Zurich, in his little book on Comets, which has been printed." Lycosthenes also states in On Prodigies, page 489: "Eberhard Schleusinger, Physician of Zurich, in his little book on Comets, etc." Others also mention this treatise of Schleusinger, such as Gesner in his Bibliotheca. Fries, Bibliotheca, page 50b. Furthermore, this treatise was reprinted at Nuremberg in 1539 in quarto, and justly claimed for its author, Schleusinger.