It is therefore not surprising that works of alchemy appeared in medieval Latin under Aristotle’s name. The names of Plato and Aristotle had headed the lists of alchemists in Greek manuscripts although no works ascribed to Aristotle have been preserved in the same.[772] Berthelot, however, speaks of a pseudo-Aristotle in Arabic,[773] and in an Oxford manuscript of the thirteenth century under the name of Aristotle appears a treatise _On the twelve waters of the secret river_ said to be “translated from Arabic into Latin.”[774] In the preface the author promises that whoever becomes skilled, adept, and expert in these twelve waters will never lose hope nor be depressed by want. He regards this treatise as the chief among his works, since he has learned these waters by experiment. They are all chemical rather than medical; a brief “chapter” or paragraph is devoted to each. In another manuscript at the Bodleian two brief tracts are ascribed to Aristotle; one describes the seven metals, the other deals with transmutation.[775] In a single manuscript at Munich both a theoretical treatise in medicine and alchemy and a _Practica_ are attributed to Aristotle, and in two other manuscripts he is credited with the _Book of Seventy Precepts_ which sometimes is ascribed to Geber.[776] Thomas of Cantimpré cites Aristotle in the _Lumen luminum_ as saying that the best gold is made from yellow copper ore and the urine of a boy, but Thomas hastens to add that such gold is best in color rather than in substance.[777] The translation of the _Lumen luminum_ is ascribed both to Michael Scot and brother Elias.[778] Aristotle is quoted several times in _De alchimia_, ascribed to Albertus Magnus, but only in the later “Additions” to it, where Roger Bacon also is cited, is the specific title _Liber de perfecto magisterio_ given as Aristotle’s.[779] Sometimes works of alchemy were very carelessly ascribed to Aristotle, when it is perfectly evident from the works themselves that they could not have been written by him.[780] [Sidenote: Aristotle and Alexander as alchemists.]