Colors.
Experiments with colors are also of rather frequent occurrence in medieval manuscripts, and seem to a large extent to be anonymous. I have not sufficiently examined them to be able to say what additions may be made in the manuscripts of the thirteenth and fourteenth centuries to the recipes already given in the Compositiones ad tingenda, Mappe clavicula, and works of Heraclius and Theophilus of which we have already spoken. Like the Book of Twelve Waters, but not so widespread, is a treatise on twelve colors and their virtues,[2548] while a Virgilius appears again as the author of Pictorial Waters for Painting on Linen and Cloth.[2549] The works on colors of Peter of St. Audemar, of John Alcerius, and of John le Bègue have been printed by Mrs. Merrifield,[2550] but many brief anonymous collections of recipes concerning colors still remain in manuscript.[2551]
Necromantic experiments.
Other examples of necromantic experiments are found in the manuscripts than those of the Liber sacratus, Picatrix, and the Liber Vaccae, or those which are attributed to Michael Scot and Peter of Abano. An anonymous collection of “conjurations and invocations of spirits to discover thefts and other things of the sort” contains “among many other experiments” some concerning three angels in a crystal, a sibyl in a candle, four kings in a crystal, “a bearded old man,” and the ars episcopalis.[2552] A manuscript at Munich contains “A probable experiment to provoke spirits from all four quarters of the universe, whatever their condition, order, and station, by means of the mass.” “A good experiment in astrology of Master John of Belton” turns out to be necromantic, consisting largely in writing and repeating such words as the Tetragrammaton.[2553]
Experimentum in dubiis.
An “Experiment in cases of doubt” from an early thirteenth century manuscript at Erfurt[2554] may perhaps be described more fully. It should be begun during the March equinox early in the night with psalms and prayers. Starting forth to a spot where potter’s clay may be found, one repeats the Paternoster and Credo as one leaves his house or church. On the road he repeats seven psalms, and if he meets any passers-by, returns no answer to them. Having reached the potter’s earth, he plants his heel upon it and turning successively to the East, South, and North, repeats the magic word “Syos” to each of those cardinal points. Turning to the East again, he utters a short prayer beginning, “Force eternal, innumerable power, true presence of things, I suppliantly beg your clemency.” Then with a trowel with a white handle he cuts the earth about his heel, and digs up enough of it for his purpose, repeating the while a “Te Deum” and “Gloria in excelsis.” Having secured the clay by this ceremony, when he wishes to settle any doubtful question, he writes the words “Yes” and “No” on two bits of parchment, encloses these in pastilles of the clay, places a dish of holy water between the two pastilles, saying, “In the name of Father, Son, and Holy Ghost” and another pious phrase. Then he puts the pastilles in the water, adjuring them by the names of Elias and Moses to show him the truth of the matter in question, and opens for his answer the first pastille which floats towards him.
“A natural experiment.”
What we should regard as specimens of downright sorcery and magic are sometimes presented in the manuscripts not merely as “experiments,” but as instances of purely scientific procedure. Under the title, “A natural experiment,” which, however, is likewise called “ineffable,” a writer in a Paris manuscript[2555] describes three Practicae which may be used against enemies or serpents. Of these practical experiments the most interesting is the first, which the writer learned of when he was at Paris from Thomas de Pisan. This Thomas is also spoken of as of Bologna and as the physician of the French king. Evidently he is the father of the poetess, Christine de Pisan, Thomas of Bologna, who made astrological predictions and composed philters for the learned king, Charles V of France, and the duke of Burgundy, and who also wrote a letter on the philosopher’s stone.[2556] The object of Thomas’ “experiment” was the expulsion of the English companies of mercenaries from the French kingdom. He procured earth from the center and the four quarters of France and under a selected constellation made five images of lead or tin in the form of nude men. On the forehead of each he wrote the name of the king of England or one of the captains of the companies and on the jaw and breast astrological characters and names. These images were hollow and were filled with the aforesaid earth and at the proper astrological moment were buried in the five aforesaid regions with an incantation to the effect that this was the perpetual burial and total destruction and annihilation of the said captain and king, and the permanent expulsion of him and every official or adherent of his “so long as this work shall endure by God’s will, Amen.” The images were buried face down with their hands behind their backs, “and within a few months all the said companies had fled from the realm.” The writer states that all three of his Practicae are based on the first Practica of Thebit ben Corath, and notes that Albert the commentator has said in his Mirror[2557] that such images are purely natural like medical recipes.
Variety of experiments in medieval manuscripts.
It is hard to tell where to make an end of describing or even of merely illustrating the many collections and isolated examples of “experiments,” medical, chemical, culinary, artistic, magical, and necromantic, both of spurious and of anonymous authorship, to be found in medieval manuscripts. There are “experiments, good and best” which include such illusions as making a river appear to flow in a house;[2558] there are “some experiments in which occur many words written in a mystic form with vowels omitted”;[2559] there is an experiment to catch birds which begins by using the tongue of a dog;[2560] there are “Sounds of trumpets and other mathematical experiments,”[2561] and “A booklet of experiments for this and that,” which opens with instructions how to dissolve phlegmatic humors.[2562] In a single manuscript are “incantations and other experiments,” “Experiments of Alexander,” “experiments from Galen’s book of Dinamidia,” “general experiments,” “Experiments of Rusticus” who is perhaps Rusticus Elpidus, physician to Theodoric, king of the Ostrogoths, and “Experiments of Parisius, Abbot of St. Mark’s.”[2563] A certain group of experiments seems to be associated in some way with the emperor Frederick, presumably the Second.[2564] Another group of perhaps twenty-five experiments was collected at Paris about 1331 and “approved by divers doctors of the same dear university.”[2565] In an Escorial manuscript are experiments of a chancellor and cardinal.[2566]