edited by ROGER R. FESTA S c b l of Education, Box V-33 me University at Connecticut Storrs, CT 06268
Jean Rey: Unsung Prophet? Sidney Rosen 341 Astronomy Department University of illinois Urbana. iL 61801
In January 1775, Antoine Lavoisier sent to the Academie des Sciences in Paris his now-famous memoir on the calcination of metals that was to reduce the phlogiston theory to ashes in the history of science. Two months later, another chemist wrote a letter to the Academie, pointing out that Lavoisier's solution to the question of what happens when a heated metal becomes a calx had already been suggested some 145 years earlier ( I ). That second chemist was Pierre Bayen, Apothecary to the King's Army; the person to whom he referred was a 17thcentury French physician named Jean Rey. On the first of January 1630, a little book, privately printed, had appeared in the Bordeaux area of southwest France. The title was rather long: "Essays by Jean Rey, Doctor of Medicine, on the Search for the Cause of the Increase in Weight of Tin and Lead when they are Calcined." Within its 144 pages were 28 short essays. Not much is known about Jean Rey's life. He was horn about 1582in the little town of Le Bugue, the son of agreffier (one who collected taxes from lands put in his name and farmed). Jean's parents died when he was a boy, and he was raised by his elder brother. In 1609 he graduated from the University of Montpellier with an M.D. degree and set up a medical practice in his home town. Rey was, apparently, considered an excellent physician; there is a record of his having been requested to visit a noble patient at Toulouse, ahout a hundred miles away. I t is supposed that Rey died in 1645, but the year is not certain (I ). While there is little evidence that Rey was a practicing alchemist, he was most certainly acquainted with the language tributions of diStinguished chemists in the context of their lives. The column is designed far curriculum enrichment, allowing the secondary school teacher to enhance the vitality of chemistry with the sense of scholarshil) and adventure shared by chemists throughout history.
58
Journal of Chemical Education
and arcana of that profession. By 1600,alchemy in Europe was almost completely under the influence of the followers of Paraceisus. The abstract concepts of Salt, Sulfur, and Mercury had been added to the original Aristotelian elements: Earth, Water, Air, and Fire. Nowhere in his book does Rey admit to doing the actual experiments of calcining tin and lead and measuring changes in weight. The essays are introduced by a letter to Rey from Monsieur Brun, an apothecary from Bergerac, who had done the experiments and who essentially challenged Rey to provide an explanation of the results. Brun heated 2 lhs 6 oz of the purest English tin (from Cornwall) in an iron container for 6 hr; upon weighing the resulting white calx, he found 2 lbs 13 oz. Doing the same experiment with 6 lbs of lead, Brun found the calx diminished in weight. "I beg of you in all affection," Brun ends his letter, "to go to work on the cause of such a rare effect; and I will he wholly obligated if, by your means, this marvelous result is made clear to me" (1). The first 15 essays are devoted to proving that the element Air has weight. The basic argument used by Rey is that Air is composed of parts of different densities. Upon heating Air, the lighter densities are driven off, leaving the denser parts of the element around the metal which is being transformed into a calx by the same heat. Rey's arguments tell us that he was quite familiar with alchemical equipment, procedures, and language ( 2 ) . The point of this discussion becomes clear in Essay 16, where Rey points out that the reason the calx is heavier than the original tin metal is that during the heating process, the denser, and therefore heavier, air in the alchemical furnace adheres physically to the already formed calx. He uses the analogy of water making sand heavier by moistening and clinging to each grain (2).While Rey's explanation is made in physical terms, rather than chemical, it was close enough to the truth to interest a famous contemporary French intellectual, Father Marin Mersenne, and later to influence Lavoisier. In his first paper presented to the Academie, Lavoisier made no mention of Rey. However, after her husband's death, Mme. Lavoisier published a memoir in which Lavoisier writes that the discovery and reading of Jean Rey's sixteenth essay had some influence upon his thinking ( 1 ) . I t seems amazing that
Rey's hook should have been ignored for so many years; however, it was puhlished without the priuilege du roi and apparently in small quantity. Thus, even though Professor Spielman, a chemist a t the University of Strasbourg in 1770, recommended Rey's hook to his students, the chances are that they were unable to find a copy available ( I ) . Another reason for the eclipsing of Rey's work may have been the publication in 1673 of Sir Robert Boyle's "Essays of Effluvium." In this work. Bovle orooosed that the eain in weieht of a calx was caused by t i e absorption of 5orpuscles'bf fire" passing through the walls of the sealed container in which the caLv was formed. Boyle's explanation became widely accepted; undoubtedlv. the oooularitv of Isaac Newton's view of both light . and matter as %&pusc
