The Chemistry of Alchemy Read online

  The Sun is its father, the moon its mother, the wind hath carried it in its belly, the earth is its nurse.

  The father of all perfection in the whole world is here.

  Its force or power is entire if it be converted into earth.

  Separate thou the earth from the fire, the subtle from the gross sweetly with great industry.

  It ascends from the earth to the heaven and again it descends to the earth and receives the force of things superior and inferior.

  By this means you shall have the glory of the whole world and thereby all obscurity shall fly from you.

  Its force is above all force. For it vanquishes every subtle thing and penetrates every solid thing.

  So was the world created.

  From this are and do come admirable adaptations whereof the means is here in this. Hence I am called Hermes Trismegist, having the three parts of the philosophy of the whole world.

  That which I have said of the operation of the Sun is accomplished and ended.5

  To the modern reader, these writings might seem like a literary Rorschach test—an inkblot out of which one could make what one wishes—but in the hands of the commentators, these words became the alchemists’ inspiration. What was the “operation of the Sun”? Why, making gold, of course. What was the “mediation”? The philosophers’ stone. How does one arrive at the philosophers’ stone? “Separate thou the earth from the fire, the subtle from the gross sweetly with great industry.” So they did.

  Alchemy became the Hermetic art, and air- and watertight vessels were called hermetically sealed. The part about the recipe for the elixir of life being found clutched in the hands of a dead man did not dissuade the alchemists. But little would. They had it on good authority—and besides, what if the legend were right?

  THE PHILOSOPHERS’ STONE

  Yet, as with most things, having the idea was one step; the execution, quite another. There were problems. Neither the emerald tablet nor any other authority said exactly how to make the philosophers’ stone. It was called the stone that is not a stone,6 and Roger Bacon interpreted stone to mean “cornerstone” or the beginning material7—which meant it could be anything. Was it animal, vegetable, or mineral? Yes. Was it solid, liquid, or gas? Yes.

  Alchemists, believing they had seen the philosophers’ stone, reported it, variously, to be saffron color…or the color of wild poppy…or perhaps red, white, black, yellow, blue, bluish-gray, or green…or sable with veins of silver. The stone was a glass-like powder, impalpable to the touch, solid and flexible, dry and yet unctuous, and spiritual and corporeal. It was sweet to the taste, fragrant, or smelled of heated sea salt, but the process of making it produced “poisonous fumes, for which eating bread, thickly spread with butter, would hardly be a safe and sufficient antidote,”8 so you were probably better off not smelling it at all. Witness poor Hermes in his grave with the tablet clenched in his hands. Given the disagreement about the appearance of the philosophers’ stone, disagreement on starting material or materials naturally followed.9

  STARTING MATERIALS

  There were some (relatively) odd proposals for starting materials. Roger Bacon thought it should be blood. Arnald of Brussels,10 a scribe who flourished in the early 1400s, before the general introduction of the printing press, kept a private collection of recipes he copied on commission, including examples for the philosophers’ stone. Some are quite creative and harder on toads than global warming. Others required common materials such as vinegar, sal ammoniac (ammonium chloride), sal alkali (baking soda), sal nitrum (sodium nitrate), and iron—while other ingredients were a little harder to come by, such as dragon's blood, which could be interpreted as the herb, the pigment, cinnabar (the red ore of mercury), or literally dragon's blood.

  After the circulation of Geber's Sum of Perfection (explored in chapter 3), most agreed the starting material should be mineral and the recipe should include mercury and sulfur. Steps in the process were seen as a marriage between the sulfur and the mercury, with sulfur as the male (dry) and mercury as the female (wet). The product of this marriage? The philosophers’ stone, the hermaphrodite.11

  Disagreement existed over whether one should start with mercury and sulfur or mercury alone (no imagery offered)—and there was one other small problem: by saying “mercury” they meant a substance that had the qualities of mercury, not necessarily quicksilver. Any molten metal might be a mercury. Likewise “sulfur” was something combustible and dry and not necessarily yellow or a powder.

  Furthermore, recipes of the day could call for “our vitriol, not that of the vulgar,” or “Pontick water,” which left much to the imagination. In his paper on “Chemical Translation,”12 by which he meant recasting alchemical recipes into modern chemical reactions, Lawrence Principe, chemist and noted historian of science, outlines more of these difficulties. An ingredient called “my vinegar” could mean vinegar with something added to have the properties needed—or another acid altogether. In addition, unbeknown to the alchemists, a starting material could have unidentified impurities, which would make it work well the first time but not so well the next. Modern chemists are well aware of these gremlins and know how to combat them, but the medieval alchemist was in the hands of chance.

  Another problem was lack of standard nomenclature (in fact, they didn't have the word nomenclature until the 1600s13). An ingredient name could mean one thing to one alchemist but a different thing to the next. Recipe books could contain copy errors, intentional deceptions, and alchemical imagination. Reference works could have been translated from Greek to Arabic to Latin to vernacular and maybe back to Greek. Many times books were written to attract the support of patrons, such as the works of Charnock, an Elizabethan seeker after the stone.14 When he wrote to Queen Elizabeth looking for support, he didn't have to worry too much about accuracy because he knew there was little chance she would roll up her voluminous sleeves and give it a try.

  THE PROCESS

  Interestingly, the description for the process of making the philosophers’ stone was fairly uniform, but then it was the alchemists’ standard fare: heat, purify, and heat again. Calcination, solution, digestion, distillation, sublimation. Knowing the chancy nature of their work, some alchemists added superfluous steps, such as distilling seventy times, knowing on one of those distillations the flask would break (or the alchemist trying to follow the directions would lose count), thus ensuring the fault was not in the recipe but in the cook. In fact, some recipes can be identified as Arabic in origin because of an Arabic “opt-out clause”: “a kind of phrase explicitly leaving the success of a procedure to God's discretion [such as]…by God's will…God willing.”15 If God was not willing, if the worker was unworthy, if the mercury was not pure enough, if you couldn't find a dragon to donate blood…

  Nonetheless, we did find one thing on which there was a surprising general agreement: the color changes.

  THE COLORS

  In the first stage, the material is black. Gradual heating turns the black to white. After that comes the show: the material assumes purple and green and then all the colors of the peacock's tail. Finally the stone (which is not a stone) gains the color of silver and then that of gold.16 As we will show in the demonstration that accompanies this chapter, the reaction described by these color changes is fully realizable with materials they had at hand, and if the alchemists were half as excited as we were the first time we saw it, they were pretty darn excited.

  But even when all went well and the glorious colors were achieved, the eureka to be heard ’round the world—a medicine to cure every metal and end every ill—never sounded.

  Why did the alchemists keep trying? For what was at stake, of course, but also for some we believe the love of the quest was as much as the lust for the goal. Chemistry is a contemplative art, and we suspect alchemy must have been the same. Charnock, on failing to gain support from Elizabeth I, retired with his daughter to a remote village where he made medicines and pigments and tended his fire. Watching
the colors, changes, and undulations is sometimes enough to be happy…

  Though for some, not as happy as others.

  BERNARD TRIVISAN

  When we last left Bernard Trivisan, he was the authority whom Thomas of Bologna sought to validate his potions as medicines, not poisons. At that time, Trivisan stood commanding and respected, but after that, in his account retold by the modern author Bernard Jaffe, things took a turn for the worse.

  Jaffe asserts that the search for the philosophers’ stone obsessed Trivisan. Trivisan knew metal came from the ground, so by analogy with plants, it must grow from a seed, and that was the seed he sought, his philosophers’ stone. He searched the writings of the ancient authorities and tried his hand at their methods. He decided other materials besides mercury and sulfur might make good candidates to start with—plants, rocks, body parts, excrement—and with each guess he repeated his calcinations…solutions…distillations…sublimations…

  Figure 6.1. The discovery of phosphorus while in search of the philosophers’ stone. (Gift of Fisher Scientific International. Image courtesy of the Chemical Heritage Foundation Collections.)

  He invested in the confidence ventures of glad-handers, and he allied with a friend, a Franciscan friar, and together they looked for answers. He labored for seventy years, lost his fortune, his friend the friar died, and still he failed, as he was destined. His last words, according to Jaffe, were, “To make gold, one must start with gold.”17

  But then Jaffe might have been able to end his tale better if Trivisan had not been so honest. In another autobiography by an alchemist, Denis Zachaire starts out on the same path as Trivisan, but instead of dying disillusioned and in poverty, he reports he actually, finally, after years of wandering, made gold on “Easter day of the year 1550 or thereabouts.” He then took his gold and his secret and retired with his wife to a remote region where he was able to live out his days in peace, assured that those who read his “little book” would not be able to seek him out. Something tells us he at least kept in contact with the bookseller to collect the profits of his little book.18

  Zachaire was not the only one to realize selling books was a more certain route to gold. Ben Jonson, playwright of the 1600s and author of this chapter's opening quote, has the butler tell Subtle, the alchemist, “A book, but barely reckoning thy impostures, Shall prove a true philosopher's stone to printers.”19

  But with all the legend, illusion, and chicanery, was there any saving grace in the search for the philosophers’ stone? Maybe one example will suffice: Hennig Brand was searching for the philosophers’ stone when he discovered phosphorus, the element that glows.

  HENNIG BRAND

  Hennig Brand (fl. 1670),20 an eccentric and die-hard dabbler in alchemy, still believed he could find the philosophers’ stone in the second half of the seventeenth century long after many others had folded up shop. Seeking a novel starting material, Brand collected a huge vat of urine, allowed it to rot until creatures grew in it, and then distilled it down repeatedly. At the end of his distillation he found a residue—that glowed under its own light. He had found the thirteenth element, phosphorus, but he must have believed he had found his stone.

  So this is our tale of the philosophers’ stone, peopled by romantics, eccentrics, dreamers, and bums. But not everyone who worked on the philosophers’ stone lived on the fringe. In fact, the heroes of our next chapter worked on the stone while in league with the artisans.

  But first, let's search for the philosophers’ stone!

  DEMONSTRATION 6. ERINA'S FABULOUS PHILOSOPHERS’ STONE

  Remember the color changes we said the alchemists saw while making the philosophers’ stone? In the first stage, the material is black. Gradual heating turns the black to white. Continued heating causes the evolution of yellow, purple, blue—all the colors of the peacock's tail. Finally the stone gains the color of silver and then that of gold. Now, however, we admit the situation is a bit more complicated. There were other color sequences reported, too, though the peacock's tail is the one mentioned most often, but perhaps more for romance than for actual frequency of observation.

  In 1963, in his paper on the possible chemical composition of the alchemists’ philosophers’ stone, chemist C. J. van Nieuwenburg reproduced another reported color sequence—black, white, yellow, and then red—a sequence he believes would have been observed in a “mercury only” approach to the philosophers’ stone.21 He began with a mixture of mercuric oxide (an oxygen salt of mercury) and mercury metal, which he said made a nearly black mixture. When he heated the mixture, it gradually went from black to white to yellow to red.

  In a second preparation, Nieuwenburg took a mixture of mercury, silver, and gold and dissolved it in aqua regia, a combination of nitric and hydrochloric acids (which we will discuss next demonstration). This mixture also went from black to white to yellow to red, but his final product was a silver-gold chloride salt that did not contain any mercury. The mercury, he decided, was a gratuitous ingredient, though it may have facilitated the breakup of the gold by amalgamation, and it provided the color change to white in the black-to-white step. In the final analysis, Nieuwenburg concluded he had made some interesting gold/silver alloys, but they would not cure a wart—let alone serve as a universal elixir—and were very lovely but would never be mistaken for gold.

  Likewise in our process, which is a mercury/sulfur approach, we will replicate our preferred color sequence, down to the peacock's tail, but our “mercury” will be molten pewter or tin, though the sulfur is real.

  DISPOSAL

  The used tin and/or pewter from this demonstration can go in the trash, but we keep ours in our alchemy collection on the mantel. We are not going to use sulfur water in any more demonstrations, so this, too, can be washed down the drain, but put it in slowly, bits at a time, and follow with lots of cool water (a two- to three-minute flush). Be careful to use a drain without a garbage disposal.

  PEACOCK'S TAIL

  Find your safety glasses, the pewter tokens we recommended for purchase in “Stores and Ores,” the cast-iron skillet, a 250-milliliter beaker or larger, tin shot, sal ammoniac (ammonium chloride), and your sulfur water from demonstration 4—though the sulfur water in this case is optional. It is not necessary to use sulfur to see the peacock's tail, but an alchemist would have approved. The alchemists always thought throwing in a little sulfur helped in a mercury/sulfur world.

  However, if you choose to include the sulfur-water step, you have to work outside with your hibachi. As before, if you have any suspicions about being allergic to sulfur, forego the sulfur part of the demonstration. If you don't know, assume you are and be careful. Work with a friend and, if you start to itch, get a headache, swell, or have trouble breathing, remove yourself from the area.

  If you want to skip the black and white stages of the color change and go to the peacock's tail, you don't have to use pewter or sulfur. Tin shot will work as well, and you can work on a stove with a good exhaust system.

  In any case, put on your safety glasses.

  GOING ALL THE WAY FROM BLACK TO GOLD WITH PEWTER? START HERE.

  Start the coals going in your hibachi, set the grill on the lowest setting, and retrieve the sulfur water you saved from demonstration 4. By now, the sulfur water has probably developed a vague, scrambled-egg odor, so depending on your feelings about scrambled eggs, this odor may be a factor in your decision to do the black-to-white step. If you decide to put on the whole show, put your sulfur water in your cast-iron skillet and set the skillet on the hibachi. Stir it gently while it is warming.

  Although you want the sulfur water to be as hot as possible without boiling, if it starts to boil, remove the skillet and use a tool to spread the coals out a bit.

  Once the sulfur water is warm and nicely mixed, put one of the pewter tokens in the sulfur water and leave it on for about two hours or as long as the coals hold out, stirring occasionally.

  As we mentioned before, alchemy is a contemplative occupatio
n. Like fishing. Or viewing a sunset. Or watching paint dry.

  Fish the pewter out every so often to see if it has darkened with a dull-gray coating. When it has darkened to your satisfaction, pull it out, rinse it off thoroughly, and dry it on paper towels.

  Voilà. First color: black.

  Bring your pewter and skillet back inside for the next steps.

  ONLY GOING FOR THE PEACOCK'S TAIL THEN GOLD? YOU CAN START HERE.

  For this phase of operations you can continue with the pewter from above or begin at this point with a teaspoon (5 milliliters) of tin shot.

  If you're using pewter, place the blackened pewter in a beaker and place the beaker in the middle of the skillet, set the burner to about 70 percent power, and wait. But this time only about one to two minutes.

  At first it will look like nothing is happening, but after two minutes or so, gently nudge the handle of the skillet. You should see the dark skin crack, revealing molten pewter underneath.

  If you are using tin, put the teaspoon of tin in a beaker in the middle of the skillet with the burner at about 75 percent power. After a few minutes the tin should start to darken and then develop a sheen on the surface as it approaches its melting point. Jiggle the pan gently from time to time, and when it hits the melting point, the tin will suddenly form a puddle.

  In the world of alchemy, “whitening” a metal meant to make it more like silver; therefore, when the silvery liquid metal breaks free from the black pewter or the darkened tin melts, we will call this whitening.

  Voilà; second color: white.

  Now for either the pewter or the tin, turn the burner up to about 80 percent power.

  Once again, wait.

  Gradually you will see the same brilliant, golden sheen come over the metal, pewter or tin, as we saw in demonstration 3, and it is still as impressive. This time, however, don't take it off the heat when the gold shows up. Instead, wait.

  Fairly soon you will see another oxide, this time a yellowish oxide, then a purple oxide, start to creep over the pewter/tin. Keep watching and eventually you will see an amazing sunset of purple, blue, and gold spread across the surface.