The Chemistry of Alchemy Read online

  To collect saltpeter, Sendivogius probably warmed niter with acid to remove the sal ammoniac and fixed salt and then re-crystallized the saltpeter to purify it. To generate the component of saltpeter that would support combustion (which we now know is oxygen), he could heat the saltpeter, which would release oxygen—and it was the identification of oxygen that would release the modern age of chemistry.

  Eventually. But not by Sendivogius. Oxygen would be rediscovered by Antoine Lavoisier in the last quarter of the eighteenth century. But if Sendivogius and others knew about oxygen, why doesn't the credit rest with them? Because, since the Islamic authors brought Zosimos to western Europe, Sendivogius and the others labored under the belief that if something, such as oxygen, were an element, then it had to be found in some proportion in all materials. Lavoisier said oxygen was a pure element. All on its own. Standalone.

  That was the gestalt.

  Furthermore, though alchemists often used balances to track the mass of their ingredients and products, oxygen is a gas, and that notion was not yet fully in place. What is the mass of a gas? Lavoisier would know, but Sendivogius did not.

  Good news, though. Gases would soon be better understood and the person responsible for the understanding would be an alchemist, too. In fact, we meet that person next.

  But first, to the barnyard! To extract the water that does not wet hands.

  DEMONSTRATION 14. THE POO PLAN

  We started this demonstration with great expectations, but we were soon mired down. After reading our account, we doubt that anyone will want to follow in our footsteps, but we feel compelled to share.

  THE POO PLAN

  When Sendivogius euphemistically said to start with “barnyard soil,” he meant manure. Luckily we have connections, so we were able to procure some manure.10 In fact, our friend's exact words were “take as much as you want!” The manure, however, had to be in a certain state of decomposition; specifically, it had to have a yellow-white crust of niter salts formed from bacterial decomposition of urine in the manure. Because the stables we used for our source of manure are kept scrupulously clean, finding manure was no problem, but finding old manure was a problem.

  Artificially aging our manure in the lab didn't seem to do the trick and invoked the ire (and disgust) of lab mates, so we tried a dark, damp shed, but we succeeded only in raising the interest of neighborhood canines. Luckily, one day our benefactor (see previous endnote) was out jogging and spotted a beautifully crusted pile in her path. She took a picture with her cell phone (jogging in place—at a distance) and we were able to make the harvest!

  That's when our problems began.

  We brought the specimen back to the lab (through the backdoor) and began the extraction and analysis.

  To confirm Sendivogius's findings, we needed to test for potassium nitrate, ammonium chloride, and potassium carbonate—that is, saltpeter, sal ammoniac, and fixed salt. The test kits we purchased were swimming-pool and aquarium tests for nitrates, ammonia, and chlorides, but we did not bother to list these in “Stores and Ores” as we assume you, as a reasonable person, will not want to try this at home.

  The tests, however, presented a problem. While the tests were accurate, they are based on color changes, and, well, poo is brown. All of our extractions resulted in lovely brown liquid (leachate) that rendered any subtle color changes undetectable.

  Quick list: we tried aquarium-clarifying solutions, activated charcoal, filtration, settling, and carefully scraping off just the crust (an operation that required a particle mask, gloves, goggles, and a good gag reflex), so that's where we stopped. (We later learned we might have been able to bubble the exhaust from decomposing urine through salt water to make sal ammoniac, but we didn't know in time to try it. Oh, darn.)

  Luckily, ammonium chloride, or sal ammoniac, is naturally volatile, that is, on gentle heating in a flask it will decompose into the vapor phase and reform on the sides of the flask. Strictly speaking, sal ammoniac does not sublime like our sulfur did in demonstration 2 because sal ammoniac dissociates into ammonia and hydrogen chloride and reforms ammonium chloride, sal ammoniac, when it deposits. But sal ammoniac volatizes nicely in its own way and, in fact, volatilization is a method for purifying raw sal ammoniac.

  Another fact, sal ammoniac was originally harvested from the chimneys of camel-dung-burning furnaces, and, for completeness, we would like to report we tried this, too. We built a brick, manure-burning furnace with a nested-flowerpots chimney and burned horse manure, having no camels at the ready. Nevertheless, after quite a bit of manure burning and long-winded explanations to neighbors and friends, we did not find any evidence of a deposit in our chimney. We decided it might have worked for the ancients, but it also might have required decades of seasoning and dung burning, which was not in our schedule.

  However, based on sal ammoniac's property of volatility, we put some poo leachate into a glass beaker and pushed it into a well-ventilated corner to see if it would deposit on the glass sides. We walked away.

  The walking away was a good idea; the returning in a few days—not so much.

  We did find a white crust had formed on the sides of the beaker (yay!), so we carefully scraped off as much as we could and tested it for ammonia. Positive. So far, so good. We tested it for chloride, and the test was negative. Not so good.

  Looking carefully at our chlorine test kit, we realized it was designed for detecting very high chlorine levels that would be undesirable in a swimming pool. We did not have very high chlorine levels. We were scraping material off the side of the beaker one crystal at a time, so our choices were to process more poo and gather a larger amount of crystals or concentrate the material we had. We opted to concentrate.

  Concentrating presented its own problem because one of the ways to get rid of chlorine in water is to boil it. We had already shown ourselves that ammonium chloride will leave solution on standing, so we neutralized our solution with a small amount of baking soda (using a base to suppress the formation of volatile hydrogen chloride, an acid) and warmed the solution gently. Testing our concentrated solution, we successfully registered chloride on the chloride test but admit our procedure would not pass any inspection in an analytical lab. But we put a big checkmark in the notebook: ammonium, check; chloride, check; ammonium chloride, check; sal ammoniac, check.

  Moving on.

  Testing for the fixed salt, a mixture of potassium carbonate and sodium carbonate, was not difficult. The fixed salt is a base very much like baking soda. Being aware, as most folks are, that mixed vinegar and baking soda effervesce, which is to say, they fizz, we evaporated some leachate to dryness, dropped on a little vinegar, and it fizzed.

  Fixed salt, check.

  Moving on.

  The test for nitrates also went well. Nitrates are formed in barnyard soil by bacterial action on amino acids and hippuric acid, a component of herbivore urine, which horses have in abundance. Interestingly, one procedure we found for generating nitrates from manure advised to check with local regulations before proceeding because some municipalities have laws regarding the manufacture of nitrates. Their concern is legitimate. One of the more nefarious uses of nitrates is to make gunpowder and other explosives. So if you decide to do the poo plan, check, but don't worry. The amount of nitrate generated wouldn't blow the nose off a gnat.

  We placed a checkmark next to saltpeter in the notebook.

  So, in retrospect, perhaps the adventure was not so bad. But we still do not recommend it.

  DISPOSAL

  All of the waste produced in the next demonstration can be disposed of down the sink. The saltpeter solutions are safe to flush to the sewer if followed by water because, according to Sendivogius, saltpeter is part of “the pure salt of the Earth.”11

  THE WATER OF OUR DEW

  After our last narrative, the title of this demonstration may engender suspicion, but be assured, no excrement is involved.

  Directly.

  But indirectly, yes. Nitrogen i
s essential to plant and animal life as we now understand it, and nitrates are used very efficiently by plants as a source of nitrogen. In fact, some plants, principally legumes, contain nodules on their roots to symbiotically house nitrate-forming bacteria. The nitrates formed in manure are why manure is an excellent fertilizer.

  Furthermore, Sendivogius observed,12

  the water of our dew, from which is extracted the saltpetre of the philosophers’, [is formed]…when it rains…the rain takes from the air a certain vital force and joins it to the nitrous salt…of the earth…and in consequence a great abundance of corn grows on the earth, as daily experience teaches.

  Impressively, he was right. Rainwater does sometimes contain nitrates formed from the nitrogen-oxygen compounds created in lightning strikes through our nitrogen-oxygen atmosphere, which brings nitrogen to earth in the water of our dew.

  There are those, however, who prefer not to collect rainwater or spread manure on their houseplants, so for these purposes, artificial manures have been developed in the form of commercial plant food.

  Examination of the contents on a package of commercial plant food reveals that it contains phosphorus, nitrogen, and potassium, which are essential plant nutrients. Saltpeter, a mixture of sodium and potassium nitrates, will contain two of these nutrients.

  So Sendivogius was right as rain.

  A nutrient as necessary as water for plants—but water which does not wet hands.

  SPIRIT OF THE EARTH

  Sendivogius also said saltpeter had a component in it that would support combustion. Let's test it.

  Please put on your safety glasses. Give us credit; we required only reading glasses for the poo plan and examination of the plant food, so we are reasonable, but you need safety glasses for this next demonstration. Also check on the location of your fire extinguisher. We'll be lighting candles and such.

  Find one of the wooden tapers we suggested for purchase in “Stores and Ores” and have it out and ready to light. Set up a candle and light it.

  Take about a teaspoon (5 milliliters) of saltpeter (sodium or potassium nitrate) and put it into a 250-milliliter Erlenmeyer flask. Do not use more than a teaspoon. Put on garden gloves to hold the flask because the flask is going to get warm.

  Shake the crystals down into the bottom of the flask and then warm the flask in the cast-iron skillet at about 50 percent power for about three minutes with your ventilation on full power. When the saltpeter has melted, turn off the burner, light your taper in the candle, pull it out of the flame, blow it out, and while it is still glowing, stick the smoldering end into the Erlenmeyer flask and into the melted saltpeter. The taper should flare up again and sputter for a good while because the heated nitrate has decomposed to provide an oxygen-rich atmosphere, and the oxygen feeds the flame.

  Score one more for Sendivogius.

  FIRE AND SALT

  As we said in the preceding chapter, Sendivogius wasn't the only alchemist fascinated by saltpeter. Blaise de Vigenère noted in particular that, even though saltpeter can promote fire, when placed in water, it draws in heat, cooling the environment considerably.

  Put on your safety glasses and place about a half cup (125 milliliters) of room-temperature distilled water in a clean Erlenmeyer flask. Add about a teaspoon (5 milliliters) of saltpeter and swirl. Place the bottom of the flask on the back of your hand or inner forearm and feel how cool it becomes. To the alchemists, this must have seemed like saltpeter acted contrary to itself!

  Yet despite their accurate observations, the alchemists kept missing the mark. It would take nearly a hundred fifty years to find a way through the fog, but in the next chapter we meet an alchemist who lights the way.

  God has given me a pious and noble wife; I retired with her to Vilvorde and there for seven years I dedicated myself to pyrotechny.

  Johannes Baptista van Helmont, alchemist, ca. 1600*

  For all the texture in our tale so far, there remains one truth: laborers or scholars, charlatans or lords, the alchemists longed to understand nature. The Belgian Johannes van Helmont was one such alchemist and, through his efforts, the marker moved forward. Belligerent and arrogant, mystic and philosopher; before Van Helmont, there were Paracelsians; after Van Helmont, there were Helmontians.

  JOHANNES VAN HELMONT

  Despite the pastoral picture painted by our opening quote, Johannes van Helmont (1579–1644)1 was a quarrelsome man; then again, he lived in quarrelsome times. Born in Brussels under Spanish rule, Van Helmont knew little peace. The Dutch War of Independence (1568–1648) began before his birth and ended after he died.

  Though most Dutch, including Van Helmont, remained devout Catholics, the strict Catholicism brought by the Spanish rulers included the Jesuit presence of the Catholic Counter-Reformation and demanded rigorous uniformity. Summarized by Saint Ignatius of Loyola, founder of the Jesuits, the Society of Jesus, “What I see as white, I will believe to be black if the hierarchical Church thus determines it.”2

  And to assist in everyone's eyesight, there was the Spanish Inquisition.

  Unique among the policing arms of the Catholic Church, the Spanish Inquisition was controlled completely by the Spanish monarchy with no appeal to the pope. The operations were essentially the same—thousands of savage executions; long-term arrest, torture, and imprisonment; fines; and property confiscation—but the political mote in the eye of the inquisitor was perhaps a bit more pronounced. The influence of this presence on the seventeenth-century Dutch mentality was significant; yet initially, at least, Van Helmont's life went untouched.

  The youngest of five children in a family of landowners, Van Helmont had access to advanced education, which he pursued but at first took no degree. With the independence allotted the son of a comfortable family, he sampled the offerings of other schools of thought, including mystics and opponents of natural magic, but he found this approach unsatisfying as well. He considered the study of law and geography, with the nearness of Portugal and the opening up of the New World, but it would be the Old World that would keep him where he was. Disappointed with his years in study, he gave away his books but said it would have been better to burn them. Eventually he was drawn to medicine, though, as before, he found much in need of criticism, including the Galenic approach of the times.

  Van Helmont also saw Aristotle as outmoded and said instead of ancient Greeks, students needed mathematics, geography, political economy, natural history, and mineralogy, and

  to know…the first principles of bodies…their…volatility, separation,…transformations,…corruption,…solution, coagulation…not by naked discourse but by handicraft demonstration of the fire…by distilling, moistening, drying, calcining, resolving, as Nature works.3

  He found more to like in the Paracelsian approach, but not uncritically and not always respectfully. Accepting the bogus history of Basil Valentine as valid, he asserted Valentine had predated Paracelsus; therefore, Paracelsus had stolen ideas from Valentine without credit. Nonetheless, in common with Paracelsus, he thought alchemy found its noblest employment in the purification of medicines. Like Paracelsus, he sought to identify classes of disease, such as occupational diseases, and he categorized disease by cause: poison, sin, and results of wounds.

  However, whereas Paracelsus recommended potable (drinkable) gold and silver as well as pearls as medicines, Van Helmont observed they passed through the body undigested and were, therefore, useless. He recommended against taking arsenic in any form (which we agree with), regardless of the advice of Paracelsus, but then he used iodine-laden seaweed to treat iodine-deficiency goiter as Paracelsus did.

  He prescribed powdered shells (calcium carbonate) for stomach acid, a remedy still used today in antacids. Yet he tried worms found in the eyes of toads or oil in which an Irishman had placed a stone as a remedy for the plague. But one can only imagine the desperation doctors must have felt in the face of the plague. At least Van Helmont was willing to treat patients when the plague hit. He also had the courage to
reject the use of bleeding and strong laxatives or emetics, which was certainly flying in the face of convention.

  He had some success as a doctor and was invited to the court of Rudolf II but turned it down, saying he wanted to devote himself to finding a better understanding of nature rather than “live on the misery of my fellow men.”4 Then, around the age of thirty, he married Margaret van Ranst, heir to four productive estates. He retired with his wife to her estates and built an alchemical workroom to continue his alchemical research.

  We feel quite comfortable naming his efforts “research” because of the critical way his alchemy advanced. He worked from a solid, conceptual basis. He said the four-element description—fire, water, air, and earth—was wrong. Fire was not material because it could pass through glass. Witnessing what we would call water spots—the residue left behind when impure water evaporates—he said water leaves an earthy residue; therefore, earth could be made from water and earth was not a primary material. Compressed air didn't turn into water, even in an air gun able to put a projectile through a board, so only air and water were the primary materials. Moreover, Van Helmont used precise measurement to support his conclusions.

  Precise, quantitative measurement was not foreign to the artisan; indeed, it was essential to the metallurgist and miner. Without precise measurement, there could be no assay. Measurement was not avoided by alchemists, either. The weight of a yield could be used to guide their trials. Van Helmont, however, recognized not only that yields were important but also that mass stayed the same over the course of many of his reactions, even when the ingredients going in looked entirely different from the product coming out. Not always an obvious concept.

  Figure 15.1. Johannes van Helmont (left) and son, Franciscus Mercurius. (Image courtesy of the California State University, Los Angeles, John F. Kennedy Memorial Library, Special Collections.)