The Chemistry of Alchemy Read online

  DISPOSAL

  The solutions from “Amethyst” and “Green Vitriol” need to be neutralized carefully with baking soda. You need to add the baking soda slowly and in a catch pan because the solution may bubble over and require containment.

  Once the solution is neutralized (no more fizzing), these can be disposed of down the drain as long as they are followed by a nice, long flush of cool water.

  AMETHYST

  Put about a half teaspoon (about 2 milliliters) of fine copper wire in an Erlenmeyer flask. Add about a quarter cup (60 milliliters) pH-lowering solution and a quarter teaspoon (1 milliliter) table salt (sodium chloride). Warm the solution at about 40 percent power until you get a pretty amethyst solution. Remove it from the heat and let it cool with swirling. The solution should slowly (within a week) turn green upon exposure to air.

  GREEN VITRIOL

  Add a pinch of steel wool to an Erlenmeyer flask and cover with water. Then add about a half teaspoon (2 milliliters) pH-lowering solution (Add Acid!). Warm this solution at about 40 percent power until the steel wool has dissolved. Remove from the heat and allow the solution to cool to room temperature. When it has cooled, cover it very loosely with plastic wrap or a sandwich bag and secure the wrap with the rubber band around the neck of the Erlenmeyer flask. Set it someplace where it will be safe from molestation. In time, crystals of green vitriol will settle on the bottom of the flask.

  The above demonstrations are just a few gleaned from Boyle's work, chosen because they are colorful and relatively safe, but Boyle's fascination with all things alchemical made him a hugely prolific and productive worker and writer. In the next chapter we will walk again with the Honorable Robert Boyle and learn more of the works and writings of our more-than-one-chapter friend.

  I shall not successfully, and must confesse that I canot very cheerfully, obey you.

  Robert Boyle to John Endicott,

  Governor of Massachusetts, ca. 1650*

  As seen from the above quote, Robert Boyle (1627–1691) was independent.1 In this response to Governor Endicott's request for intervention in a political situation, Boyle replied firmly, and a little impolitely, that he would not. This same certitude would secure Boyle a pedestal in the halls of science—but also cause his missed opportunity—and yet, in the balance, confirm him as a most worthy hero.

  There were reasons for Boyle's assertiveness. He was born to an affluent English family, and while his mother died when he was three, he had thirteen older siblings to dote on their youngest brother, and they did. One brother took the twelve-year-old Boyle on a continental tour, and on this tour he read Galileo's newly published Dialogue on the Two Chief World Systems. When he returned at seventeen, England was in the midst of a Civil War, his father was dead, and much of his family fortune was lost, but he inherited property on which he could live, though not sumptuously. Through his sister Lady Ranelagh, Boyle met Samuel Hartlib, of the Hartlib circle, and Hartlib fired Boyle's interest in medicine, and, as a consequence, alchemy. Boyle set aside an area for experiments in his manor and began his lifelong love.

  While never robust, Boyle was a bit of a hypochondriac,2 and he made medicines for himself and anyone else who would take them. As these medicines sometimes contained mercury compounds, animal parts, and even “perpetual pills” of antimony that could be recovered and used again (size not specified), volunteers may have been sparse. A highly spiritual person, Boyle wrote religious tracts, which he also presented to his friends. While these often contained pithy gems, they were otherwise diffuse, wordy, and meandering, perhaps due to Boyle's weak eyesight, which may have necessitated dictation rather than writing by hand. The same style extended to his writings on experimental investigations, including his work with his air pump, newly invented by Otto von Guericke.

  Figure 20.1. Robert Boyle. (Image courtesy of the California State University, Los Angeles, John F. Kennedy Memorial Library, Special Collections.)

  Boyle began his investigations with his air pump in Oxford, where he took rooms near University College in 1654, perhaps to be closer to the intellectual milieu. With this pump and with delicate and ingenious barometer-like instruments, he measured the pressure of trapped gases while recording their volume and found that the volume and pressure were mathematically related: as the pressure increased, the gas volume decreased in a consistent proportion. That is, when you squeeze on a balloon, it gets smaller, and to reduce the size farther, you have to squeeze harder—in a proportion predicted by Boyle's law, as the relationship is called in his honor.

  The importance of Boyle's discovery may be appreciated by contrasting it with the conjecture the experiment was meant to disprove. Franciscus Linus, a Jesuit, asserted that mercury in a barometer tube was held up by an invisible thread.3 Compared to the invisible-thread explanation, the inverse proportionality between pressure and volume was a quantum leap. Yet for all Boyle's fascination with his air pump, an assistant was still able to remark, “His greatest delight is chymistrey.”4

  In advance of his move to Oxford, his sister Lady Ranelagh, once again had paved the way. She located an apothecary who allowed Boyle use of his equipment for alchemy and found space in which he could work. At the time, there were no chemistry laboratories, per se, so persons of an alchemical bent worked in their homes or gardens, and at times in coffeehouses and kitchens. At best, if they were very wealthy, like the English king Charles II, they had a well-equipped private workroom called an elaboratory. When Boyle met George Starkey, Starkey was working out of his rooms.

  GEORGE STARKEY IN ENGLAND

  Starkey was probably introduced to Boyle by Hartlib as a physician. One year apart in age and in their twenties, the two young men soon found their mutual interest and plunged enthusiastically into alchemy. Boyle had read about transmutation and the philosophers’ stone but had become frustrated in his attempts at reproducing results. Later he would complain, “These writers, after they have frequently called their reader their son and made solemn professions…that they will disclose to him their secrets…put him off with riddles instead of instructions.”5 Starkey, more experienced, told Boyle about the work of Van Helmont, which was more clearly written and emphasized measurement and analysis in alchemical research. And Starkey showed Boyle a few things, such as how to make philosophical mercury, the true path, Starkey said, to the philosophers’ stone.

  The philosophical mercury, as Starkey relayed to Boyle, was mercury ultra-purified with antimony. A fascinating exploration of this process and other alchemy of Starkey is grandly elaborated in Alchemy Tried in the Fire, by historians William Newman and Lawrence Principe, which we won't attempt to rival. Here it must suffice to say that the instructions Starkey conveyed to Boyle were a logical, stepwise procedure that Boyle must have loved. Boyle was already hooked. Now, with Starkey's help, he was empowered.

  In the introduction to part 4, we said we detected a subtle shift in the way alchemists referred to themselves during the seventeenth century, being more likely to say “chymia” or some variation rather than alchemy. We noted this was not particularly new, the words had been used interchangeably for some time and there was no convention of alchemists to decide the preferred handle. But in Boyle's case, the choice was not so subliminal. He did not want to be identified with the vulgar alchemist. He was Robert Boyle, son of the Earl of Cork, heir to Stalbridge. He was a chymist, not an alchemist.

  We presented what is perhaps evidence of Boyle's desire to be distanced from those identified as alchemists when we noted, in the demonstration of last chapter, Boyle's omission of acknowledgement of the work of Sennert and Starkey. As the fourteenth child of the Earl of Cork and a member of a distinguished brood, Boyle may have felt the pressure to make a name for himself, which did not include Starkey as coauthor. And surely Starkey must have known this was a possible outcome of his collaboration with Boyle. But perhaps caught up in the camaraderie and impressed by the wealth and advantage of Boyle, Starkey saw himself likewise becoming a respected c
hymist in the Hartlib circle. However Starkey was an outlander and a bit of a huckster, as we noted last chapter, so his ambitions were not realized. Boyle appropriated Starkey's work, Starkey became belligerent, he was dropped from the Hartlib circle, and he died in the plague.

  Boyle, however, was off and running. Liberated by Van Helmont's outspoken advocacy of alchemy for alchemy's sake, not solely in the search of the philosophers’ stone, Boyle produced result after result, only a few of which can be expanded here.

  BOYLE AS CHYMIST

  Take, for instance, his work with acids and bases.

  The concept of acid and base is fundamental to modern chemistry. By the most inclusive definition, nearly all solution chemistry can be described by an acid/base model. Because solution chemistry is the chemistry of oceans, cells, petroleum, and perhaps Mars, Boyle's contribution to the understanding of acids and bases is important. As is shown in the demonstration that accompanies this chapter, acids and bases react with the color-producing chemicals in many strongly colored natural materials such as violets, blackberries, plums, and our favorite: purple cabbage.

  Boyle would become famous not just for the lovely colors produced (though they are lovely) but also for developing the color changes as an analytical tool. With this tool, he showed all plant-ash alkali salts contain the same base, contrary to popular belief, and not all salts are acids or bases, again not as expected.

  Boyle experimented with Van Helmont's gases, even discovering some of his own. He found dilute nitric acid acting on iron would generate an explosive gas, hydrogen. He proved to his satisfaction all animals required air to live by depriving them of it in a bell jar evacuated by his air pump. Though this same result could have been arrived at by common experience or slightly less brutally by smothering, sensitivity was not a requisite of Boyle's experimental design. In other areas of investigation, such as dissection, live animals and even indigents were employed.

  He also set his bell jar on water and found the water produced bubbles when he applied vacuum. At this observation, he commented, “in common water there [may be] concealed air enough [for] fishes; and…may be separable from the water that strains through their gills.”6 This may have been one of the first times he missed identifying oxygen. There would be others.

  Later, Boyle noticed that a flame could not exist without air but gunpowder in a vacuum could be burned by light focused through a magnifying glass. He proposed “a fifth part of air in gunpowder,”7 and thought air might be trapped in the saltpeter of gunpowder when it crystallized, but he found the same result when he isolated saltpeter under a vacuum. He concluded there was a “volatile niter abounding in the air,”8 and there, for some reason, rather than putting it together that the saltpeter contained a new gas, his ruminations stopped.

  Franciscus Mercurius van Helmont demonstrated that tin gains mass when heated. Boyle had the idea of demonstrating that it was a component of air that added to the tin by heating a sealed container of tin. The first time he tried, he kept too much air in the container, so the container burst when heated. The second time, Boyle opened the container and let in air before he reweighed it, nullifying the experiment. Boyle noted this—but assigned the added weight to the action of fire. Oxygen missed again.

  Some one hundred years later, Lavoisier would demonstrate the role of a new element, oxygen, in combustion by burning a diamond in a sealed container and weighing before and after. With this evidence, he broke free from the definition of an element as a material that was present in all things to the concept of the standalone element—the foundation of modern chemistry. Why was Boyle not able to do this?

  Was it equipment? Boyle had the finest instrument makers in London at his command. He used a precision barometer in his work that resulted in Boyle's law. He built an air pump. He built a reliable thermometer. He could have built a precision balance. Then was he out of ideas?

  If he was, he wasn't the only one.

  ISAAC NEWTON

  Boyle's acquaintance, Isaac Newton (1642–1727), was fifteen years Boyle's junior and several rungs lower on the social ladder—to begin with. He caught up. By his midforties he had published his laws of motion and universal gravitation and perhaps looked at alchemy as unplowed ground. He did experiments in his garden behind his rooms and, like others, became a bit obsessed. His assistant said, “He very rarely went to bed before two or three of the clock, the fire scarcely going out either night or day, till he had finished his chemical experiments…he would sometimes…look into an old mouldy book.”9

  Newton, too, believed in metallic transmutation and the philosophers’ stone as the route to gain it. And Newton, too, breathed oxygen but didn't see it.

  Newton explained gunpowder's power coming from gas, but he didn't attempt to isolate the gas or investigate its properties. He communicated with Boyle and they discussed much, but they did not collaborate on gases. What did they collaborate on? Recipes for the philosophers’ stone. Newton read Eirenaeus Philalethes but did not know he was Starkey; Boyle knew Starkey and did not know he was Eirenaeus Philalethes. The pseudonyms, riddles, veils of obscurity, blind alleys, Decknamen—perhaps they drove Newton to despair but inspired Boyle to write.

  BOYLE AS AUTHOR

  Boyle penned over forty books, many of them important classics that, like Boyle's law, significantly advanced the science. New Experiments and Observations Touching Cold (1665) explored thermal measurement and combinations of materials that changed temperature on mixing, sometimes dramatically, as we saw in the demonstration with last chapter. Experiments and Considerations Touching Colours (1664) investigated color changes and the basis for color, such as the indicators Boyle used for acids and bases. And, in 1661, there was The Sceptical Chymist, a proper tour de force.

  The Sceptical Chymist is truly well named. In it, Boyle attacked the obscurity of the alchemical writings, calling the vulgar alchemists apes and peacocks, whose “feathers make a great shew, but are neither solid nor useful.”10 He railed against the imprecision of alchemical principles. He rejected both the four elements of Aristotle and the three elements of Paracelsus—but contrary to custom, he did not make up a new set of elements to replace them. He said, essentially, the question was open.

  From the perspective of modern science, Boyle's position feels brilliant. To acknowledge the unknown, to question assumptions, to propose better investigations—this is the essence of enlightenment. So how was it that such a mind, with ample experimental and philosophical hints, still could not make the final step that would lead to the conclusion that vital air, oxygen, was an element, independent and individual?

  Was it really bad luck?

  Or did he have a blind spot?

  To make Lavoisier's leap to free elements would have meant letting go of transmutation. If substances couldn't be resolved into sulfur, mercury, and salt—or fire, earth, air, and water—or whatever prima materia one should choose, then these couldn't be arranged into the product desired. For Boyle to admit that transmutation was an impossibility would be to deny beliefs held for centuries—and the evidence of his own eyes.

  For Robert Boyle had seen transmutation, and he believed.

  A traveler had shown him the operation. Boyle relayed the story:

  [Upon] Lead being strongly melted, the Traveller opened a small piece of folded paper wherein there appear'd to be some grains, but not very many, of a powder that seemed somewhat transparent almost like exceeding small Rubies, and was of a very fine and beautifull red. Of this he tooke carelessly enough, and without weighing it, upon the point of a knife as much as I guessed to be about a grain…. I desired him to cast in the powder himselfe which he did whilst I stood by and looked on…. The Crucible having been kept till it was cool enough to be managed without doeing harme we remov'd it to the window where, instead of running Mercury, I was surprised to find a…Mass that…appear'd very yellow…. The Traveller…smiled.11

  The mass, said Boyle, tested to be pure gold.

  So how i
s it that we choose Boyle—a mimic, a cynic, a dupe of a charlatan—as our last hero? For this one reason: Boyle was willing to examine each idea, even a traveler's transmutation, and sift through it for truth. Accordingly, he tested palingenesis, the vegetable homunculus. He diligently burned cabbage to ash in his crucible, mixed the ash in water, and froze the mixture undisturbed.

  The result, he said, looked not at all like cabbage.12

  Therefore, for this one statement if no other, we will always laud the Honorable Robert Boyle. He was a skeptic, and he made skeptics of us all. We believe, had he lived long enough, he would have made the connection—but he did not.

  He eventually went to live with his sister Lady Ranelagh, and she continued to find room for his experiments and look to his needs. On December 23, 1691, his sister died.

  One week later, so did he.

  And so to the elaboratory of the Honorable Robert Boyle!

  DEMONSTRATION 20. THE COLOR OF ALCHEMY

  If you have not indulged in any of the demonstrations so far, please do this next demonstration. It doesn't require much—no specialty glassware or chemicals—and it is very satisfying. You probably already have everything you need at home and will need only to go the grocers for one item: cabbage. A purple cabbage to honor Boyle.

  If purple cabbage is in short supply, you can use a purple plum, dark-red apple skins, blackberries, or blueberries.

  DISPOSAL

  All of the leftovers can go in the trash or down the sink. However, when disposing of the liquids in the sink, do one at a time and do not start the next until the previous liquid has been flushed with a long rinse. Some of the materials could react with each other and create an unfortunate confusion in your pipes.

  PURPLE CABBAGE JUICE