The Ten Most Beautiful Experiments
By George Johnson
|I will admit it: I skipped to the end. I did this before I even started reading. You see, I wanted to discover the wondrous conclusion promised by the book’s table of contents. Call it cheating – I like to think of it as reassurance. Who among you has not done the very same, for some thrill, for some revelation, for some security that all is indeed well that ends well? Who hasn’t let impatience breach the mighty walls of moral rectitude, suspense, chronology?
Yet so often the ending disappoints, and then the reading of the entire book becomes an exercise in just gritting your teeth and thinking of England until the underwhelming conclusion rolls back onto the page, and you can put down the book, and breathe a hearty sigh of relief.
I am sorry to say that in the case of George Johnson’s book The Ten Most Beautiful Experiments the afterword, tantalizingly titled “The Eleventh Most Beautiful Experiment,” proved not only underwhelming, but also confusing and disturbing. I shall save you the trouble of flipping to the back of the book; the key problem lies in the first paragraph of Johnson’s approximately one-page afterword:
In the autumn of 2006, while I was science writer in residence at the Kavli
Institute for Theoretical Physics in Santa Barbara, California, I gave a talk on The Ten Most Beautiful Experiments. Afterward a woman came forward to ask why there would only be men in the book.
The woman’s question is, I think you will agree, a perfectly reasonable one. In a book presenting not ten but the ten most beautiful experiments (we will get to the problems with Johnson’s definition of “beautiful” shortly), a book that spans more than four hundred years, why not include, say, one woman? One would, after all, be fairly representative of the perceived role of women in the sciences for at least the 1600s to the mid-1900s. Why no women, then?
I’d thought of including Marie Curie for her discovery of radium…. But that struck me as more of a heroic exploration than a controlled interrogation of nature. Lise Meitner seemed a likelier candidate, but her pioneering experiments in nuclear fission in the late 1930s were done with Otto Hahn and Fritz Strassman. Science was already becoming the collaborative effort that it is today.
Somehow, the two obvious women candidates don’t jive with Johnson’s desire to talk about “controlled interrogation[s] of nature.” As for straying from the “collaborative effort,” we may choose, along with the author, to disregard the fact that in previous chapters just such collaborations (between Robert Millikan and his doctoral student Harvey Fletcher; and the Michelson-Morely experiments seem to have been a joint effort) were described in great detail.
What about other women, then? Johnson lists a few – Rita Levi-Montalcini, Barbara McClintock, and Chien-Shiung Wu – before lamenting, “I’ve barely finished the book and already I’m second-guessing myself.” Then come more men (and one woman) Johnson might have included: James Chadwick, Gregor Mendel, Alfred Hershey and Martha Chase, and Watson and Crick (sadly, few remember Rosalind Franklin, whose pioneering X-ray work paved the way for the discoveries Watson and Crick made).
All right. Now Johnson has the perfect opportunity to explain himself, to lay out in great detail his criteria for selecting certain experiments. So many more might have made the cut: why didn’t they?
Alas, the reader finds no rationale:
As the twentieth century wears on, the pickings grow slimmer, with nature holding tightly to what secrets remain…But you never know. The eleventh most beautiful experiment may be yet to come.
Such side-stepping is indicative of a broader difficulty with Johnson’s book. (And well we may wonder about the “slim pickings” of the human genome project, advances in AIDS treatments, or post-Einstein work on subatomic particles, to name an obvious few of the efforts of modern science.) I point out the unanswered question regarding women experimenters because it seems to me the most blatant. Johnson’s “Prologue” demonstrates a similar aversion to answers:
Likelier than not, anyone who reads this book could come up with a different list. ‘Shouldn’t you just call it Ten Beautiful Experiments?’ a friend objected. Probably so. But I hope that there is art in the arbitrariness, both in my selection of the experiments and in what I have chosen to tell about each one.
Certainly Johnson’s selections and choices are arbitrary, but I can’t agree that there is art in such randomness. In fact, in 2003, Robert Crease published The Prism and the Pendulum: The Ten Most Beautiful Experiments in Science, which not only covers much the same ground as The Ten Most Beautiful Experiments, but avoids Johnson’s milquetoast ecumenicalism and argues forcibly for the preeminence of its subjects. Crease, moreover, places his chosen experiments within the continuum of history; in contrast, Johnson seems to make a point of arbitrariness.
At the very least the reader needs a reason for the inclusion of William Harvey (who described the circulation of blood) and Ivan Pavlov (who explored the phenomenon of conditioning), who seem rather out of place in a group of scientists like Luigi Galvani, who, along with Alessandro Volta, teased out the secrets of electricity and bioelectricity; Michael Faraday, whose experiments revealed truths about electromagnetism; Albert Michelson, of Michelson-Morely experiment fame, which proved that aether did not exist; and Robert Millikan, who measured the charge on the electron.
Of course, what relates Galvani, Volta, Faraday, Joule, Michelson, and Millikan is a narrative, of the discoveries crucial to the understanding of quantum mechanics and special relativity. There does exist an accumulation of knowledge that each researcher, as well as myriad others working towards similar ends, made use of – that knowledge was not gained in a straightforward linear fashion, of course, but such work at least cohered and had, all told, a general trajectory. Johnson makes a few stabs in describing this; for example, he notes that the mid-eighteenth century “was the height of the romantic era in electrical research, with scientists debating whether electricity was a vapor, a fluid, or, as Benjamin Franklin speculated, ‘subtle particles.’” Tangled up with the problem of electricity was the problem of light, itself potentially wave or particle, and as science approached the twentieth century, potential solutions to these problems (i.e., electricity is produced by charged particles, and light shows characteristics of both waves and particles) would open up further problems, which it then became the work of quantum mechanics to try to answer.
Galvani’s experiments with frog legs and Volta’s with electrical piles led to solutions that appeared at odds with one another, as Johnson points out:
Though neither man could quite see it, their experiments complemented each other, for they were dancing around a single truth. Natural, artificial, animal – electricity is electricity. Volta didn’t appreciate that what he was observing with his “contact electricity” [that is, the voltage produced when he created stacks of alternating copper and zinc discs separated with salt-water-soaked cardboard spacers] was a chemical reaction…and Galvani clung to the idea that there was something inherently different about biological electricity [the sort he produced when he touched the sciatic nerve of a frog’s leg].
James Clerk Maxwell built on the experiments of Faraday’s which Johnson also describes. Faraday found that magnetic fields could rotate polarized beams of light, and Maxwell demonstrated “with his famous equations that light is electromagnetism.” Michelson and Morely utilized these ideas about the relationship between light and electromagnetism, which in turn enabled Millikan’s experiments.
It would have taken more work and more thought on Johnson’s part to write an expanded version of the two paragraphs above, but it would have been worth the effort, because having some clear notion that these experiments were moving in a direction, were moving forward, albeit messily and with many setbacks, would have made for a more satisfying read than merely a hodgepodge of descriptions of the physical nature of the experiments themselves. By describing his experiments in relative historical isolation, Johnson loses sight of the importance of the accumulation of knowledge to the scientific method. As Newton famously remarked, all scientists stand on the shoulders of the greats who preceded them: to fail to connect their experiments is to misrepresent them.
What might explain Johnson’s timidity? In part, I think, he is unclear about whom he intends his audience to be. One of the difficulties with books falling under the class of “popular science” is the sad fact that not everyone who reads them will have the same level of scientific knowledge or investment. As an author, then, how do you decide what your audience knows out of hand, and what it might reasonably be expected not to know?
Johnson seems to have settled on a kind of mash-up of ideas that a piker would easily recognize and those that are far more technical and abstruse. Well and good. One must be selective, after all. Johnson is, as I said, far more invested in describing the set-ups, the schematics, the devices of the experiments than in spending much time on their historical significance. But often these descriptions feel clunky or inelegantly executed, anything other than beautiful. For instance, here Johnson delineates the setup of the Michelson-Morely experiment:
The pieces [of equipment] were mounted on a sandstone slab, about five feet square and fourteen inches thick, which was attached to a wooden buoy, shaped like a doughnut and floating in a cast-iron trough of mercury. The trough itself was set on a concrete bed atop a brick platform. Four metal mirrors were set at each corner to reflect the light from an Argand lamp back and forth, increasing the path lengths – the one going with the Earth and the other moving across – to thirty-six feet. A wooden cover protected the optical instruments from the air.
Johnson provides a diagram on the opposite page, but the picture fails to illuminate much about the reasoning behind certain parts of the experiment – would the average reader of this book know off-hand why mercury was important, or what an Argand lamp was, or why the light rays had to move “with” and “across” the Earth? Nor do many of the illustrations redeem the dryness of Johnson’s descriptions. Mercury plays a different, but also unexplained, role in Lavoisier’s experiment, in which “four ounces of pure mercury” were poured into a bottom chamber and set “on a furnace with the neck dipping down into an open trough, also filled with mercury, and then up into a bell jar. This would serve as a gauge to measure how much air was consumed during the experiment.” The layperson is likely to come away from The Ten Most Beautiful Experiments with the vague sense that mercury is some sort of magical elixir, and that these experiments may be quite refined and impressive, maybe even beautiful, but still fundamentally inscrutable.
Yet the questions arises, are the experiments beautiful? What would make them so? Indeed, what does it mean to think of science as being beautiful – does science have an obligation to conform to aesthetic standards? Anyone who has ever worked in or walked through a lab would be hard-pressed to find anything beautiful about most experimental setups: while some rigor in organization is always called for, probes, pipettes, notebooks, notes, computers, chemicals, and beakers aren’t elegant unless a concerted effort is made to force them to be so. Science requires its experimenters to get their hands dirty, whether with oil or blood or statistics, and the experiment often becomes a mad rush of data points, equipment springing out of alignment, or test subjects failing to show up (or, as in the case of the monkey with whom a neuroscientist friend of mine was working, test subjects dying).
Scientific beauty lies more in the solutions, the applications, the rendering of information, than in the experiments themselves – or else the experiment is beautiful on its conceptual level rather than in its execution. It is groundwork or interpretation where beauty enters the scene. History tends to scrub its experiments clean, to reduce the failures to footnotes and the institutional bickering (where does the funding for experiments come from, anyhow? and who gets to take credit for the work?) to differences of opinion. It is incredibly easy to forget that each successful experiment requires a multitude of accidents, arguments, research, theorizing, reframing, and interpreting. In the act, true beauty is scant.
So what is a beautiful experiment? Johnson’s answer conforms more to a steampunk sensibility than to hard and fast criteria:
What I was looking for were those rare moments when, using the materials at hand, a curious soul figured out a way to pose a question to the universe and persisted until it replied. Ideally the apparatus itself would be a thing of beauty, with polished wood, brass, shining black ebonite.
According to such a description, we might easily find the included experiment by Galileo beautiful – in which he proves that a falling body accelerates at a constant rate, so that the distance the body falls increases with the square of the time in which the body has fallen; in other words, as Johnson puts it, “the steeper the slope, the faster the ball would roll.” Galileo employs a brass ball running down a smooth wooden ramp, with time measured according to a water clock. True, no ebonite here, but it fits the general picture.
Yet would we necessarily find Harvey’s or Galvani’s experiments beautiful? In Harvey’s case, he vivisects a snake and pinches arteries above and below its heart to prove his theory of the circulation of blood: “Using a forceps or thumb and finger,” Johnson explains, “pinch the main vein, the vena cava, just before it enters the heart. The space downstream from the obstruction quickly empties of blood. The heart grows paler and smaller, beating more slowly.” Pinching the artery after it leaves the heart makes the heart distend. In so doing you are tying off part of a circle, Harvey reasoned. In Galvani’s case, frog legs and lightning bolts figure prominently: string a lead from a tall metal pole to a metal probe, touch the probe to the exposed nerve of a disembodied frog leg, and wait for lightning to strike, at which point, as Frankenstein’s monster, so goes the frog leg. Even Pavlov, who was concerned with the ethics of his work, collected saliva from dogs who had had their salivary glands rerouted to leak outside their mouths. It isn’t easy to determine how these gruesome examples can be called beautiful. But then, why should they be? Does it serve us as readers and as students to have boring, sanitized descriptions of such studies? Blood and guts were flying around! Surely that would wake up a sleepy reader.
Johnson provides us another criterion for a beautiful experiment: “More important would be the beauty of the design and the execution, the cleanness of the lines of thought.” This is at best a debatable point. (I doubt PETA would agree.) Johnson himself concedes the subjectivity of his arguments, as we have seen. Why does he not spend more time, then, articulating what is beautiful about the design, execution, and lines of thought involved in each experiment? Instead we have each experiment announced as “beautiful,” a sad and lazy tautology from a writer who could have given us so much more to ponder.
It is worth noting that, despite the book’s title, The Ten Most Beautiful Experiments is far less about the experiments than about the scientific minds which realized such experiments. Particularly bothersome is Johnson’s tendency to meander through side-stories which are admittedly interesting – it would be a dry book indeed without some of the color his meanderings provide – but which leave little room for a detailed description of the beautiful experiment itself. Pavlov’s case is the worst offender, garnering a mere three quarters of one page:
Pavlov and his collaborators had already shown that a dog had basic musical abilities. Trained to salivate to a specific chord, say A-minor, it would also react – albeit more weakly – to each individual note. Pushing still further, the researchers began testing the animal’s ability to recognize simple melodies.
When four notes were played in ascension, the dog was given a bit of food. When the same notes were played in the descending order, there was no reinforcement.
The animal learned to tell one sequence from the other. But how, Pavlov wondered, would it respond when it heard the twenty-two other possible combinations of the same notes?
The melodies were played and the spittle collected. The dog had categorized the scales into two equal groups depending on whether the pitches were predominantly rising or falling. It’s not too much of a stretch to say that the animal had formed a rudimentary concept. This kind of pattern recognition, Pavlov came to believe, was the root of what he himself did as an experimental scientist.
Johnson has set the scene, but again this comes to a question of readership: does the general audience, the one likely to pick up and read this book, have at least a rough sense of what Pavlov’s experiments were all about? Johnson seems to think so: noting that the dogs could be trained to salivate at flashing lights, hot or cold pokes to the skin, a whistle, a horn, he points out in a parenthetical aside that “Pavlov hardly ever used a bell.” This may be the first thing that comes to mind when you think of Pavlov (it was for me), but it hardly constitutes meaningful information. Elsewhere we learn that Pavlov named and was close to each of his dogs (presumably before he mutilated them); that Lavoisier’s wife illustrated his work, and after his death she presided over a scientific salon; and that Johnson himself has replicated Millikan’s oil drop experiment. The effect of all these quiz-show tidbits is to reduce the importance of the experiments to the level of trivia.
That is perhaps the key problem with this book: it is about 160 pages long. Crunching the numbers, that means each experiment (rather experimenter) gets about 16 pages, including illustrations. The reader will likely feel that Johnson could have spared each chapter a few more pages, at the least, because The Ten Most Beautiful Experiments leaves one with nothing so much as a longing for more detail, more time, more words.
For Johnson’s prose is engaged; the book displays his passion for the work, and it would be hard to come away from The Ten Most Beautiful Experiments without feeling at least slightly entertained and inspired. The vision of the book it could have been is briefly glimpsed in Johnson’s chapter on Robert A. Millikan, who measured the charge on a single electron by measuring the force on charged droplets of oil suspended against gravity between two metal electrodes. It is in Millikan’s work that Johnson finds the most beauty, and the reader will too, in Johnson’s pure, almost childlike, excitement in describing his replication of the procedure.
Johnson describes a trip to a lab where a physicist has set up Millikan’s experiment, which essentially employs light, oil drops, and electromagnets:
When the setup was complete and the room darkened the experiment began. After several trial runs Mr. von Briesen invited me to take a look. Gazing into the chamber through a magnifying eyepiece – a little telescope – I saw the droplets. Illuminated from behind, they shone like a constellation or galaxy.
And, indeed, this is how Millikan has seen them too, who wrote:
I saw a most beautiful sight…. The field was full of little starlets, having all the colors of the rainbow. The larger drops soon fell to the bottom, but the smaller ones seemed to hang in the air for nearly a minute. They executed the most fascinating dance.
Perhaps the true beauty lies not only in the construction of the experiment or the lines of reasoning with which the experimenter works, but in the execution of the experiment itself, the wonder that only a living demonstration of human knowledge can impart. True beauty seems fleeting in Johnson’s book. If does exist there, the reader will require much statistical analysis to determine its extent and meaning.
Lianne Habinek is a Phd candidate in English literature at Columbia University. She is working on a dissertation about literary metaphor and 17th-century neuroscience.