The Story of Western Science

by Susan Wise Bauer

  Bacon had laid the foundation for the modern scientific method, but Boyle’s use of instruments and helps truly brought the experimental phase of modern science into being. The Sceptical Chymist’s place in history is assured not by its conclusions, but by its procedures; not by the truth it discovers at the end, but by the road it takes to get there.

  •

  In 1662, the year after The Sceptical Chymist’s publication, Boyle’s lab assistant Robert Hooke acquired a new job: curator of experiments for the fledgling Royal Society of London.†

  Since the 1640s, as Boyle’s early reference to the “invisible college” reveals, small groups of natural philosophers had been meeting informally in both London and Oxford: “They had no Rules nor Method fix’d,” says Thomas Sprat, the first historian of the Royal Society, “[and] their intention was more . . . to communicate to each other . . . their discoveries . . . than a united, constant, or regular inquisition.” This lack of structure fitted the chaotic, uncertain years of the English Commonwealth: a time when the English government was turned onto its head, when Boyle was best off researching quietly, and privately, away in his self-funded lab.‡

  But Oliver Cromwell, prime mover and lord protector of the commonwealth, died in 1658; Charles II returned triumphantly to his throne, and the traditional English hierarchies were restored. Six months after Charles II’s recoronation, the Royalist scholar Christopher Wren—architect, astronomer, and physicist—chaired the first meeting of the newly formed “College for the Promoting of Physico-Mathematical Experimental Learning” in London. By 1662, the “college” had been granted a charter by Charles II and renamed the Royal Society of London.19

  Now a royally favored institution, the Royal Society suddenly grew; in fact, its nonscientific fellows soon outnumbered the natural-philosopher types. Hooke’s appointment as curator of experiments seems to have been intended to keep the group on track. He was paid a full-time stipend to do two things: present a variety of weekly experiments to the gathered Royal Society, explaining and demonstrating as he went; and assist the fellows with their own experiments, as needed.20

  This paid position made Robert Hooke (probably) the first full-time salaried scientist in history. The Royal Society was made up of astronomers, geographers, physicians, philosophers, mathematicians, opticians, and even a few chemists, so Hooke was called on to experiment and research across the entire field of natural philosophy. The broad scope of the position suited him perfectly. His laboratory work with Boyle had touched only the surface of his abilities. He was an excellent mathematician (which Boyle was not), expert at grinding and using lenses, inventor of a barometer, founder (in some sense) of the modern study of meteorology, a competent geologist and biologist, architect and physicist.

  The experiments that Hooke presented to the Royal Society, in its weekly meetings, stretched across the range of his abilities. One set of demonstrations, recorded by Thomas Birch, began with an experiment showing how fluids reach hydrostatic balance, continued with a Parisian method for waterproofing calf hide by soaking it in “salad oil,” and concluded with the presentation of a “sort of Portugal onion” that all examined with interest, since “none of the like” had been seen before.21

  Further experiments involved pendulums, distilled urine, insects placed in pressurized containers, observations through colored and plain glass, and the weight of water. But increasingly, Hooke’s experimental demonstrations made use of the microscope.

  The first work of natural philosophy to utilize the microscope had been published, some forty years earlier, by Federico Cesi, Galileo’s correspondent in Rome. Called Apiarium, it was a thorough study of the habits of bees; Cesi had used microscopic observations both to confirm Aristotle (“Just as Aristotle wrote, so [we] saw and observed that they . . . carry away their pollen with these hairs”) and to occasionally contradict him. Other microscopic studies had been done by Cesi’s colleagues, and the lens technology had been slowly improving.22

  Hooke was particularly interested in the microscope. Like his mentor Boyle, he believed that natural philosophy needed instruments: “By the addition of such artificial Instruments and methods,” he wrote in 1664, “there may be, in some manner, a reparation made for the . . . infirmities of the Senses”:

  Some parts of [Nature] are too large to be comprehended, and some too little to be perceived. And from thence it must follow, that not having a full sensation of the Object, we must be very lame and imperfect in our conceptions about it . . . hence, we often take the shadow of things for the substance, small appearances for good similitudes, similitudes for definitions. . . . [The] care to be taken, in respect of the Senses, is a supplying of their infirmities with Instruments, and, as it were, the adding of artificial Organs to the natural. . . . By the help of Microscopes, there is nothing so small, as to escape our inquiry; hence there is a new visible World discovered to the understanding.23

  Hooke had been demonstrating this “new visible World” to the fellows, and they were appreciative of his advances. In April of 1663, the minutes of the Royal Society note, “Mr. Hooke was charged to bring in at every meeting one microscopical observation at least.” At the very next meeting, Hooke “showed the company” what moss looks like under magnification. “He was desired to continue,” the minutes explain; and over the course of the next few months, Hooke demonstrated the microscopic structures of cork, bark, mold, leeches, spiders, and “a curious piece of petrified wood” belonging to one of the fellows, a Dr. Goddard.24

  Dr. Goddard had asked him to examine and report on this odd specimen, and Hooke duly carried out his duties. The petrified wood, he wrote, resembled living wood in its pores and structure, but was as hard and impenetrable as rock. And then Hooke offered an explanation:

  The reason . . . seems to be this: that this petrified wood having lain in some place, where it was well soaked with petrifying water (that is, such a water as is well impregnated with stony and earthy particles) did by degrees separate, by straining and filtration, or perhaps by precipitation, cohesion, or coagulation, abundance of stony particles from that permeating water; which stony particles . . . conveyed themselves . . . into the pores. . . . By this intrusion of the petrified particles, it also becomes hard and friable . . . the smaller pores of the wood being perfectly stuffed up with the stony particles.25

  He had gone beyond observation with instruments, beyond the disproving of current theories, to something new: the establishment of a new physical process that he had not seen (and could not see), but that he was able to deduce. He had described, for the first time, the process of fossilization, and in doing so had contradicted the received wisdom—that fossils were nonorganic forms, produced and made out of rock.

  This was the next step in the use of instruments and helps: using these closer observations, the extension of the senses through artificial means, as the launching place for new ways of thinking. Not only the senses, but also the reason, were augmented by these instruments and helps. The true end goal of the microscope and telescope, the air pump and the vacuum chamber, was not merely observation; it was observation that led to new theories, observation that allowed man’s mind to range farther afield than ever before.

  In 1664, the Royal Society formally requested that Hooke print his micrographic observations. On top of his other competencies, Hooke was a skilled draftsman and artist. Rather than merely describing his discoveries in words, or commissioning nonscientists to produce his drawings, he made his own: large, exquisitely detailed, and perfectly clear.

  The resulting work, Micrographia, was published in 1665. The first fifty-seven illustrations and observations are microscopic; the last three, of refracted light, stars, and the moon, are telescopic. The quality of the illustrations was light-years ahead of anything that had been seen before, and the book was an instant sensation.

  But although the eye-grabbing pictures attracted the most attention, even more notable is that, throughout, Hooke uses his newly extended senses
to build new theories. After carefully examining the colors and layers of muscovite (“Moscovy-glass”), he goes beyond his observations to suggest nothing less than a theory of how light works: it is, he speculates, a “very short vibrating motion” propagated “through an Homogeneous medium by direct or straight lines.”26

  Like his theory of fossilization, this model could not be directly proved. But Hooke was merely carrying out the method he had laid out in Micrographia’s “Preface.” It was not enough merely to extend the senses by way of instruments; reason must follow the path laid out by these observations, interpret them, and then check itself again. Using William Harvey’s circulatory system as his analogy, Hooke explained that true natural philosophy

  is to begin with the Hands and Eyes, and to proceed on through the Memory, to be continued by the Reason; nor is it to stop there, but to come about to the Hands and Eyes again, and so, by a continual passage round from one Faculty to another, it is to be maintained in life and strength, as much as the body of man is by the circulation of the blood through the several parts of the body, the Arms, the Feet, the Lungs, the Heart, and the Head. If once this method were followed with diligence and attention, there is nothing that [does not lie] within the power of human Wit. . . . Talking and contention of Arguments would soon be turned into labours; all the fine dreams of Opinions, and universal metaphysical natures, which the luxury of subtle brains has devised, would quickly vanish, and give place to solid Histories, Experiments and Works. And as at first, mankind fell by tasting of the forbidden Tree of Knowledge, so we, their posterity, may be in part restored by the same way, not only by beholding and contemplating, but by tasting too those fruits of natural knowledge, that were never yet forbidden.27

  Instruments and helps were no longer merely extensions of the senses; they had become, for Hooke, the Tree of Knowledge, the path to perfection.

  To read relevant excerpts from The Sceptical Chymist and Micrographia, visit http://susanwisebauer.com/story-of-science.

  ROBERT BOYLE

  The Sceptical Chymist

  (1661)

  The Sceptical Chymist is not an easy read (“prolix, repetitive, disjointed, and occasionally contradictory,” in Lawrence Principe’s words).28 However, the Preface, Physiological Conditions, and First Part give an excellent overview of Boyle’s preoccupations and his commitment to experimentation.

  Robert Boyle, The Sceptical Chymist: The Classic 1661 Text, Dover Publications (paperback and e-book, 2003, ISBN 978-0486428253).

  ROBERT HOOKE

  Micrographia

  (1665)

  Although multiple reprints of the Micrographia are available, few of them reproduce Hooke’s groundbreaking illustrations at the original size or with decent detail. The best way to view the illustrations is in the Octavo CD, which offers clear scans of the actual pages of the original book, in PDFs that can be magnified, rotated, and viewed in color or black and white.

  Robert Hooke, Micrographia, Octavo Digital Rare Books (CD-ROM, 1998, ISBN 1-891788-02-7).

  However, the text itself (complete with unmodernized spelling) is extremely difficult to make out in the Octavo scans. Consider turning to one of the free e-book versions (such as that found at Project Gutenberg) or a paperback reprint in order to read Hooke’s accompanying essays—particularly the Preface, in which he explains the relationship between the senses and the faculty of reason.

  Robert Hooke, Micrographia, Project Gutenberg (e-book, 2005).

  Robert Hooke, Micrographia, Cosimo Classics (paperback, 2007, ISBN 978-1602066632).

  * * *

  * Cups made of bone-ash, used to combine molten metals.

  † The early history of the Royal Society of London is somewhat obscure and is also much debated. The accuracy of the earliest account, Thomas Sprat’s The History of the Royal Society of London (1667), has been challenged in recent years; Michael Hunter’s Establishing the New Science: The Experience of the Early Royal Society (Boydell Press, 1989) offers a lively and useful survey of the evidence.

  ‡ The English Commonwealth (1649–60) was a brief and violent departure from the tradition of English monarchy. Parliamentary leaders, including the Puritan Oliver Cromwell, led a revolt against King Charles I that ended in the arrest, trial, and shocking execution of the sovereign. A nominally republican government took Charles I’s place; within four years, Cromwell managed to seize personal control of England under the title “Lord Protector.” The Commonwealth ended ignominiously with Cromwell’s death, after which Charles I’s exiled son and heir was invited back to the throne.

  TWELVE

  Rules of Reasoning

  Extending the experimental method across the entire universe

  Those qualities of bodies . . . that belong to all bodies on

  which experiments can be made should be taken as qualities

  of all bodies universally.

  —Isaac Newton, Philosophiae naturalis

  principia mathematica, 1687/1713/1726

  Five years after the publication of the Micrographia, at the December 21, 1671, meeting of the Royal Society, Robert Hooke (still curator of experiments) presented a new method of musical notation and proposed an experiment measuring the force it would take to make mercury pass through wood. Robert Boyle, also in attendance, described an experiment showing that “air will flow where water will not.” And a new candidate for membership was proposed: one “Mr. Isaac Newton, professor of mathematics in the University of Cambridge.”1

  Isaac Newton was twenty-nine years old, Cambridge educated, and for the prior four years had been a teaching fellow at Trinity College, his alma mater. He was duly elected at the January 1672 meeting, where “special mention was made of Mr. Newton’s improvement of telescopes”; Newton had sent the Royal Society one of his improved instruments, with his compliments.

  Newton was, like Boyle and Hooke, a user of artificial helps, a mathematician who was also anxious to extend his senses in the pursuit of truth. In the February meeting, the ink on his membership certificate barely dry, he submitted to the society a letter describing his most recent “philosophical discovery”:

  that light is not a similar, but a heterogeneous body, consisting of different rays, which had essentially different refractions, abstracted from bodies through which they pass; and that colours are produced from such and such rays, whereof some, in their own nature, are disposed to produce red, others green, others blue, others purple . . . and that whiteness is nothing but a mixture of all sorts of colours, or that it is produced by all sorts of colours blended together.2

  Newton had been working not with scopes, but with prisms: instruments that distorted (“tortured”) natural light into revealing its component parts.

  In his letter, Newton characterized his discovery on light as “the oddest, if not the most considerable detection, which hath hitherto been made in the operations of nature.” This immodest claim immediately produced an equal but opposite reaction. The Royal Society “solemnly thanked” Mr. Newton for his discoveries and commissioned Hooke to produce an answer; Hooke fired back that he could “see no necessity” in Newton’s proposal. It went directly against the commonly received wisdom that light was white, and homogenous. Passing it through various substances (such as transparent layers of stone, as in an experiment that Hooke had documented in Micrographia) merely modified it so that it turned different colors. Hooke conceded that Newton’s new explanation might be true, but he insisted that it had no greater probability of truth than the existing theory; Newton, he objected, had not provided “an absolute demonstration of his theory,” and Hooke declined to be convinced. Later that year, he duplicated Newton’s experiment for the Royal Society, “confirming what Mr. Newton had said,” but he continued to argue that “these experiments were not cogent to prove that light consists of different substances.” He could think of at least two other “various hypotheses” that could equally well explain Newton’s results.3

  It was the beginning of a conten
tious relationship between the two men. The enmity grew partly out of a natural clash between two highly competent and ego-driven personalities, and partly out of a difference in philosophy. Hooke, along with most of the leading members of the Royal Society, was entirely committed to the experimental method, but wary about drawing universal conclusions from it. The society was intrigued by Newton’s “theory of light” but recommended that many more experiments be carried out before any conclusions could be drawn. These experiments dragged on for the next three years, with much correspondence flying back and forth between Newton’s Cambridge elaboratory and the Royal Society’s London headquarters.

  By 1675, Newton was growing exasperated. He sent a much more elaborate manuscript to the society, laying out a more detailed explanation about his experiments and what they revealed about light movement through the “ether.” On December 16, Hooke presented this manuscript to the Royal Society: “After reading this discourse,” the minutes tell us, “Mr. Hooke said that the main of it was contained in his Micrographia, which Mr. Newton had only carried farther in some particulars.”

  Newton, unsurprisingly, took offense and, in return, accused Hooke of “borrowing” a little too freely from other thinkers, including both René Descartes (who had published his Discourse on Method forty years earlier) and Newton himself. The spat between the two grew sharp and public. More letters were exchanged, and more experiments proposed. Newton became increasingly frustrated—partly by Hooke, but mostly by the Royal Society’s continuing demands for more proof. In 1676 he observed tartly in a response to the society itself, “It is not number of experiments, but weight, to be regarded; and where one will do, what need many?” And he wrote bitterly, to a colleague, “I see that a man must either resolve to put out nothing new, or to become a slave to defend it.”4

  Gradually, Newton withdrew from participation in the Royal Society’s agenda. His name appears less and less often in the minutes. Rather than participating in the unending experiments curated by Hooke and demanded by the society’s fellows, Newton devoted himself to his own research: not only on light and optics, but also on the orbits of the planets and the celestial mechanics that might explain them. Twelve years after his fracas with Hooke, he published his first major work: Philosophiae naturalis principia mathematica, or “Mathematical Principles of Natural Philosophy.”