Robert Hooke

In May 1676, London's upper crust headed to the theater to see playwright Thomas Shadwell's newest work: The Virtuoso. The play's central character, Sir Nicholas Gimcrack, had spent 2,000 pounds on microscopes to learn about "the nature of eels in vinegar." He had transfused sheep's blood into a madman who then bleated like a lamb, observed military campaigns on the Moon and read his Bible by the light of a rotting leg of pork (some savants had recently discovered the phenomenon of bioluminescence). Shadwell's play took a swipe at all London's 17th-century savants, but the central character bore particular resemblance to one individual: Robert Hooke, longtime curator of experiments for the Royal Society of London. Tipped off by his coffeehouse buddies that he was probably the butt of Shadwell's jokes, Hooke went to see the play for himself. A more jovial man than Hooke might have laughed along with the crowd at his own expense. A more modest man might have doubted whether the play was necessarily about him. But Hooke was neither jovial nor modest. He was livid. "Damned Dogs," he wrote in his diary. "People almost pointed."

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Fossil wood illustration from Micrographia by Robert Hooke
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Ammonite illustrations from London's Leonardo by Bennett, Cooper, Hunter and Jardine

Shadwell had a razor-sharp wit, and he had something of a point. In its early days, the Royal Society above all valued the rare and weird. World-class science would come many years later, but in the society's early, spectacle-fixated days, Hooke managed to advance science on several frontiers, paleontology and biology being just two of them.

Hooke was born on the Isle of Wight in 1635. He was the baby of the family and his health was delicate, so his parents tutored him at home instead of sending him off to boarding school at a tender age. He likely spent some of his free time walking along the beaches and perhaps collecting the odd seashell or fossil. His calm world began to crumble with the fall of King Charles I. England's Civil War and the rule of Oliver Cromwell followed — rough times for a royalist like Hooke. His father died when Hooke was just 13, and the boy moved to London with a modest inheritance, enough to keep him afloat until he found employment. He quickly impressed his elders with his keen observational and mechanical skills. After a brief apprenticeship with a portrait painter, he enrolled in the Westminster School then moved on to Oxford. He became a lab assistant first to Thomas Willis, then to Robert Boyle, and eventually became a professor at Gresham College, London. He served as a city surveyor and an invaluable assistant to his lifelong friend, Christopher Wren, in rebuilding London after the Great Fire of 1666. Like Wren, Hooke endured lean years before the Restoration of Charles II. Afterwards, both men rebounded, but Hooke never achieved the same level of recognition or financial stability as his more famous friend. He did, however, work with Wren and others to establish the Royal Society of London (science's most elite club at that time and still enormously prestigious today), where he became the society's curator of experiments and eventually a member of its governing board.

In the 17th century, most savants believed that fossils were made by "plastick virtue," a creative force within the Earth capable of fashioning any shape out of stone. Hooke accurately observed that, depending on where they were found, fossils varied in hardness and color, and also noted that while some fossils were complete and pristine, others were badly broken. Perhaps the first person to use a microscope to examine the origin of fossils, Hooke identified microscopic "snail" shells, though he didn't give then the modern name of forminifera.

Fossils gave Hooke another learning opportunity in the form of petrified wood. Ancient wood collected by the Lincean Academy in the early 17th century was eventually relayed to Hooke for study. By repeatedly soaking and drying it or exposing it to flame (both methods worked) he exposed pores similar to those of living specimens. Hooke recorded the similarities and differences between modern and petrified wood, and explained those similarities and differences with a description of the petrifaction process still respected by scientists today. He rejected the "plastick virtue" hypothesis. As he put it, "Nature does nothing in vain."

For all Hooke learned from fossil wood, however, the shells of modern and extinct cephalopods may have had an even greater impact on his views. Hooke saw how much the modern nautilus and the extinct ammonite resembled each other. He didn't just observe the physical appearance of these animals; he also experimented on the fossil ammonites, showing that the thin walls between their chambers could dissolve in acid, just like modern shell material. Yet Hooke also saw the differences between smooth-shelled nautiluses and corrugated-shelled ammonites, and this raised a nagging question: Where were the ammonites now?

That any of God's creations could perish from the Earth was untenable to 17th-century natural philosophers. Cuvier was more successful in promoting the concept of extinction in the late 18th and early 19th century, perhaps because the Enlightenment and French Revolution had made society — or at least some savants — more willing to accept unorthodox ideas.

As for Hooke, he recognized that geological processes could petrify fossils, and transform the crust of the Earth itself. He came under fire from many of his contemporaries for his radical ideas. He reminded his colleagues that they had observed changes within their own lifetimes. Why couldn't the Earth change even more on a larger time scale? (Science historian Martin Rudwick contends that the larger time scale Hooke was thinking of could still be measured in just several thousand years, as was commonly believed in the 17th century.) But Hooke's most provocative insights about fossils weren't published until after his death.

As a curator of experiments, Hooke may have been one of the first people to "curate" in the modern sense, i.e., oversee a collection. As an experimenter for the Royal Society, he participated in some of the 17th century's most important discoveries about physiology, though his methods now seem pretty shocking. He deprived several animals of air to see the results — namely that the animals went into convulsions and then died. He conducted an experiment to observe the beating heart and inflating lungs of a dog while the animal was still alive. When asked to repeat the experiment, he refused, citing "the torture of the creature." Yet he later carried out experiments that deprived dogs of fresh air, and it was through these experiments that he learned the importance of oxygen. Hooke's methods were often cruel, but his discoveries were important, and he didn't have many other options for learning what those experiments told him.

In between experiments involving hapless animals, Hooke set new standards in instrument design. Behind his lifelong quest to develop observational instruments like the microscope and the telescope were his religious convictions. Using the best instruments, he believed, people could regain the perfect senses that humanity had lost after the expulsion from Eden. He mused that mechanical inventions might "improve our other Senses, of hearing, smelling, tasting, touching."

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Title page
Flea illustration and title page from Micrographia by Robert Hooke
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Kettering stone from Micrographia by Robert Hooke

By the time he started tinkering with microscopes, they had been in use for decades. Yet working in the field as early as he did, Hooke may have been the first person to see such a magnified view of much of what he studied: the surprisingly blunt tip of a needle, the minute-mushroom shape of mold. Before the 19th century, the world's most powerful microscope was the tiny single-lens microscope. Hooke may have been the first person to make one of these, and he was the first to describe its manufacture. Through a single-lens microscope, one could see objects so tiny they truly were invisible to the human eye, but the device strained Hooke's own eyes. Moving on to the compound microscope, he left it to the Dutch microscopist Leeuwenhoek to discover things like bacteria. In fact, Hooke may have left more to Leeuwenhoek than he realized; a 2021 study used neutron tomography to examine the shape of Leeuwenhoek's powerful lenses and found a remarkable resemblance to the "exceeding easie to make" ball-shaped lenses Hooke described in 1678.

Good microscopic observations require adequate light, but when Hooke started using microscopes, no one had figured out a satisfactory method for providing it. In his own observations, he discovered that, depending on the light source, a fly's eye might resemble a lattice, or a surface covered with pyramids, cones or "golden Nails." He eventually learned to amplify light to his microscope by placing a brine-filled glass globe between the light source and the microscope. He called this invention the scotoscope.

Some modern researchers have been skeptical of how much Hooke could really see through his microscopes. A televised attempt at recreating his observations resulted in such poor quality magnification that one might as well use a naked eye. But Brian Ford, who specializes in the history of microscopy, defended Hooke's reputation. The microscopes of Hooke's day were indeed difficult to use, but Ford found that careful adjustments of light and focus reveal the same level of detail as Hooke documented.

In 1665, Hooke shared his new views of tiny things in his book Micrographia. Noted diarist Samuel Pepys ordered a copy, stayed up reading it until 2 a.m., and characterized it as "the most ingenious book that ever I read in my life." It wasn't the first book about the microscope; Pierre Borel beat him with a slim volume, but Micrographia was far more substantial, and a best seller that had to be reprinted in two years. It was only the second book published under the imprimatur of the Royal Society. Hooke wasn't yet 30.

Hooke actually took over Micrographia from Wren, whom he credited for the original work. Many of the illustrations were, if not Wren's own work, certainly inspired by his drawings. Micrographia covered the newly magnified terrain of flies, fleas, fossils, fungi, fish scales, razor blades, snowflakes, stinging nettles, lice plucked from his own head, Kettering stone and bodily fluids. On many occasions, he found objects of human invention — the uneven splotch of a magnified printed period, for instance — far inferior to the intricate work of nature. The details Hooke discerned in the smallest organisms he examined convinced him of God's ingenuity, and spawned doubts about spontaneous generation. And the tiny could be just as impressive as the big, the flea, mite and gnat meriting comparison to the horse, elephant, and lion. One of the most commonly used terms in biology — "cell" — was actually coined by Hooke. The magnified chambers he saw in cork and other specimens reminded him of monastic living quarters. When it came to wriggling specimens, he applied the same ingenuity he had used in improving light sources to getting his tiny subjects to lie still. He had particular trouble with the ant:

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Drunken ant from Micrographia by Robert Hooke

This was a creature, more troublesom to be drawn, then any of the rest, for I could not, for a good while, think of a way to make it suffer its body to ly quiet in a natural posture; but whil'st it was alive, if its feet were fetter'd in Wax or Glew, it would so twist and wind its body, that I could not any wayes get a good view of it; and if I killed it, its body was so little, that I did often spoile the shape of it, before I could throughly view it . . .

He soon found a solution: putting the ant in brandy to make it "dead drunk." Hooke enjoyed the ant's drunken cooperation for about an hour, then it "suddenly reviv'd and ran away."

He might not have had the best sense of humor about himself, but even the royalist Hooke was willing to make the occasional witty pun aimed at people in high places. The lowly louse, he quipped, was "so proud and aspiring withal, that it fears not to trample on the best, and affects nothing so much as a Crown."

Hooke's opportunities to see and write about so many natural phenomena came at a price. Over the years, the pressure that the Royal Society placed on him was alarming. In a three-week period in October 1663, for instance, his assignments from the Royal Society included using a concave glass to project an image in a lighted room, making a device for measuring the force of gunpowder, preparing a paper on what must be recorded for the history of weather, preparing a thermometer made of tin, preparing a thermometer made of glass, preparing a device for taking soundings at sea for demonstration to King Charles II, making a device that shows changes in atmospheric humidity from the beard of a wild oat, displaying microscopic observations of both a fly and a bit of moss growing on a brick, labeling every single object in the society's curiosity collection at Gresham College with its name and provenance, manufacturing an artificial eye, removing and reattaching a piece of dog's skin to see whether it would grow again, and grafting feathers onto a rooster's comb. All of this in just three weeks.

Even after Hooke took on substantial duties as a city surveyor, the Royal Society remained just as demanding of his time, even though it was lax in compensating him. The fault lay partially with Hooke; throughout his life, he wanted one of his fingers in every pie in his vicinity. He loathed Henry Oldenburg, who preceded him as Secretary for the Royal Society, for lax minute-taking that deprived Hooke of proper credit for some of his inventions. Yet when Hooke took over the responsibility, his own note-taking suffered serious lapses. Hooke's relationship with the larger society was stormy, and more than once he vowed to leave, though he never did.

Hooke's paid position put him in the uncomfortable situation of acting as a servant to other society fellows. He probably needed (or at least felt he needed) the money, but may have resented taking orders. And despite delegating tasks that required a near-Herculean effort on his part, the society voted to eschew any responsibility for any controversial thing he wrote. In other words, he could carry out experiments for the society, but if he wanted to philosophize on the results, he was on his own. The society's limited-liability stance may have been one more thing that grated. So, perhaps, was the relative luxury of his fellows' country estates, where they could retreat during heat waves or epidemics. No matter how bad things got in London, Hooke had nowhere else to go.

It may have been in response to the constant pressure from the society (and himself) that the experimentalist Hooke performed plenty of experiments on his own body. Many of his adventures in self-experimentation were dangerous; almost all of them were pretty disgusting. At various times, he medicated himself with botanical purgatives, botanical emetics, mercury, steel filings, tobacco, absinthe, and mineral water so foul that he found ammonium chloride preferable to it. Hooke obsessed over getting a good night's sleep and clearing out his lethargic digestive system; he often found his home remedies violently effective. He authored a recipe for turning urine into phosphorus salts, including an intermediate step of letting the effluvia sit "till it putrify and breed Worms."

Some of Hooke's self-experimentation happened for an audience. At one of its meetings, the Royal Society demonstrated the effects of a vacuum pump that removed the air from an enclosed chamber for a cousin of the king. Hooke later recounted, writing about himself in the third person, "A man thrusting his arm upon exhaustion of the air had his flesh immediately swelled, so as the blood was neere breaking the vains, & unsufferable." Royal Society fellows scrutinizing his arm immediately after he pulled it out found it "speckled."

Hooke's self-experimentation wasn't that unusual for the time, but over the years, his self-medication took its toll. Full of energy when young, he became in later years, in the words of one acquaintance, "nothing but Skin and Bone, with a meagre Aspect." His situation wasn't helped by a sheer terror of outliving his estate. Despite owning a treasure chest stuffed with money and precious stones, he began living like a miser. According to some rumors, he almost starved his live-in maidservant along with himself. In the words of historian Lisa Jardine, "Some men mellow in later life; Hooke was clearly not one of them."

Hooke's passion for developing the best observational instruments, as well as his possessiveness about his ideas as a natural philosopher brought him into frequent disputes. One of the disagreements was with Christiaan Huygens over who deserved credit for inventing the balance-spring watch. Hooke's long-time nemesis Oldenburg also played a role in stirring up a controversy between Hooke and a French virtuoso, Adrien Auzout, who wanted to know more about grinding microscope lenses. Oldenburg translated correspondence between Hooke and Auzout. Oldenburg's translations both omitted niceties and added an edge each savant's criticisms of the other, letter after letter. The result was that Hooke emerged with a worse reputation on the Continent than he really deserved.

Hooke also butted heads with Isaac Newton. About the same time he built a telescope that rivaled any of Hooke's inventions, Newton submitted a paper on optics, which was given to Hooke for review. Hooke, perhaps smoldering over his own upstaged scientific instruments, poured scorn on Newton's paper, writing a scathing review in just hours. Newton was so humiliated that he refused to try to publish the paper again until after Hooke's death. Beyond likely irritation over the telescope, Hooke differed with Newton on the nature of light and color. While Newton argued that colors combined to make white light, Hooke was sure that colors resulted from distortions of white light. The savants eventually shook hands, and it was in a conciliatory letter to Hooke that Newton wrote one of the most famous passages in science: "If I have seen further it is by standing on ye sholders of Giants." The statement may have inspired generations of scientific collaborators, but the Newton-Hooke truce didn't last nearly so long. The two quarreled again when Hooke claimed to have inspired Newton's theory of the inverse square law of celestial motion. In fact, the old man was not imagining; he had made impressive intuitive leaps, and he wrote Newton to discuss the hypothesis, but admitted it would take Newton's far superior mathematical abilities to prove the concept (and it did). For his own part, Hooke remembered his own intuitive leap, but apparently forgot Newton's superior math skills.

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Coffeehouse sign photographed by David Brown (some rights reserved)

In many ways, Hooke and Newton clashed because of their similarities; both men had endured hardships growing up, both took themselves seriously, and both guarded their discoveries jealously. One could argue that Newton was in many ways even pricklier than Hooke. However, Hooke divided his time and talent among many different tasks, running after each shiny new endeavor like a magpie, and gossiping about his exploits in coffeehouses. (Garraway's was one of his favorites, and the meeting place of a Royal Society-offshoot "philosophical club" he started in the 1670s.) Newton meanwhile possessed the single-minded determination — and financial resources — to isolate himself and follow a problem to the end. Newton was like Leeuwenhoek in this respect; he stuck with an endeavor for years while Hooke's interest waned. A contemporary Royal Society member, Thomas Molyneux, described Hooke as "hated and despised by most of the Royal Society, pretending to have [made] all other inventions, when once discovered by their authors to the world." By the time Hooke had his final dispute with Newton, the aging savant had claimed credit for someone else's idea or invention once too often. Even Hooke's coffeehouse buddies didn't quite believe him.

In January 2006, a remarkable find vindicated at least one of Hooke's priority claims. An auction-house representative realized he was examining a 320-year-old volume of Hooke's notes, which included detailed accounts of Hooke's work on balance-spring watches. Unsurprisingly, the notes also revealed a few more of Hooke's spats, even one with his patron Robert Boyle.

Not every remnant of the cranky old man's life survived so well. After Hooke died, Newton quickly became president of the Royal Society of London, and Hooke's death presented his nemesis with an ironic problem: While Hooke had resided at Gresham College, the Royal Society had been able to use the college's facilities. Once Hooke died, college trustees told the society to leave. It fell to Newton and fellow members to move the Royal Society to new headquarters, and among the many items to be relocated was Robert Hooke's portrait. During the move that Newton oversaw, the portrait simply disappeared.

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