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After receiving Leeuwenhoek’s letter of October 9, the Royal Society could no longer ignore Leeuwenhoek’s claim to have discovered a previously invisible world of microscopic creatures. The letter was translated and read to the fellows over the course of three meetings of the society in early 1677. Oldenburg was instructed by the society to inquire about the methods used by Leeuwenhoek in observing these little animals, as well as his methods for calculating their numbers. The Royal Society fellows not only doubted the existence of these minute creatures but felt that, even if there were a whole invisible world of life forms, Leeuwenhoek must surely be exaggerating the numbers of tiny organisms he had seen. They requested that he explain his calculations.
Leeuwenhoek replied that he had used a grain of sand as a benchmark (he might even have put one into the tube he was observing). He could see that there were about one thousand creatures in the volume of water about the size of a sand grain. He calculated that, since one thousand grains could fit in a drop of water, there must be about one million little creatures in that drop. Leeuwenhoek showed how this method was similar to that used in more familiar cases, such as estimating the size of a flock of sheep by figuring that the animals are running alongside one another, so that the flock has a breadth of a certain number of sheep, and multiplying this number by a length determined in a similar manner. Later, when reviewing his method, he calculated that there could be over eight million animalcules in one drop of water. This was staggering—imagine how many tiny animals there must be in a bucketful of water, or a well, or a lake! As Leeuwenhoek himself acknowledged, “This exceeds belief.”
When the letter from Leeuwenhoek was reprinted in the Transactions, the Royal Society fellows took the precaution of adding a prefatory note: “This Phaenomenon, and some of the following ones seeming to be very extraordinary, the Author hath been desired to acquaint us with his method of observing, that others may confirm such Observations as these.” The Royal Society would withhold its seal of approval until others were able to replicate Leeuwenhoek’s observations. But in order to do this, they would need to know how he made those observations.
Leeuwenhoek, however, refused “to acquaint” the Royal Society “with his method of observing.” He would tell the society neither the exact techniques he had used for making his observations nor the technical specifications of his microscopes. The fellows were infuriated with Leeuwenhoek for withholding this information from them. Who was this upstart, they must have thought, to refuse them instructions for replicating his wildly unlikely claims?
Like the artists of the St. Luke’s Guild, like Torrentius, like Vermeer, Leeuwenhoek refused to divulge his secret techniques. This was not unusual at the time—even Evangelista Torricelli, when he became a master of polishing lenses in the early 1640s, refused to reveal his polishing methods—but Leeuwenhoek was caught in a pendulum swing going the other way. At that very moment the Royal Society was trying to assert openness, publicity, and repeatability as hallmarks of science. In part this was to set the “new science” apart from natural magic and alchemy, whose adherents used secrecy to elevate the mysteriousness of their endeavors and to restrict knowledge to a circle of initiated adepts. It is a mistake to view alchemy the way most of us do, as involving wizard-like figures bent over bubbling cauldrons (although there was some of that). Alchemists were really the first chemists, engaging in experiments and basing their arcane search for the “philosophers stone” that could turn any substance into gold on known chemical principles. Yet they used the “hiding of names,” or the technique of using cover names for ingredients or results, in cases where they deemed that a “veil of secrecy” was necessary to screen out readers unworthy or potentially abusive of the secret knowledge. This led to the reputation of alchemy as a mysterious—and even mystical—undertaking.
Already in Leeuwenhoek’s time, the Royal Society deemed such obfuscation no longer appropriate for science. It had begun to stress the importance of replication and publicity—natural philosophers were now expected to inform the scientific community not only of results but also of the methods used to achieve the outcomes, allowing colleagues to repeat experiments and observations. Eventually, the alchemists were done in by this requirement, but it took time; in Leeuwenhoek’s day there were still fellows of the Royal Society who dabbled in alchemy. Robert Boyle, for example, attempted to learn alchemy’s secrets and methods. He went so far as to request that he be inducted into a secret society of adepts, only to learn that their castle was destroyed by a bomb right before the scheduled ceremony. He even wrote alchemical works and believed in the possibility of a philosopher’s stone, hoping that it could not only turn base metals into gold but also attract “angels.” (The Royal Society may not have realized the extent of Boyle’s commitment to alchemy, because he hid it in his writings by the use of codes.)
Even in the eighteenth century practitioners of the alchemic arts could still be found among the fellows of the Royal Society. One of them, James Price, would claim in 1782 to have turned mercury into silver using a white powder and into gold using a red one. But by that time such claims were not to be tolerated. The president of the society, Sir Joseph Banks, denounced his work as “charlatanism” and demanded that he repeat the experiment in front of other fellows. In July 1783 Price invited fellows to his home for a demonstration, but on the appointed day he committed suicide by drinking poison—whether to avoid admitting he had lied, or to keep from revealing secrets to the uninitiated, no one ever learned.
Leeuwenhoek’s desire to retain his secrets particularly rankled the Royal Society leaders. At first he teased them, not stating outright that he refused to reveal his secrets, but answering Oldenburg’s request for explanation by saying,
At present I use quite a different method of observation, which is as reliable as can be invented (barring improvements) and if I should be inclined to make this method known, I do not doubt that you and all the Gentlemen Amateurs would esteem my instruments and method of observation.
But, as the Royal Society fellows soon realized, Leeuwenhoek would not be so inclined. “My method for seeing the very smallest animalcule,” he would later firmly insist, “I do not impart to others.”
He recognized that, because of this secrecy, it would be more challenging to convince the society of the truth of his observations. “The fault is mine,” he admitted to Oldenburg, “since … I have the intention to keep the method I use secret from everybody.” He did disclose that he was using a thin glass capillary tube in order to view the animalcules, but he would say nothing else about the type of microscope or lenses that he was using, the light source, or any other information that would be useful to someone trying to see for himself what Leeuwenhoek had observed. However, he invited fellows of the Royal Society to travel to Delft, where he would be happy to show them himself. Given that the Third Anglo-Dutch War had ended the year before, in 1674, it is a little surprising that the Royal Society did not send a delegation immediately to Delft to confirm the observation of something that was even more striking than Galileo’s discovery of the satellites of Jupiter or the craters and mountains on Earth’s moon.
Since the Royal Society would not come to Delft, Leeuwenhoek brought his observations to London—not by making the journey there himself, but by sending legal affidavits signed by witnesses who had looked through Leeuwenhoek’s microscopes. One was signed by Aldert Hodenpijl, a Delft innkeeper; one was signed by Alexander Petrie, the pastor of the English congregation in Delft; one was attested by Benedictus Haan and M. Henricus Cordes, both Lutheran pastors, one by the Delft notary Jan Boogert, along with Robert Poitevin, a doctor of medicine at the University of Montpellier, and W. V. Burch, a notary who was also an advocate in the court of Holland; and one by Robert Gordon, a medical student.
As befits religious leaders, the affidavit of Haan and Cordes starts off reminding the Royal Society fellows of the role of scientific inquiry in honoring and praising God, “the Creat
or of everything.” Alluding to Leeuwenhoek’s confidence in his abilities, the men note, “Our Antoni Lewenhoek does not stand in the rear of those who have displayed an almost incomparable eagerness in unveiling the secrets of nature with the greatest accuracy and exactitude.” To find anyone capable of seeing more with a microscope than Leeuwenhoek would be like “claim[ing] more light from the sun.” Getting, finally, to the point:
Well, as eye-witnesses we affirm that we saw at least 200 living creatures in this 50th part of water [in a hollow tube as thick as a horse’s hair]; little animals which moved and swam in the water, so that we could distinctly see that they were indeed animals and by no means something else.
The medical student, having viewed the little animals with Leeuwenhoek in early June, stated that he saw as many as twenty thousand of the creatures in a quantity of “pepper-water not exceeding the size of a grain of millet.” In August, Hodenpijl, the innkeeper, claimed to see “above thirty thousand Living Creatures.” Boogert, the notary of Vermeer’s mother-in-law, and his two co-observers, attested that they saw each of ninety parts of water in a little tube contained more than five hundred little animals—forty-five thousand creatures in all. When the tube was emptied, they saw that the quantity of water “did not exceed the size of a grain of millet.” At the end of August, Leeuwenhoek invited the Englishman Alexander Petrie to his house. Petrie noted in his attestation that when Leeuwenhoek added vinegar to the water, the animals stopped moving, “being killed by the vinegar.”
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While Leeuwenhoek was compiling his affidavits, the Royal Society was working on replicating his observations. On April 5, 1677, the society requested that one of its fellows, Nehemiah Grew, try to see what Leeuwenhoek had reported observing. Grew was famed for his microscopical study of plants, but his work with a microscope was drawing to a close; by December 1677 he would cease his microscopical studies. He may already, by April, have lost interest in the device. The Royal Society fellows waited in vain to hear something back from Grew. Finally, six months later, a year after Leeuwenhoek’s letter, they asked Hooke to make a single-lens microscope like Leeuwenhoek’s and attempt to see the animalcules with it.
Hooke, too, by this time, had abandoned his microscopical investigations. He was involved in experiments on the blood and lungs of living animals, which aimed to determine the unknown relation between respiration, heartbeat, and circulation of the blood. He developed new circular and inclining pendulums that could keep time as accurately as the longer, perpendicular ones, in his continuing quest to develop a watch that could keep precise time at sea, thus aiding captains in determining longitude. He worked on improving astronomical instruments and began making his own astronomical observations from his rooms at Gresham College. He presented a series of lectures on earthquakes. He had also become busy with his duties as a city surveyor, and had begun work as an architect, designing buildings—especially churches—as part of the effort to rebuild London after the Great Fire of 1666. Hooke was so busy with his various pursuits that he was neglecting his duties as curator of experiments for the Royal Society, so much so that in November of 1670 the society’s council resolved to censure him for his neglect of office (this resolution was never carried out, however). In the following years Hooke continued his own experiments on light, arguing with Newton over the nature of this phenomenon, whether it was composed of waves—as Hooke believed—or particles—as Newton thought. (No one realized that light comprised both waves and particles until the twentieth century.)
But when the Royal Society charged Hooke with replicating Leeuwenhoek’s observations, Hooke jumped to the task. Quite possibly Hooke saw Leeuwenhoek’s discovery as a challenge, something that he, the author of the Micrographia, should be able to confirm by being the second person to see living microscopic animals.
Taking Leeuwenhoek’s hint about using very small glass tubes, on November 1, 1677, Hooke showed the society “a great many exceedingly small and thin pipes of glass of various sizes some ten times as big as the hair of a man’s head others ten times less.” Hooke rather disingenuously claimed that he had thought of using these tiny capillary tubes himself, when that was the one piece of information actually supplied by Leeuwenhoek in his March 23 letter.
Yet using this contrivance to examine water he obtained from a pump, Hooke was unable to see any tiny creatures (though they surely existed in abundance, given that London pump water came directly from the Thames, into which human and animal waste was dumped in profusion). Hooke proposed to try an infusion of pepper water. At the following week’s meeting, he reported that even with stronger microscopes, and water in which pepper had been steeped for two days, no little creatures could be seen, though he did see the dust of the ground-up peppercorn. Apparently he was busy as well with other trials that week, next reporting on experiments to replicate the fine “French leather” that was “impervious to water.” Finally, at the meeting of November 15, Hooke announced that he had been successful.
This time he had steeped whole black peppercorns in rainwater for nine or ten days. In this water he had seen “great numbers of exceedingly small animals swimming to and fro.… [T]hey were near an hundred thousand times less than a mite.” Hooke demonstrated his observations to the fellows present at the meeting. As the meeting minutes record, “[The little animals] were observed to have all manner of motions to and fro in the water and by all who saw them they were verily believed to be animals and that there could be no fallacy in the appearance.” The record of the meeting continues, “They were seen by Mr Henshaw, Sir Christopher Wren, Sir John Hoskyns, Sir Jonas Moore, Dr Mapletoft, Mr Hill, Dr Croune, Dr Grew, Mr Aubrey, and divers others so that there was no longer any doubt of Mr Leewenhoeck’s discovery.”
Now that these distinguished men of the Royal Society had seen with their own eyes, “there was no longer any doubt,” as the meeting minutes indicate, that Leeuwenhoek had discovered microscopic life. Hooke was even commanded to show the little creatures to Charles II; His Majesty was “very well pleased with the Observation,” Hooke reported to Leeuwenhoek. As a snide comment on Leeuwenhoek’s furtiveness, Hooke soon published a short tract in which he openly described a variety of methods that others could use for making their own observations of microscopic life. Snideness aside, Hooke’s observations cleared the way for acceptance of Leeuwenhoek’s discovery. “Seeing is believing,” as the philosopher John Locke said of the Royal Society’s replication of Leeuwenhoek’s observations. Previously, “We had such stories written [to] us from Holland and laughed at them.” Even years later many people would doubt Leeuwenhoek’s findings. He knew this, and was resigned to it. “I’m well aware that these my writings will not be accepted by some, as they judge it to be impossible to make such discoveries,” he confessed. “Among the ignorant, they’re still saying about me that I’m a conjuror, and that I show people what don’t exist.” But Leeuwenhoek was not a magician, conjuring up illusions in a puff of smoke. He had seen, for the first time, the invisible living world.
*1 The Rembrandt portrait had been thought to be a false attribution until it was cleaned in 2008; it was lent to the Rembrandthuis in Amsterdam until the end of 2015 by its owner, the Royal Museum of Fine Arts, Antwerp. The portrait of Henricus Swalmius is owned by the Detroit Institute of Arts.
*2 Opinion is divided on whether Newton actually did perform this experiment; it may have been what philosophers call a “thought experiment,” imagining what would happen if he stuck a needle into his eye.
*3 These are believed to have been Rotifers.
*4 These are believed to have been Ciliates.
*5 These are thought to have been Euglena viridis, a flagellate whose discovery was originally attributed to John Harris in 1696.
*6 Today one can see the labels Leeuwenhoek wrote for specimens at the Royal Society at the Royal Society Library, so it is easy to imagine what these infusion labels would have looked like.
PART 10
Generations
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IN DECEMBER OF 1675, Johannes Vermeer died quite suddenly. He had, according to his widow, Catharina Bolnes, “fallen into a frenzy” of some kind, and in less than thirty-six hours had “gone from being healthy to being dead.” Only forty-three years old, he may have had a stroke or a heart attack, perhaps brought on by the pressure of trying to pay off his debts and feed his ten children still at home, who ranged from less than two years old to eighteen. (Their eldest child, Maria, had recently married and left home.) Things had been tough for some years, ever since the war with France and the rampjaar of 1672. Vermeer’s production of his own works had slowed to a crawl, and his business dealing in pictures had fallen off, until he was unable to sell any paintings at all. Over the summer he had taken on a huge debt—one thousand guilders ($13,568 today)—from the Amsterdam merchant Jacob Rombouts, using his mother-in-law’s capital property as collateral for the loan, instead of holding on to it for her as he had promised.
Catharina had gone to the funeral at the Oude Kerk, where Vermeer was buried in the family plot Maria Thins had purchased in 1661, a plot that already contained three of their children, who had died in 1667, 1669, and 1673. Catharina had watched as the grave site of the baby they had buried in June of 1673 was dug up, her husband placed into the frozen ground, the baby’s little coffin lowered on top of his father’s. She was left in charge of her remaining family, but had no idea how she could support them. As her own mother would attest before a court, Catharina “had never concerned herself further or otherwise than with her housekeeping and her children.” Now what would happen to them?
Eye of the Beholder: Johannes Vermeer, Antoni van Leeuwenhoek, and the Reinvention of Seeing Page 30
