Antoni van Leeuwenhoek and the Royal Society during the Dutch

Antoni van Leeuwenhoek and the Royal Society during the Dutch Golden Age
Tatiana D. Waterman
Phillips Exeter Academy, Exeter, NH
NEH Seminar 2007; The Dutch Republic and Britain:
The Making of Modern Society and a European World Economy
Antoni Leeuwenhoek (1632-1723), the founder of biology, has been derided by twentieth-century biographers who have written carelessly, describing his station in life dismissively
as: cloth merchant, draper merchant’s servant, minor city employee… These biographies reflect
ignorance of the historical period in which Leeuwenhoek lived and of which he was a product.
In his unsurpassed biography of Leeuwenhoek, Clifford Dobell wrote,
Outside of Holland, little has been written about him, which is not almost comically inaccurate. The biographical dictionaries are stuffed with ridiculous statements, and most historians of biology have hitherto been content to reprint their
mistakes. … To appreciate Leeuwenhoek properly, it is necessary to know not only
the particular history of many sciences but also the general history of his own times;
to see him in his true perspective, it is even necessary to understand the relations of
Holland and England in his day, and the peculiar circumstances which led to the
founding of the Royal Society and to his connections with that learned assembly.
(pp. 11-12)
Indeed, Leeuwenhoek first made his money in the textile business and then he devoted
himself to scientific research; this was not unusual for his era. Many of his contemporary scientists were also connected to commerce or trade. Christopher Wren saw the market and profit potential for the images seen under the microscope. Edmund Halley used his talents in mathematics and astronomy to benefit commercial navigation. England offered a substantial financial prize
for a method of calculating longitude. Cartography and surveying were collaborative projects
between individuals and nations: France and England—historic enemies—joined forces with the
Dutch to support and improve cartography; the famous Blau maps were the mainstay of all seafaring nations.
In the seventeenth and eighteenth centuries, science and technology were linked with
trade and profit. New technologies and advances in existing technologies were driven by the
needs of manufacturing and the demands of the growing markets. Antoni Leeuwenhoek was a
typical middle-class citizen of the Dutch Republic; his involvement with science, fostered by The
2
Royal Society, a non-academic institution of learning, exemplifies the scientific process of the
era.
The Instructor of Europe
“In physics, the Dutch Enlightenment was the intermediary between Britain and
the Continent. But in microscopical science and medicine, the Dutch Enlightenment may fairly be described as the instructor of Europe, including Britain.”
Jonathan Israel (p.1043)
When Leeuwenhoek was grinding his lenses and looking at nature through his microscope, it was a great time to be a citizen of the Dutch Republic. Vermeer, Rubens, and Rembrandt were creating their masterpieces in Delft, Amsterdam, and Leiden. Christian Huygens
and Willibrod Snell were discovering the secrets of the behavior of light, while Jan van der Heyden’s street lamps were illuminating the night. Quietly, Baruch Spinoza was putting the stamp
of his own intellect on the legacy of ideas that Rene Descartes had left behind, rejecting the Bible
as a textbook of nature’s laws. Huygens, too, questioned and challenged many of Descartes' details, even though he was positively influenced by Descartes’ central idea that the natural world
can be explained by mathematical modeling. Descartes, a religious refugee from France, was an
honorary Dutchman and a celebrity in Europe. Christian’s father, Constantijn Huygens, the Minister of War in the service of the Prince of Orange, was devoted to science as well, and had spent
many evenings in the company of Descartes.
The university in Leiden boasted a faculty line-up of the 'who-is-who' in Europe. Under
the leadership of Herman Boerhaave and Willem Jacob ’s Gravesande, Newton’s physics was
annotated, popularized, and spread in continental Europe. The curriculum innovations were
strikingly advanced: the Leiden professors not only used books and lecturing for teaching the
humanities, but also instruments and demonstrations for teaching the newest scientific ideas and
discoveries. The ‘force tables’ used in physics classrooms today were first designed for ’s Gravesande’s physics classes. Voltaire attended ’s Gravesande’s lectures when he was preparing his
handbook on Newton. Carl Linnaeus, the Swedish botanist, spent many years in the Netherlands
researching rare and exotic plants in Dutch collections. (His Systema Naturae was published in
Leiden.) Boerhaave’s medical textbooks were translated in many languages, including Turkish
and Japanese. 1
1
Not surprisingly: the Ottoman Empire was at its peak; also, the Dutch were the only Europeans allowed trade privileges by Japan. For more information, see Sharlyn Scott’s “The Dutch in Japan.”
3
With superb drainage engineering, the Dutch Republic (today’s Netherlands) had tamed
the raging of its rivers and seacoast, claimed new earth area from its marshes, and boasted the
best canal system in the world for transportation. By the mid-1600s, the Dutch Republic had become the nerve center of European commerce and global maritime trade. Taking advantage of
its strategic geographic position and deploying its profitable and efficient ships, it became the
major transporter of European staples from producers to consumers. In the sixteenth century,
Amsterdam had the first commodities and stock market—complete with financial derivatives—,
which worked so well that it became the model for our modern financial markets. The United
Dutch East Asia Company, the VOC (Vereenigde Oostindische Compagnie), the largest trading
and shipping company in the world was at its peak. Its ships sailing all over the globe.
Governed by a novel system—with state governors rather than a king to lead them—the
citizens of the Dutch Republic enjoyed a “flattened” social ranking, with a prosperous middle
class to which anyone could belong. If one got along with his neighbors, was a productive
worker, and contributed to the peace and prosperity of the country, one was given the opportunity of a good life. Women were on equal footing with men in terms of financial responsibilities,
social freedoms, and rights.
Undeniably, there were problems of exploitation and greed in the job market, but it was
not like the rest of continental Europe where royals and aristocrats did not plan or invest wisely
and did not care about the serfs. The Dutch were rich, powerful, and smart enough to reinvest
their profits. While in other parts of Europe property and life were precariously dependent on
one’s religious affiliation, the thinkers of the Dutch Republic were allowed to examine the role
of the clergy in religion and to question the place of clergy in the country’s social structure without fear for their lives. Organized religion was put in the service of the Republic and its citizens.
These social norms did not all develop bloodlessly or without strife, but by the second half of the
seventeenth century the Dutch Republic had given the world a new paradigm for a tolerant society. The model worked, and with their Protestant work ethic, the Dutch were content, taking
care of business with level heads and open minds, and prospering. Not since the golden age of
the ancient Greeks had the western world seen such dynamism of ideas in government, in the
economy, and in intellectual pursuits.
The Royal Society—Clearinghouse of Knowledge and Research
Across the North Sea, Britain was an emerging maritime power, vying with the Dutch for
trade and commerce, and copying many of the Dutch ways and methods. Britain had gone
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through tough political times, surviving a civil war which along with the Glorious Revolution
limited the absolute power of the king. While in other European countries serfs were still working for an upper class that had given little thought to wise investing or use of resources, the British were ushering in the modern world with a slowly but steadily emerging middle class. A class
of farmers, traders, and shopkeepers was starting to prosper and entrench itself with a web of
commerce and finance, bringing the country out of the medieval mode of economy. Astutely, the
British parliament put the navy in the service of the national economy.
Safely beyond the reach of the Pope and the Inquisition, Christopher Wren, Robert
Hooke, and Edmund Halley were discussing the trajectories of comets in London coffeehouses.
These three were among the twelve founding members of the new Royal Society; in 1660, ten
years later, the Royal Society’s membership had grown to 230 men. Hooke was the experimenter and jack-of-all-trades for the Society; Wren, better known to us as an architect, was an
astronomy professor at Oxford. (Wren and Hooke directed the rebuilding of London after the
1666 fire.) Halley, the son of a middle-class soap manufacturer, was the astronomer known for
“his” comet. Halley’s family background may have been humble and “smelly,”2 but his father
knew how to make money; he also understood what money can and should buy. Recognizing his
son’s mathematical talent, Halley’s father spared no expense: tuition for St. Paul’s and Oxford,
and the bankrolling of a two-year sea voyage for his son. Keenly interested in navigation improvement, the East India Company provided Halley free passage on a merchant ship, the Unity.
While the continental astronomers with their new instruments were trying to make minute corrections to Tycho Brahe’s naked-eye observations, Halley used his expedition to advance commercial interests; he decided to map the southern skies. After some research in nautical weather
logs, he realized that the island of St. Helena was the best place for observations. On the Unity,
he took with him a 24-foot refracting telescope, a two-foot quadrant, a six-inch sextant fitted
with a micrometer scale, and an assistant. (His father gave Halley an allowance of 300 pounds
per year. The king paid the astronomer Royal in Greenwich 100 pounds per year.) In two years,
Halley became the Tycho Brahe of the South. His map of the southern sky constellations was of
invaluable help to navigators when they crossed south of the latitude of Cape Verde. Before
Halley’s map, under uncharted stars, in order to know where they were, ships had to sail close to
the coast of Africa for landscape clues, worrying about treacherous skerries.3 Halley’s work
2
3
Extracting fat from animal carcasses to be used as a base ingredient for soap produces an incredible stench
Skerry is a Scots word, meaning ‘a rocky outcrop close enough to the sea surface to cause damage to ships.’
5
saved lives and increased profits in shipping significantly. This feat brought him recognition in
London and membership in the Royal Society at the age of 21.
The Royal Society of London for Improving Natural Knowledge is the oldest public institution devoted to the pursuit of scientific research; it aspired to combine the role of research institute with that of a clearinghouse and repository of new knowledge. Its goals were, and still are,
to publish new scientific knowledge and promote its discussion, while also encouraging research.
Noble as this may sound, its founding members were practical men, part of the financial fabric
and trade web of the country. They saw and understood the connection between natural knowledge and financial rewards. They also saw the difference and the disconnection between formal
university curricula and everyday business. A century after its publication, the venerable universities of Oxford and Cambridge had not introduced Copernicus’ model of the solar system into
their curricula; Galileo’s books, owned and discussed by the Royal Society’s members, had not
made it to university library shelves. Yet, in London, exotic knowledge was pouring in from
faraway places, as the ships of the British East India Company (E.I.C.) were bringing back flora,
fauna, tales about natives, and observations about weather, climate, and geology from all the
known parts of the globe. Knowledge was also generated at home; in Cambridge, Newton had
just invented calculus and was expanding Galileo’s legacy on the motion of bodies and gravity—
but not many of his university peers had heard about it yet.4 This new knowledge was welcomed
and published by the Royal Society—even though in some continental European countries one
could be burned at the stake for such activities. Such freedom of scientific pursuits was also encouraged and enjoyed by the Dutch.
Instrumental in establishing the Royal Society's scientific conduct was its first secretary,
and one of its founding members, Henry Oldenburg (c. 1619-1677). He initiated the practice of
sending submitted manuscripts to experts who would judge their quality before publication, and
he oversaw the publication of the Philosophical Transactions of the Royal Society from its start
in 1665 until 1677. This was the beginning of both the modern scientific journal and the practice
of peer review. The Philosophical Transactions of the Royal Society continues to be published
today; it is the longest running scientific journal in the world. Oldenburg was born in Bremen,
Germany, the son of a professor at the Royal University of Dorpat. As a university student, he
trained in theology, an education not unusual for his time; it was a preferred education with
4
Newton was discovered by Halley, who coaxed both him and the Royal Society to publish his Principia; Halley
paid for the printing expenses.
6
Latin, philosophy, and possibly some mathematics—there were no science degrees at that time.
When Oldenburg was sent to England by the Council of Bremen to negotiate with Cromwell in
1653, he settled in London, married an English woman, and became a naturalized citizen of England. Because Oldenburg was a foreigner in England, it was suspected that his extensive foreign
correspondence was political rather than scientific. He used the anagram Grubendol to reduce
the volume of mail coming to his name, and he also used his trusted in-laws to receive and send
his Royal Society letters. In the hysteria and panic that ensued when Admiral Michiel de Ruyter
led the Dutch fleet on his famous raid up the Medway, Oldenburg was imprisoned briefly5 in the
Tower of London, in 1667, even though he was a life-long friend of Robert Boyle, who defended
Oldenburg's innocence.
Training in Amsterdam
Seventeenth century image making was propaganda, art, craft, science, and, in Leeuwenhoek’s home country, it was also big business. According to experts, Vermeer used a single-lens
camera obscura to get ideas for his compositions; this act does not detract from his genius. His
choice of point of view, viewing angles, and his ingenious, purposeful placing of dots of white
paint on the canvas which produced dazzling results of shimmering light, were his gifted technique and his creation alone—a feast for the eyes and brain. Rembrandt became a rebel, using
light to show the truth, painting his subjects as they truly were rather than fabricate false beauty.
Vermeer, Rubens, Rembrandt and their colleagues were products of their scientific and technological times; they were also products of their financial times. The Dutch had the money to
commission and to buy numerous paintings. The artists who flocked to the Dutch Republic, either as religious or as economic refugees, created great art in ample supply. This combination of
ample supply and numerous buyers also produced the right conditions for specialization.
As religious refugees from today’s Belgium flocked to the towns of the Dutch Republic,
the textile industry was booming. The new workers were received eagerly because they brought
with them know-how and techniques for making first-rate draperies cloth. Drapery—a light
cloth, made with long-staple wool—enjoyed excellent marketability in warm climate countries.
It was one of the most profitable goods manufactured and traded by the Dutch in the sixteenth
century.6 The openness of Dutch society and the free thinking attitude of its people made the
5
6
He was soon released; ten years later he died peacefully from illness at his home in Pall Mall.
For more information on draperies, see Jan deVries, The Economy of Europe in an Age of Crisis.
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Dutch Republic a haven for refugees who brought their talents to their new homeland, supplying
the economy with dynamism rivaled only by the English.
Into this thriving commercial and scientific world, Antoni Leeuwenhoek was born in
Delft in 1632. His mother, Grietje van den Berch, following the early death of his father in 1638,
sent young Antoni to school in the village of Warmond. When he was a little older, she sent him
to Benthuizen to live with his uncle Cornelis Jacobsz van den Berch. In Benthuizen, his uncle
was the sheriff and bailiff of the village. The plan was for young Antoni to study law. It soon
became clear that Antoni's talents tended to be more practical, and that he would not make a
good lawyer. So, his mother sent him to Amsterdam to learn a trade when he was sixteen. In
1648, the year in which Antoni became an apprentice, the Treaties of Westphalia and of Munster
were signed. It was the moment when “Holland had taken her place in the very front rank of the
civilized world, as the home of letters, science and art, and was undoubtedly the most learned
state in Europe.”7
The van der Berch clan, Antoni’s mother's grandfather, her uncle, and her brother-in-law,
worked in the cloth trade. A friend of these relatives, the well-connected wool cloth merchant
Pieter Maurits Douchy, welcomed Antoni and placed him for apprenticeship with William Davidson, a Scottish merchant of draperies based in Amsterdam.
Born in Dundee (Scotland), and married to Dutch women three times, Davidson "brought
to his third marriage, in 1660, a fortune of 230,000 florins, while his wife, Elisabeth van Clenck,
daughter of a family of high standing, brought with her a dowry of 24,000 florins plus goods and
jewels valued at 4,000 florins.” 8 Davidson was a distinguished wholesale merchant with extensive connections in the Baltic ports of trade. He was the King of England's Agent in the Netherlands. When Mary Stuart, widow of Prince William II of Orange, came to Amsterdam in 1660,
she stayed at Davidson’s home. The burgomaster Cornelis deGraeff wrote excitedly about meeting the Queen there. 9
Leeuwenhoek’s extended family behavior was typical of the middle class of the era.10
They desired to educate and train their young, and they either had the means or scraped together
to pay tuition and apprenticeship money. Young Antoni was motivated to make something of
himself, and took advantage of his schooling and apprenticeship. Additionally, a network of re7
Edmundson, G., History of Holland, (1922) Cambridge. Quoted in Dobell, p. 24
Municipal Archives of Amsterdam. Notarial Archives, No. 1821, fol. 218. Notary: Albert Eggericx.
9
W. H. van Seters, Notes and Records of the Royal Society of London, Vol. 9, No. 1. (Oct., 1951), pp. 36-45.
10
For more on the middle class in the 17th –18th centuries, see Wrightson, Earthly Necessities, chapter 13.
8
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lations gave Antoni the character references that were essential for getting a good placement.
The confidence of his relatives was well rewarded as Antoni proved to be worthy of his family's
efforts.
Antoni, at the early age of sixteen, not only performed the functions of book and
cash keeper with an important draper, but also managed, within the space of six
weeks, owing to his assiduity, to attain the diploma of Certified Mastership in
Cloth-Making.11
He did his family proud. He might not have taken to scholarly learning, but he was motivated
and smart in other ways. Success in his case was achieved through gainful employment, rather
than with a diploma.
When the Second English war with the Dutch (1665-1667) broke out, Davidson's position
in Amsterdam became very uncomfortable, but he stayed until the middle of 1665 in spite of
suspicions that he was supporting a native Dutch spy and disclosing the movements of the Dutch
fleet to the English. When circumstances worsened, he had to move to Hamburg, and then to
Antwerp. In his absence, Davidson gave the young Leeuwenhoek power of attorney.
William Davidson authorizes Antoni Leeuwenhoek to hand over to Bookkeepers
the bills, signed by [Davidson], relative to amounts chargeable in banco (fixed currency) to [Davidson's] account with the Amsterdamse Wisselbank, and to inform the
latter accordingly. Moreover, to make up in anticipation for any possible deficiency
of the present warrant, Leeuwenhoek is herewith given power in general to take any
other steps which may be required for the settlement of this transaction. (Original is
in Dutch.) 12
Leeuwenhoek did not learn English while staying with Davidson, because Davidson
spoke with Antoni in Dutch. English traders in overseas ports customarily had full command of
the Dutch language; the Dutch had been premier traders for centuries, so their seventeenthcentury partners or competitors knew the language that was necessary for trade. Years later,
when Leeuwenhoek corresponded with the Royal Society, he wrote in Dutch; Henry Oldenburg,
who also spoke Dutch himself, translated the letters into English.
After six years in Amsterdam, in 1654, Leeuwenhoek returned to his hometown of Delft
where he married the daughter of a silk and draperies merchant and opened his own fabric shop.
Of Leeuwenhoek’s five children with his first wife, only one girl, Maria, survived to adulthood—a sad but typical statistic of life at that time. He also survived his second wife; only
Maria was there for him at the end of his life. His shop business earned the family a comfortable
11
12
Haaxman, P. J., Antony van Leeuwenhoek, de Ontdekker der Infusorien, Leiden (1875).
translated, W. H. van Seters Notes and Records of the Royal Society of London, Vol. 9, No. 1. (Oct., 1951), pp. 36-45.
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living. Leeuwenhoek was involved as a citizen in the usual way of the Republic, performing
civic duties for the town of Delft, “… as chamberlain to the sheriffs of Delft. He did his duty
diligently—sweeping the council room, arranging the decor, lighting the fire at the proper time
and also preserving any coal that might be left unconsumed.” (Dobell, p.31) He developed additional skills and earned the qualification of surveyor, a profession that required an understanding
of mathematics and facility with a telescope. By 1670, his good business sense, combined with
legendary Dutch frugality, helped him accumulate a fortune that afforded him the means to be
financially independent. At the age of almost forty, he could start devoting his time to his favorite research, his lenses.
Looking Far and Near
In the beginning of the seventeenth century, a new era of technology-based science
dawned. The new method of science established by Galileo demanded results and conclusions
derived from observations and measurements, not extrapolations from the Bible or abstract philosophical musings. Experimental data and reproducible results replaced meditational fancy.
Lenses to help extend the human eye’s ability, and timekeepers to quantify the measurement of
motion, were necessary and essential. It is no coincidence that England and Holland were the
leading places for budding scientists: the craftsmen of these two countries were among the best
in the world, and their shops were supported by thriving economies.
The telescope was patented in The Hague in October 1608 as a device that aided "seeing
faraway things as though nearby." Hans Lippershey, a German living in Holland, is credited with
the invention, but at least three other individuals were also designing telescopes and had them
almost ready within weeks or months of this patent date.
By 1609, Galileo had received a description of the telescope’s prototype, had made his
own superb copy, and had proved Copernicus correct by looking at the phases of Venus. His observation proved that Venus went around the sun, and astronomy started changing our world.
With the telescope, astronomers probed the heavens and collected extremely accurate data;
closer to home, mariners had an instrument to help them avoid disasters at sea. National observatories were funded lavishly in France and England for their potential help to navigation. At the
same time, merchants and speculators standing by the docks used the “spy” glass to earn trading
profits. The Medici family commissioned Galileo to make telescopes for them. Using the tele-
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scope, they could see merchant ships coming into harbor before their competitors; this enabled
the Medicis to fix cargo prices, knowing that a ship was approaching.
The invention of the microscope soon followed. In 1619, the Dutchman Cornelis Drebbel (1572-1633) was credited with the invention. His patent and proof of invention is a sketch he
made of the instrument in a letter he sent to King James, asking for a job in his court. By the
1660s, another Dutchman, Johannes Hudde (1628-1704) made improvements to the microscope
that made it suitable for use in serious research.
This was also the time when English and Dutch natural philosophers (the name by which
scientists were known) were enthusiastically exploring the laws of optics. Newton solved the
riddle of the rainbow with his classic experiment. Huygens, the Newton of Holland, established
the wave theory of light, which is standard optics learning in our modern textbooks. Huygens
was not just a physicist but also a great mathematician and astronomer. With excellent telescope
lenses, he observed the rings and moons of Saturn. His pendulum clock design (1656) had the
best precision known at the time. Christian Huygens and Baruch Spinoza collaborated frequently. Spinoza was very much interested in the experimental side of science13; he was an expert lens maker, better than Huygens.
In London, lenses were the high-tech toys that the rich were buying. Wren was the first
to appreciate the entertainment potential of the world seen through a microscope. In 1661, Wren
showed the microscope to King Charles II along with a few fine drawings of insects under the
microscope made by Hooke. The King, greatly entertained, asked the Royal Society to produce
more of these drawings of “microscopic” things. Wren, claiming to be busy, passed the assignment on to Hooke, convincing Hooke that there was a market for a book with such illustrations.
Three years later, Hooke published his Micrographia, and it was indeed a best seller; every respectable rich Londoner wanted one for his drawing room coffee table. It is still being printed.
It contains drawings of plants and insects, powerfully magnified, and it displays fascinating details. Samuel Pepys, the famous London diarist of the time, bought a copy of Hooke’s Micrographia on the spot. “…Thence to my bookseller's and at his binder's saw Hooke's book of the
Microscope, which is so pretty that I presently bespoke it … a most excellent piece, of which I
am very proud.” (20 January 1665). Pepys could not put the book down to go to sleep. He sat
13
Spinoza admired and explored the implications of Descartes' mathematical modeling ideas, but he was a staunch
follower of Galileo's model, which demands experimental proof for theories.
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up “…’till two o'clock [a.m.] in my chamber reading Mr. Hooke's Microscopical Observations.”
Pepys proclaims it “the most ingenious book that [he] ever read in [his] life.”
In the three years before this purchase, Pepys had tried his hand at microscopy. He
bought a book about the microscope, written by Henry Power. He also purchased a microscope
from the shop of Robert Reeve. As his diary makes it clear, Pepys had no talent for, or understanding of, optics, and he was typical of the Londoners who would buy Reeve’s instruments and
then need help in order to play with them:
… At the office all the morning. Dined at home … and agreed about getting some of
my lord’s deals on board to-morrow. Then with young Mr. Reeve home to his house,
who did there show me many pretty pleasures in perspectives* that I have not seen
before, and I did buy a little glass of him cost me 5s.
(*here, ‘perspectives’ means telescopes or microscopes) (11 February 1661)
… Thence to Mr. Reeve's, it coming just now in my head to buy a microscope, but he
was not within, so I walked all round that end of the town. (25 July 1664)
… There comes also Mr. Reeve, with a microscope and scotoscope. For the first I did
give him £5 10s., a great price, but a most curious bauble it is, and he says, as good,
nay, the best he knows in England, and he makes the best in the world. Thence home
and to my office, wrote by the post, and then to read a little in Dr. Power's book of
discovery by the Microscope to enable me a little how to use and what to expect from
my glasses. So to supper and to bed. (13 August, 1664)
… After dinner up to my chamber and made an end of Dr. Power's booke of the
Microscope, very fine and to my content, and then my wife and I with great pleasure,
but with great difficulty before we could come to find the manner of seeing any thing
by my microscope. At last did with good content, though not so much as I expect
when I come to understand it better. (14 August, 1664)
At this stage of its development, the microscope could not be used easily or successfully by the
unskilled. Reeve knew that this was not a toy for anyone who could afford it, and he was smart
enough to have available after-sales support for a fee.14 Pepys used this customer support for a
while, but soon he was happier to see the pretty pictures in print rather than try to prepare samples himself. Hooke’s Micrographia was just what he desired.
In 1668 Leeuwenhoek traveled for the first and only time to London, where he must have
seen a copy of Micrographia even though he did not mention it in his diary. As it included
drawings of fabric, Micrographia would have been of great interest to him. Leeuwenhoek used
magnifying lenses for his trade—simple magnifiers were used to examine the quality, thickness,
14
Reve’s reputation for precision instruments and service support had reached far. Huygens traveled to London to
observe a transit of Mercury from Reeve’s shop in 1661.
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density, and smoothness of cloth. The properties of the rounded glass must have captured his
curiosity, imagination, and creativity because soon he started making his own lenses. Seeing the
very small with lenses was all the rage by the time Leeuwenhoek was financially secure, settled
in his life, and ready to pursue microscopy in earnest.
Letters to the Royal Society
Jan Swammerdam, five years younger than Leeuwenhoek, was a microscope virtuoso. He
was formally schooled in anatomy, clinical practice, and dissection at the University of Leiden,
which was second to none in medical sciences in Europe. With his talent for microscopy, he laid
the foundation of entomology. Leeuwenhoek sought out Swammerdam, and Swammerdam visited Leeuwenhoek in Delft. That these two men, a cloth merchant and a scholar, would be
friends and would share optics and biology knowledge is typical of the mindset of their country
at that time. But in the early 1670’s, Swammerdam abandoned science and devoted himself entirely to religion. This was just about the time when Leeuwenhoek was at his best grinding his
powerful lenses and studying the microscopic world. Swammerdam’s legacy was very good luck
for Leeuwenhoek; the fact that Leeuwenhoek continued this legacy was great luck for biology.
Another man who knew Leeuwenhoek, and was interested in his talent for making lenses was
his friend and fellow townsman Reinier de Graaf (1641-1673). The first communication of van
Leeuwenhoek's work to the Royal Society happened because of de Graaf. De Graaf had studied
medicine at Leiden and was practicing in Delft.15 On April 28, 1673, he wrote to Oldenburg,
That it may be more evident to you that the humanities and science are not yet
banished from among us by the clash of arms, I am writing to tell you that a certain
most ingenious person here, named Leeuwenhoek, has devised microscopes which far
surpass those which we have hitherto seen…The enclosed letter from him, wherein he
describes certain things which he has observed more accurately than previous authors,
will afford you a sample of his work. …and if it please you and you would test the
skill of this most diligent man and give him encouragement, then send him a letter
containing your suggestions, and proposing to him more difficult problems of the
same kind.
(Dobell, p. 40-1)
A few weeks later, Constantijn Huygens, who was knighted by James I in 1622, wrote a character reference letter to the Royal Society on behalf of Leeuwenhoek.
Our honest citizen, Mr. Leeuwenhoek…unlearned both in sciences and languages,
but of his own nature exceedingly curious and industrious. … I trust you will not be
displeased with the confirmations of so diligent a searcher as this man is, though al15
His name is commemorated by the Graafian follicle of the ovary. He died at the age of 32, the same year that he
introduced Leeuwenhoek to the Royal Society.
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ways modestly submitting his experiences and conceits about them to the censure and
correction of the learned. (Dobell, pp. 43-44)
Leeuwenhoek’s first letter to the Royal Society contained descriptions of fungi and sporangia; the sting, mouthparts, and eye of a bee; and the entire body of the head-louse. His letter
was well received; Oldenburg translated it and submitted it to peer review, mainly to Hooke’s
scrutiny; and Leeuwenhoek’s first letter was published in the Philosophical Transactions of the
Royal Society. Many of his first observations had followed in the footsteps of items and ideas
from Hooke’s Micrographia.
Fourteen months later, on June 1, 1674, Leeuwenhoek sent another folio of six pages. He
wrote about the microscopy of blood, and the structure of bone, teeth, liver, and brain; and the
growth of the epidermis. The last sheet of the letter had a small envelope pasted to it that contained four smaller paper packets; the packets contained finely cut sections that Leeuwenhoek
had prepared by his own hand for the interest of the Royal Society. These specimens provide
great insight into Leeuwenhoek's manual dexterity as a microtomist. Interestingly his talent for
sample preparation is lost in the biographies, partly because his later discoveries were so dazzling and overshadowed everything else. What he saw under the microscope depended on how
well he had prepared the slice of the sample. Leeuwenhoek must have been infinitely patient;
these drawings alone do not do justice to his talent and devotion. Many samples followed; some
survived for three-and-a-half centuries and can still be viewed under our modern microscopes;
others were ruined by fungal growth, due to moisture, and are un-viewable now.
Pepper Water
In the three years following his first letter to the Royal Society, Leeuwenhoek had not accomplished anything beyond the ordinary to advance the science of his time. Even his exquisite
observations of the circulatory system of transparent tadpoles were “old” news. He had merely
been following in the footsteps of Swammerdam, Hooke, and other anatomists, preparing samples with better dexterity and viewing them with better lenses. Leeuwenhoek’s trailblazing began
in 1676, when he aimed his lenses at objects that were not in the repertoire of the anatomists:
cheese-rind fungi, animal sperm, bile liquid from different species of animals, crystals formed in
urine, exploding gun powder (managing not to harm himself), plaque from his teeth, melted
snow, canal water, river water, sea water, and rain water.
He recorded his observations and explanations in his diary in great detail and in a simple,
intimate, lively and straightforward way, as if talking to a friend:
14
“… the globules in the blood are as sharp and clean as one can distinguish sandgrains upon a piece of black taffeta silk, with one’s eyes, without the help of glasses.”
(Dobell, p. 331)
The detailed descriptions of his preparation steps were that of a trained scientist. The knowledgeable reader can determine that Leeuwenhoek prepared things correctly, and reproduce the
experiment with a significant degree of duplication certainty.
His meticulous writing is rivaled only by the detail of his viewings and the logic of his
method.
(26 May 1676) … it rained very hard. The rain abating somewhat, I took a clean
glass and got rain-water, that came off a slate roof, fetched it in, after the glass had
first been swilled out two or three times with the rain water. I then examined it, and
therein discovered some few very little animals; and seeing them I bethought me
whether they may not have been bred in the leaden gutters, in any water standing in
them
… the rain continuing the whole day, I took a big porcelain dish and put it in my
courtyard, in the open air, upon a wooden tub, about a foot and a half high, considering that thus no earthly particles would be splashed into the said dish. With the water
first caught, I swilled out the dish and the glass in which I meant to preserve the water, and then flung this water away, then collected water anew. Upon examining it, I
could discover therein no living creatures, but merely a lot of irregular earthly particles.
(Dobell, pp. 122-3)
He then exposed this water to the open air of his third floor room, and pondered if the little creatures would appear in the sterile water, flying in from the air. A day later, he wrote,
I fancied that I discovered living creatures, but because they were so few and not
so plainly discernible, I could not accept this for the truth. [He looked again, 36 hours
later] … I had no thought of finding any living creatures in it; but upon examining it,
I saw with wonder quite 1000 living creatures in one drop of water. [24 hours later]
… observing again, I saw animalcules in such great numbers, in the water I took from
the surface, that now they did not amount to merely one or two thousand in one drop.
(Dobell, p. 123)
Fittingly, the turning point of his career and the beginning of biology happened when he
tried to decipher black pepper. Pepper, the spice that launched a thousand ships, that made many
merchants rich, that was prominently displayed at the tables of affluent Dutch homes, and that
was conspicuously placed by the great Dutch painters in many of their still-life masterpieces, intrigued Leeuwenhoek. He wanted to understand what caused its fiery hot taste in the mouth. He
expected to see thorny protrusions, like those in a thistle or a nettle, which he presumed were
what stung the tongue. But viewing a dry peppercorn under his microscope did not reveal much.
15
He thought maybe it was the combination with water (saliva) that springs these “thorns” into action, so he soaked the peppercorns in sterile water. But when Leeuwenhoek looked at the soaked
peppercorns, instead of burry edges, he saw “little things” swimming in the water.
Of course he did not think these animalcules were responsible for the taste of pepper.
Having examined many types of water, he had developed a very good understanding of water’s
purity, depending on the source. He had used sterile water from melted snow and carefully covered the dish tightly so nothing could fly in from the air in the room. A few days later, when he
looked at the pepper water under his lens, he wrote: “… the water is so thick with them, that you
might almost imagine you were looking at the spawn of fish, when the fish discharges its roe.”
His detailed description notes reveal that he saw bacilli in that water. He experimented from
April until August with pepper water, and wrote down everything he did and saw. He next
soaked ginger, cloves, and nutmeg, not to discover why they taste as they do, but to compare
their animalcules with those of pepper water. His choice of substances is not surprising—he
was living in the era when the V.O.C. ships were ruling the spice-trading sea routes.
From his meticulous descriptions of what he observed in the spice waters and other various “natural” waters (including sea water from the beach at Scheveningen), it is apparent he saw
flagellates, ciliates, bacteria, and rotifers. Soon after his initial correspondence with the Royal
Society, Leeuwenhoek hired one of Delft’s very fine draftsmen to produce better drawings than
his own. (Dobell, p. 342) He did not make up names for what he saw; he called them ‘animalcules,’ the Latin diminutive that has a tender and affectionate sound, and he described their appearance and motion in great detail.
Leeuwenhoek’s l8th letter to the Royal Society, the pepper-water letter, is his most striking and his most highly regarded. Known as the “letter on protozoa,” it consists of 17 pages of
closely written text in a neat, small hand.16 The letter, a copy of which was also sent to Constantijn Huygens, Christian’s father, caused a sensation at the Royal Society’s reading even though
Oldenburg’s translation abbreviated many parts. (Dobell, pp. 112-166)
From the pepper-water days on, Leeuwenhoek built on his preparation expertise and experience. He conducted experiments with a wide variety of samples, at different temperatures,
letting the samples dry and then trying to reconstitute them, immersing them in different liquids
(alcohol, vinegar), depriving them of oxygen, or putting them under higher than atmospheric
16
Its details about his pepper-water research is required reading for all those interested in biology, but beyond the
scope of this paper.
16
pressure. He painstakingly recorded his detailed observations of population numbers and relative sizes.
For fifty years, up until the weeks before his death, through war and peace between England and the Netherlands, he dispatched his letters to the Royal Society regularly, with drawings
prepared by his draftsman. “’Tis my intention to inquire into these marvelous structures more
narrowly, for my own pleasure.” 20 November 1717 (aged 85)—letter to The Royal Society
When he was made a Fellow of the Royal Society (in 1680, four years after he authored
the pepper-water letter), the recognition and resulting fame did not change him. He continued to
work with the same enthusiasm, putting in longer hours now, because the recognition reassured
him that his work was meaningful and worthwhile. Many times, trustworthy clergy (principally
Protestant) were sent by scientific faculties to his house to see for themselves and to verify in
writing that what he saw was true, because the things he described were so otherworldly and incredible. He received observers graciously; they found him to be polite, eager to show and
share, and agreeable. But he became irritable when random visitors asked him for private viewings and kept him from his beloved work. He also did not care for celebrities; a Dutch citizen, he
had no training in bowing to royalty. However, when Peter the Great was passing through Delft
and asked to see Leeuwenhoek’s work, he was pleased to visit the Tsar on his canal yacht because they could converse in Dutch and because of the Tsar’s reputation. While staying for almost a year in the Netherlands, learning about shipbuilding, arsenal design, and drainage engineering, the young Tsar enjoyed fraternizing with Dutch seamen, and he learned to speak Dutch.
(Dobell, pp. 54-6)
However much he was celebrated, Leeuwenhoek went about his business being a citizen
of Delft as usual. Today’s tourist guides often mention one of his public acts, which did not involve science. When Johannes Vermeer died, Leeuwenhoek was appointed executor of his will.
This was a difficult and unenviable task. Catharina Bolnes, Vermeer’s wife, and eight children
had inherited an insolvent estate. Leeuwenhoek did his best to dispose of whatever property and
paintings remained so that the family would have the resources to survive. His contemporaries
reported that he carried out this responsibility to his friend's family in an exemplary fashion.
(Dobell, p. 35-6)
When Leeuwenhoek died, his daughter, Maria had a monument commissioned for his
burial place in the Oude Kerk of Delft. In that same church, Vermeer is also interred, but with-
17
out a monument; just an engraving on the slate slab on the floor marks the place. Maria never
married; there are no descendants of Antoni van Leeuwenhoek.
Leeuwenhoek’s Legacy
A very civil, compleasant man, and doubtless of great natural abilities; but
contrary to my expectations quite a stranger to letters…which is a great
hindrance to him in his reasonings upon his observations, for being ignorant of all other men’s thoughts, he is wholly trusting to his own. Dr.
Thomas Molyneux (1685), after visiting Leeuwenhoek
Dr. Molyneux’s comments are perhaps the most ironic sentences written about Leeuwenhoek and his work. There was no precedent to alert Leeuwenhoek that he should expect little
living things that could swim on their own to grow in sterile water with pepper soaking in it. No
one before Leeuwenhoek had seen a protozoon. With faith in natural law, he approached this
project as a disciplined scientist with curiosity and with his mind open to all possibilities. He
proposed explanations as to how these animalcules found their way into his bottles and what
made them divide and multiply. Often times he did not, and understandably could not, appreciate how significant his findings were, and what their future ramifications would be for the understanding of disease and cell biology. He kept up with the science trends and news from Leiden,
but Leeuwenhoek had little patience for those with undeserving egos:
I’ve often heard Doctors and physicians talk about things that seem to me to
have no rhyme or reason… It would have been better if they’d said ‘it’s a secret
quality’: for of course it would have been too silly for learned people just to say
‘we don’t know. (Dobell, p. 75)
Working alone, in territory where he was the first explorer, he was guided by his data.
As a firm disciple of Galileo’s legacy—data should be gathered, and the data will be the only
arbiter of the conclusion—he cared little about the turmoil regarding the discussions on spontaneous generation. His friend Swammerdam gave up science to devote himself to religion, because he could not reconcile the teachings of the bible with what he was observing in the laboratory; Leeuwenhoek had no such conflicts. In a letter to George Garden (1649-1733), the Scottish
Presbyterian minister and apologist of the religious fanatic Antoinette Bourignon who was instrumental in causing Swammerdam to give up science, Leeuwenhoek made his point boldly:
… my efforts are ever striving towards no other end than to set the truth before my
eyes, to embrace it, and to lay out to good account the small talent that I have received: in order to draw the world away from its heathenish superstition, to go over
to the truth, and to cleave unto it. (Dobell, p. 74)
18
Leeuwenhoek observed nature and set forth in his journal conclusions that he believed
were supported by the data. If the data later proved him wrong, if his findings contradicted his
earlier ideas and explanations, he was honest and willing to change his mind. He gladly and
readily subjected his observations to peer review—mostly to the Royal Society members.
Few scientific workers have had so clear a concept of the boundary between observation
and hypothesis, fact and fancy. There was nothing dogmatic, nothing in his agenda, other than
searching for the truth objectively; this is the hallmark of a scientist. Leeuwenhoek conducted
his research in a truly scientific manner. To know how he worked is to know the real meaning of
the much-abused term “scientific research.” This is Leeuwenhoek’s real gift to us, his real legacy—not the microscope lenses he made and used.17
Products of Their Times
“What other people [but the Dutch] has written its history in art?” Théophile Thoré
The study of light by amateur scientists influenced the artists’ techniques; light was also
big business for science in the seventeenth and eighteenth centuries. Galileo profited by selling
his telescopes to the Medici family, who used them for profit as well. Newton got his foot in the
door of the Royal Society not as a result of his work in calculus, but with his reflective telescope.
A reflective telescope (with one curved mirror and one lens) has half the length for the same
power as a refractive telescope (with two lenses). The reflective telescope is conveniently portable on ships, with brighter images due to less absorption and with minimal rainbow-edge distorted images. Oldenburg and Viscount Brouckner (Commissioner of the Navy Board) immediately recognized its strategic potential. Stargazers were only a minority of users; sighting the
enemy ship’s flag was a more pressing and vital priority.
The Scientific Revolution 18 is a term much misapplied temporally and much misplaced
geographically. It is not a revolution, as it did not happen in a short period of time, abruptly or
dramatically; it took almost a century-and-a-half to unfold: from Copernicus’ mathematical
model (1543), through Brahe’s data, Galileo’s experimental evidence, and Kepler’s laws, to the
final Newtonian synthesis (Principia, 1687). Even though the Scientific Revolution started in
Italy, science found suitable ground for its nurture, growth, and maturation in northwestern
Europe. Supported by the economies of prosperous nations, scientific pursuits flourished among
17
Some of his misinformed biographers hail him as the inventor of the microscope.
The appropriation of the word ‘revolution,’ (from Copernicus’ book title, On the Revolutions of the Heavenly
Orbs), to denote a ‘bloody upheaval’ spoiled a beautiful word of mathematical physics.
18
19
open-minded citizens whose intellectual activities were not confined by organized religion.
While they were spiritual and God-fearing people, the Dutch and British saw no conflict between
science and religion. By the eighteenth century, at the time of the Enlightenment, unbiased
knowledge was valued for its utilitarian potential in everyday life.
On the occasion of an honorary degree awarded to him, Leeuwenhoek wrote to the faculty at the University of Louvain, on June 12th, 1716,
My work, which I have done for many a year, was not pursued in order to gain the
praise which I now enjoy, but chiefly from a craving after knowledge. ….whenever I
found anything remarkable, I have thought it my duty to put down my discovery on paper, so that all ingenious people might be informed thereof. (Dobell, p. 83)
As Dobell summarized, "… all his long life Leeuwenhoek kept on asking questions of nature…and trying in his simple way to understand her answers." (p.76)
It is fortunate for us that the intellectual, social, and economic circumstances were suitable for supporting Leeuwenhoek’s work and talent, and for permitting the Royal Society to establish the model of scientific truth as the result of verifiable data.
Note: This paper is a synthesis of what I learned as a participant in the 2007 N.E.H. Summer
Seminar “The Dutch Republic and Britain: The Making of Modern Society and a European
World-Economy,” led by Professor Gerard M. Koot. It is by no means an exhaustive or
complete account. It is intended to give only a taste of the world in which Leeuwenhoek and
the Royal Society started our modern science practices; if it whets the appetite for more information, then the books listed in the bibliography below will be a good starting point.
Details about the men of the Royal Society I found in the Oxford Dictionary of National Biography, which was available to us at the library of the Institute of Historical Research, University of London. Dobell’s book is the best scholarly and meticulously researched biography of Leeuwenhoek. (See also Brian Ford's Leeuwenhoekiana article for
commentary on Dobell.) Jardin’s book will be of particular interest to those interested in the
history of science. As of 2007, Israel’s is the only comprehensive book I have come across
which covers in detail the intellectual and scientific / technological contributions of the
Dutch Republic. Berg sheds new light on the relationship between social history, economic
history and the role of technology. The books by deVries and Wrightson are excellent background reading regarding the economic and social history of the era.
BIBLIOGRAPHY
Berg, M., The Age of Manufactures, 1700-1820: Industry, Innovation and Work in Britain (London: Routledge, 2nd ed. 1994).
de Vries, J., The Economy of Europe in an Age of Crisis, 1600-1750 (Cambridge: CUP 1976)
Dobell, C., Antony van Leeuwenhoek and His Little Animals (New York: Russell &Russell, 1958)
20
Ford, B. J., “The Leeuwenhoekiana of Clifford Dobell (1886-1949)”, Notes and Records of the
Royal Society of London, Vol. 41, No. 1. (Oct., 1986), pp. 95-105.
Ford, B. J. “The van Leeuwenhoek Specimens”, Notes and Records of the Royal Society of London, Vol. 36, No. 1. (Aug., 1981), pp. 37-59.
Hall, A. R., “The Leeuwenhoek Lecture, 1988. Antoni van Leeuwenhoek 1632-1723” Notes and
Records of the Royal Society of London, Vol. 43, No. 2, (Science and Civilization under William and Mary. Jul., 1989), pp. 249-273.
Israel, J., The Dutch Republic: Its Rise, Greatness, and Fall 1477-1806 (Oxford: Clarendon Press,
1995)
Jardine, L., Ingenious Pursuits: Building the Scientific Revolution (New York: Nan Talese, 1999)
Steadman, P., Commentary on "Vermeer and the Camera Obscura: Some Practical Considerations", Leonardo, Vol. 32, No. 2. (1999), pp. 137-140.
van Seters, W. H., “Antoni van Leeuwenhoek in Amsterdam”, Notes and Records of the Royal
Society of London, Vol. 9, No. 1. (Oct., 1951), pp. 36-45.
Wrightson, K., Earthly Necessities: Economic Lives in Early Modern Britain (New Haven: Yale
UP, 2000)
In the year 1632...
• Vermeer was born in Delft the same week
as Leeuwenhoek.
• Spinoza was born in Amsterdam, four
weeks later.
• John Locke was born in Somerset.
• Rembrandt painted "Dr. Tulp's Anatomy
of the Arm."
• The Spanish were defeated at Maastricht.
• The V.O.C. reached its peak.
• The Athenaeum Illustre was founded in
Amsterdam.
• Galileo published "Dialogo sopra i due
sistemi del mondo."
Leeuwenhoek's authentic portrait,
by Johannes Verkolje.
21
Possibly an early Vermeer,
modeled after Leeuwenhoek's
activity and shop.
.
Relative size of a Leeuwenhoek microscope.
22
From Brian J. Ford’s web page:
Ford
http://www.brianjford.com/wavintr.htm
© Brian J.
The last page of the 1673 Leeuwenhoek's letter to the Royal Society had these paper
packets with “prepared specimens.” They still survive today, 350 years later.
Original specimens of algae from the 17th century
were found in their original packets. The three
samples of aquatic algae had been dried to a papery
film. The material is reconstitute-able, and portions
of it was studied with our modern microscopes.
Folded packets containing sections
of cotton seeds, safely stored in
paper envelopes, were attached to
one letter.
Research at Utrecht university confirmed that the
image quality of simple
microscopes is very high.
Here is an unmounted and
unstained blood smear.
The erythro-cytes,
rounded discs, are clearly
resolved. A white cell is
shown top, right of center.
Its lobed nucleus is visible. This is a remark-able
result for a single-lens microscope of the late seventeenth century.