The tables and the accompanying discussion of van Leeuwenhoek's letters have six main sources:
Alle de Brieven / Collected Letters
About 200 of van Leeuwenhoek's original letters, in Dutch, some with specimens, are in the possession of the Royal Society. The end of the letter of April 15, 1673 is shown on the right.
A little more than half of his letters were translated and then extracted or abstracted as articles in the Society's Philosophical Transactions.
In addition, when Dobell wrote his biography in 1932, the University of Leiden had eight other manuscripts, the National Library at Florence had fifteen addressed to the Florentine scholar Antonio Magliabechi, and the Municipal Museum in the Hague had four. Dobell also consulted one among Leibniz's manuscripts in Hanover, Germany.
The table below summarizes what I see as seven periods of van Leeuwenhoek's publishing career, according to who was the editor of Philosophical Transactions.
The far right column shows the number of articles written by van Leeuwenhoek and published in Philosophical Transactions. Note the two periods when Halley was editor, in red.
The large tables below expand this summary to a yearly record of van Leeuwenhoek's publication history.
van Leeuwenhoek's publishing history
Antony van Leeuwenhoek wrote only letters, hundreds of them. He wrote them in Dutch, the only language that he knew. These letters, his complete scientific work, are our only access to his work and ideas.
Many of his letters were published, at least in part, in English translation. Others were collected and published in pamphlets and books by van Leeuwenhoek, in the original Dutch and in Latin translation, with irregular paginations and different illustrations. Many of the English translations were then translated into French and published in the French Academy's Journal des Scavans. At the end of Dobell's biography, his discussion of van Leeuwenhoek's letters reveals the "grievous difficulty" of grappling with all the versions published during van Leeuwenhoek's lifetime. Frank Egerton calls it a "bibliographic nightmare".
In the 1670's, van Leeuwenhoek made what we now consider his most important discoveries: protozoa, bacteria, red blood cells, and sperm. Even ten years earlier, his best way to tell anyone would have been to send "learned letters" to the people scattered around Europe who seemed interested in such things. Perhaps they would find his observations worth copying and passing on to other learned friends.
Knowing no language other than Dutch, especially Latin, van Leeuwenhoek would have been severely limited as a participant in this primitive knowledge network.
By 1673, fortunately, van Leeuwenhoek had another outlet, what we now call the "learned society". The Royal Society in London, the first, was a more organized knowledge network using the latest technology, the printing press.
The Royal Society, a radical, upstart group housed in Gresham College, preached experiment and observation, not theory. The members advocated Francis Bacon's inductive reasoning based on observation and experiment. Their meetings featured live demonstrations of experiments by Curator of Experiments Robert Hooke.
According to Sprat's History, they rejected:
amplifications, digressions, and swellings of style ... bringing all things as near the Mathematical plainness, as they can: and preferring the language of Artizans, Countrymen, and Merchants, before that, of Wits and Scholars.
This learned society produced a journal, the first of its kind. Every month, several articles were published and once a year, they were collected into a volume. Around 1,200 of each monthly number were printed and distributed throughout the world. This journal, Philosophical Transactions, was edited and paid for by its founding editor, Henry Oldenburg. It was the one and only place where, at that time, the plain-speaking, monolingual, uncredentialed, non-theoretical foreigner van Leeuwenhoek, very much the outsider, could tell the world about the wriggling, swimming things, the multitude of little animals, that he was seeing through his tiny lenses.
The Royal Society had been meeting for thirteen years when they got van Leeuwenhoek's first letter in 1673. The Society had an early triumph with Hooke's Micrographia in 1665 and it survived founding editor Henry Oldenburg's imprisonment for espionage in 1667. Philosophical Transactions was beginning its eighth year of publication in 1673:
giving some accompt of the present undertaking, studies, and labours of the ingenious in many considerable parts of the world.
The next fifty years of van Leeuwenhoek's relationship with the Royal Society is divided into seven periods. This web has a page discussing each period in more detail, linked to the dates on the table on the right.
Note on the tables below displaying van Leeuwenhoek's publication history:
Letters were not published in Philosophical Transactions in the same year as they were written. As much as 13 years passed between; letters from April and May 1680 were not published until 1693.
The individual numbers of a given volume continued to be published in the subsequent year. For example, the last two numbers, 141 and 142, of volume 12, edited by Grew after Oldenburg's 1677 death, were issued in 1678 and 1679, even though the official date of volume 12 is 1677. This pattern of a volume every other year is especially noticeable during Sloane's editorship.
The first three columns in the tables below note the tenure of the editors of the Royal Society's journal, Philosophical Transactions, and its volume.
The fifth, sixth, and seventh columns show the number of letters:
written and eventually published, according to Cole
published by the editors in Philosophical Transactions
published either by Hooke in Microscopium and in Philosophical Collections or by van Leeuwenhoek in Dutch editions
the Dutch editions were more or less paralleled by Latin edition, none of which are noted here
Van Leeuwenhoek's Publishing History