How did Leeuwenhoek send and receive letters?

How did Leeuwenhoek's letters get to England?

In his letters, he never mentioned using the postal service. If he had sent his letters that way:

  • After 1668, they would have gone by barge to either Maassluis (more directly) or Rotterdam and from there to den Briel and on to Hellevoetsluis.
  • Boats carrying mail and later passengers went daily between Hellevoetsluis and Harwich in England. From there, the mail went by coach to London.
  • One way, it took four days and later three days for the letters to make the trip. Because England still used the Old Style (Julian) calendar, ten days behind Holland, this speedy service meant that Leeuwenhoek's letters were frequently read on a date in London several days earlier than the date in Delft on which it was sent.

Letters going in the other direction, to Leeuwenhoek, were supposed to go via Amsterdam, which held monopoly rights. However, disputes, especially between Amsterdam and the up-and-coming Rotterdam, let the letters and copies of Philosophical Transactions reach Delft more directly. See the section on 17th century European postal systems below.

Private messenger

Leeuwenhoek's letters and the replies from the Royal Society several times mentioned the names of private messengers and a mailing address in Rotterdam.

In the letter of 1674-04-16 (AB 6) to Henry Oldenburg, Leeuwenhoek wrote:

My last letter to your address was sent on the 7th instant by means of Mr. Adriaen van Beijeren, and I have no doubt that Your Honour received the same. And since Mr. Justus van Conincxbrugh well known to me (and of gentle birth) has made it known as his intention to spend most of his time this summer in England, I cannot omit informing you, and begging you to hand any letters you may want to send to me to Mr. van Conincxbrugh aforesaid, in which case these will reach me safely.

Adriaen van Beijeren (1651-1683) was a little boy when Leeuwenhoek bought the house two doors down on the Hippolytusbuurt in 1655. His father, Abraham Adriaan, who had died in 1653, ran a draper's shop in the Rode Zee similar to the one Leeuwenhoek opened in the Gulden Hoofd. It is not known why Adriaan would be going to London at age 23, but it would have been easy enough for him to do a favor for a neighbor. Adriaan's mother was Agatha Cornelis van Lodensteijn, whose father had served as magistrate (schepen) and orphan master (weesmeester).

Justus Doesen van Conincxbrugh (1650-1678) was born in Zoetermeer, about 6 miles (10 km) northeast of Delft. His mother was Machteld Cornelis van Lodensteijn, who like her sister Agatha had grown up in the Rode Zee. By the time Leeuwenhoek bought the Gulden Hoofd, Machteld was a married 35-year-old living in Zoetemeer with a four-year-old son. Justus no doubt spent some time at the house of his aunt Agatha and cousin Adraien, so Leeuwenhoek had known him most of his life. When Justus returned from his summer in London, he married Catharina Daniels Planck in Amsterdam and died there a year later at age 28.


In Letter 5 of 1674-07-06 (AB 9) to Henry Oldenburg, Leeuwenhoek wrote:

The present serves to let you know that I have handed to Mr. Adriaen Boogaert, Seigneur of Belois, Director of the East Indian Company in this town, a parcel containing a tin case in which I put several glass tubes, invented by me for the observation of milk, blood, brains, spinal marrow, etc., in order that the Curious Gentlemen may share my observations of blood, etc. My humble request is that you will send somebody to the above-mentioned Seigneur of Belois for the packet.

Adriaen Boogaert (1634-1708) was a Delft magistrate from 1665 to 1668, so Leeuwenhoek probably got to know Boogaert in the Stadhuis. In 1656, Boogaert married his first cousin Anna Briel. Boogaert was on the wrong side in 1672, the Disaster Year, when Prince Willem III carried out a wetsverzetting (changing of the legislative) and replaced parts of the city council (Vertigraad) of the large Dutch cities, Delt and Adraien Boogaert among them. Perhaps it is an indication of Leeuwenhoek's political sympathies that he was asking Boogaert to carry packages to London, although the letter has no additional details about where the Royal Society's messenger would find Boogaert.


In the letter of 1676-01-22 (AB 20) to Henry Oldenburg, Leeuwenhoek wrote:

Transaction N. 117, issued in the month of September, should have been brought to me by a merchant who was in London, at the end of October or the beginning of November, as well as Transaction 113, but he did not bring the same. You have the kindness to offer me the Transactions, but that you fear the postage will be too high. Sir, if you would be so good as to send me the Transactions No. 113 and 117 and the following that may be issued, please have those brought to St. Catrijn in de dortse boeijer where all the skippers stay who sail to Rotterdam, and do this every three months or as you please. You will do me a great favour, and I will gladly reimburse the expenses.

The merchant and skippers have remained anonymous. In a postscript, Leeuwenhoek wrote:

If you have the goodness to send me these Transactions by a Rotterdam skipper, please write the address as follows:

Juffr Catatarina Leeuwenhoeck
Wede. van Sar. Claes van Leeuwen
op de Hoogh-straet in het Oude
Gemeenlants Huijs. Tot Rotterdam.

Leeuwenhoek's sister Catharina (here misspelled by Leeuwenhoek) still lived in Rotterdam. By the early 1680's, she had moved back to Delft, but her eldest daughter Rijckje remained in their house in Rotterdam.


In Letter 25 of 1678-05-31 (AB 39) to Nehemiah Grew, Leeuwenhoek wrote:

If you only send me a letter, I shall expect it by post to Delft, but if you add some of the Transactions, I shall expect them via Rotterdam, like last time.

The footnote in Alle de Brieven / Collected Letters explains that a yacht stationed in the mouth of the Maas (Meuse) was responsible for hailing ships coming into Rotterdam for letters, etc. A smaller boad took the letters ashore, where a horseman carried them to the post-office between 's-Gravesande and Maassluis. From there the post-boy carried them to Rotterdam. From there, the letters would go straight to Delft by post.

Packages were treated differently. Because they were too heavy for the post-boy, the ship took them to Rotterdam. Thus, Leeuwenhoek would obtain his books sooner, for he would send somebody to Rotterdam for them or fetch them himself.


In the letter of 1680-01-16 (AB 55) to Robert Hooke, Leeuwenhoek wrote:

This only serves to inform you that on Saturday (after having sent you on the previous Friday the drawings of some kinds of wood) I received the Philosophical Collections No. 1, besides a list of the members of the Royal Society, addressed to Mr. Isaac Velthuysen, a Rotterdam merchant. I was very glad to have them, but wondered why there was not in addition a short note mentioning the sender, that I might thankfully acknowledge the receipt. I hope you will inform me on this point when you send an answer to my last letter.

Isaac Velthuysen (1652-1739) was the superintendent of Rotterdam's asylum for old women and justice of the peace (1689-1690). In 1713, he was elected a magistrate (schepen) of Rotterdam. He made his living trading with foreign countries. Among other htings, shipped hides from Germany to England


In a letter of 1680-10-18 from Christiaan Huygens to his brother Constantine, then in London, Christiaan wrote (my loose translation):

Je viens de recevoir une lettre du Sr. Leeuwenhoeck, qui me mande qu'il vous a adresse par le Beurtman de Rotterdam a Londres (Schipper Jeroen Vinck) 4 exemplaires reliez de ses dernieres observations, pour la Reine, qui en a eu d'autres cy devant a ce qu'il dit, pour vous, pour le Dr. Stanley et pour la Societé R. lequel dernier le dit Docteur pourra faire tenir a ces Messieurs, et il pourra en meme temps leur faire les plaintes de la part de l'autheur, qui a sept lettres qu'il leur a ecrites, dont j'ay eté porteur de la derniere, n'a jamais eu de response, ce qui marque que nihil est quod agatur apud vos.

Je m'acquite de ce qu'il m'a priè en vous donnant cet avis. Faites moy reponse je vous prie quand vous en aurez le loissir.

I have just received a letter from Mr. Leeuwenhoeck, who tells me that he has sent to you by the beurtman of Rotterdam in London (skipper Jeroen Vinck) 4 copies of his last observations, for the Queen, who had some other words in front of what he says, for you, for Dr. Stanley, and for the Royal Society, which the last one says the Doctor will be able to hold to these gentlemen, and he will be able at the same time to make complaints on behalf of the author, who has written seven letters to them, of which I was the bearer of the last, has never had a reply, which indicates that nihil is quod agatur apud vos.

I am grateful for what he has asked me in giving you this opinion. Make an answer I beg you when you have it.

I can find references confirming that Jeroen Vinck was a boat skipper, but nothing about this life.

In the late 15th century, the Dutch began developing the beurtvaart system for transporting goods and mail via sailboats adapted to the challenges of Holland's inland waterways. The Wikipedia notes that "It was a form of packet trade and a precursor of public transport. The beurtships transported passengers, livestock and freight along fixed routes at fixed prices."

Wikipedia: en | nl


In the letter of 1697-03-25 (AB 183) to members of the Royal Society, Leeuwenhoek wrote:

On the 26th of the preceding month [March] I myself delivered to the Regular Skipper from Rotterdam to London a small parcel with the address: To the Secretary of the Royal Society at Gresham College, via Skipper Huijbert den Baas, which parcel only contains my latest printed Letters which have been translated into the Latin Language. I hope it will duly reach you.

I can find nothing furth on Huijbert den Baas. The printed letters must be Continuatio Arcanorum.

At their regular weekly meeting on June 23, 1697 (July 3 in Delft), the Royal Society letter read this letter. The members requested that Robert Hooke review the book (Journal Book Original, vol. 10, p. 39), which they did on the four successive meeting through July 13 (Journal Book Original, vol. 10, p. 42).

Of the 15 letters published in the Continuatio Arcanorum..., numbered by L. himself, ranging from Letter 154 [93], of 18 August 1695, Collected Letters, vol. 11, pp. 55-63, up to and including Letter 177 [107] of 27 September 1696, in the present volume, only one was addressed to the Royal Society, to wit Letter 169 [102] of 10 July 1696, idem, vol. 11, pp. 301-327. For the members of the Royal Society therefore, the contents of these letters were practically wholly new.


In Letter 109 of 1697-09-03 (AB 187) to Jan van Leeuwen, Leeuwenhoek wrote:

I have received the work of Malpighi published after his Death, and later on a small Bundle of Philosophical Transactions, addressed to Rotterdam to Mr Philip van Leeuwen, and since then two more Transactions from the accurate and very observant Doctor Harwood, Member of the Royal Society.

Philip van Leeuwen was the son of Leeuwenhoek's niece Rijckje van Leeuwen. John Harwood (1661-1731) was an active, though non-publishing, member of the Royal Society after 1687.


Postal systems

Europe's international postal systems changed during Leeuwenhoek's lifetime, as did the system within the Dutch Republic.

Before the 17th century, both secular and religious governments had systems to carry messages between royal courts and between monasteries. Since literacy wasn't widespread outside those locations, private messaging was done ad hoc either by giving a message to someone or by hiring someone to take it. In Europe, the Tassis family (later using the name Thurn und Taxis) developed an international network throughout the Holy Roman Empire. Brussels was one of the major hubs. After 1506, the system was opened to use by private individuals.

Before the end of the Eighty Years' War, Brussels was part of the Spanish enemy's empire. It wasn't until 1648 that the Dutch were able to establish a republic-wide system. The regular boat traffic on the major canals connecting the cities made the Dutch system the most efficient inter-city system in Europe.

Postal carrier on horseback with horn, 1668

Within each city in the Republic, economic prosperity developed hand-in-hand with reliable written communication. Harold Cook's Matters of Exchange develops that idea in detail. Cook argues that reliable written communication also enabled the rise of what we now call science. Remember that Leeuwenhoek wrote only letters, and that his two major means of communicating with the world depended on postal services.

  • Philosophical Transactions was distributed via the postal services.
  • People rountinely copied Leeuwenhoek's letters and articles by hand and sent them to others via the postal services.

Even at the time, those involved referred to the Republic of Letters as a supra-nation that resulted from efficient postal services, reliable and speedy. It let Leeuwenhoek stay in Delft, arguably the center of the civilized world at the time, and receive information from all over Europe.

After 1648, messengers on horseback could more safely carry their letters and parcels along fixed routes at fixed times. Given the decentralized nature of power in the Republic, it is not surprising that each city had its own system. In Delft, the city government had messengers (boden) to carry information to the people and from them back to the officials in the Stadhuis as well as a traveling messenger to other cities.

For mail between individuals, Delft had two messenger services by the 1670's, when Leeuwenhoek became active. In the summer of 1678, the mayors combined the two under the management of Lambert Twent. After that, Leeuwenhoek would have used Twent's service.