Welcome!

What do you do when you see things that no one has ever seen before?

When you show these things to the people around you, they don't see them. Or they can't see or won't see them.

So then what do you do?

This web explores how a curious, methodical Dutchman responded to just that situation more than three hundred years ago.

Delftware
17th century tile
made in Delft

Below is a brass microscope made by hand by Antony van Leeuwenhoek in the late 1600's. The plate is about 5 cm (2 in) high. It will fit easily into the palm of your hand. The spherical glass lens is a little more than a millimeter (4/100th's of an inch) in diameter.

This microscope was an order of magnitude better in terms of magnification and resolution than any other microscopes available in the 1600's.

van Leeuwenhoek microscope

What else is here?

In addition to the main series of videos/web pages, you will also find other resources about van Leeuwenhoek's life and times.

Letters

His three hundred letters over fifty years divided into seven time periods according to who was editor of the Royal Society's Philosophical Transactions.

Period
1 - 1673-1677
2 - 1678-1682
3 - 1683-1685
4 - 1686-1692
5 - 1693-1714
6 - 1715-1719
7 - 1720-1723

Publications

How to find your way among the various editions and translations.

Bibliography

Annotated print and online sources for information about van Leeuwenhoek.

Maps

What the world looked like to the Europeans of van Leeuwenhoek's time.

Videos

The short videos presented separately and combined into one long video - coming soon!

Dutch

The language, both now and in the 1600's.

Bookstore

Learn more about van Leeuwenhoek's life and times. Reviews and recommendations.

About

Who made this web? Why? How? What about copyrights?

First Translation

This web features the first published English translation (as far as I can tell; corrections welcome) of some of van Leeuwenhoek's letters. Beginning on the Period 6 page, I translated van Leeuwenhoek's summaries for the two dozen letters in Send-Brieven / Epistles that also have illustrations.

For a discussion of the difficulties of translating van Leeuwnhoek, see the Dutch page.

Antony van Leeuwenhoek

1632 - 1723
Delft, the Dutch Republic

Verkolje portrait of AvL

Portrait by Jan Verkolje

What you will find here

The heart of this web is a series of web pages and complementary short videos. The main text of the web pages is almost identical to the narration in the videos.

	Lens on Leeuwenhoek
	Overview of the life, times, and work of the developer of the single-lens microscope and the first person to see bacteria and protozoa.
	The Most Prosperous Country
	The Dutch Republic during its Golden Age was the world's most prosperous and learned country.
	The Curious Observer
	The early life of Anthony van Leeuwenhoek, cloth merchant and haberdasher, citizen of Delft.
	Tiny Lenses
	The three methods van Leeuwenhoek used to make his lenses: grinding, blowing, and drawing.
	Tiny Microscopes
	Van Leeuwenhoek made palm-sized microscopes from brass and silver to hold his tiny lenses and position his specimens.
	Using the Microscopes
	With difficulty, van Leeuwenhoek used his microscopes to make the world of microorganisms visible.
	Counting the Animalcules
	How small? How many? How van Leeuwenhoek calibrated and counted the multitude of tiny things he discovered.
	"No Longer Any Doubt"
	How the Royal Society validated van Leeuwenhoek's extraordinary claims.
	As Science Began
	How the self-educated van Leeuwenhoek helped give birth to the scientific method, especially peer review.
	The Theater of Nature
	What van Leeuwenhoek accomplished. How he was received by the people of his time. What happened to his microscopes.

He wrote about the day he made a startling and unexpected discovery:

In the year 1675, about half-way through September (being busy with studying air, when I had much compressed it by means of water), I discovered living creatures in rain, which had stood but a few days in a new tub, that was painted blue within.

This observation provoked me to investigate this water more narrowly; and especialy because these little animals were, to my eye, more than ten thousand times smaller than the animalcule which Swammerdam has portrayed.

"Living creatures in rain water"? "Ten thousand times smaller"? They had always been there, but no human had ever seen them until that September day.

Who was this man with this chatty writing style about tiny animalcules?

How did he manage to stumble onto this Eden, where he was Adam, surrounded by animals with no names?

Why do we remember Antony van Leeuwenhoek today?

What can he teach us about how to explore our own worlds?

What do you do when you see things that no one has ever seen before?

Wat doe je als je dingen zie dat niemand ooit heeft gezien?

Best of the Web

Warnar Moll has the best single site on the Web for information about van Leeuwenhoek.

Other recommendations:

wikipedia screen shot
Wikipedia biography
en | nl

Brian Ford was able to use an authentic van Leeuwenhoek microscope to look at authentic van Leeuwenhoek specimens uncovered in the archives after three hundred years. His web site records what happened.

Why we remember van Leeuwenhoek today

This linen merchant and civil servant from Delft developed a tiny single-lens microscope that let him become the first human to see the hidden world of microorganisms. His fifty years of letters, many to the Royal Society of London, recorded his observations of protozoa, bacteria, spermatozoa, and blood flow in capillaries, among many other things.

Recommended

Dobell bio cover

Antony Van Leeuwenhoek and His "Little Animals"
by Clifford Dobell

From 1932, but it has not been surpassed. If you're going to read only one biography, make it Dobell.

Did you know ...?

In the history of the British Royal Society's journal Philosophical Transactions, van Leeuwenhoek, with over a hundred articles, is its most frequently published author, by far. Learn more on the Publications page.

Phil Trans cover