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.
17th century tile
made in Delft
Below is a silver magnifying glass aka microscope made by hand by Antony van Leeuwenhoek in the late 1600's (click to enlarge). The plate is less than 50 mm (2 in) high. It will fit easily into the palm of your hand. The single glass lens, almost spherical, 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 of the compound microscopes available in the mid-1600's.
What else is here?
Site Guide
How to use Lens on Leeuwenhoek. Abbreviations, spelling, and other trade-offs and compromises to adapt Leeuwenhoek's messy life to the rigors of the database.
Resources
Lists of primary sources in manuscript and print as well as secondary literature and tools for researchers into Leeuwenhoek's life and times.
Search
Find information by search term.
Dutch
Learning the Dutch language, with an emphasis on the 17th century.
About
Who made this web? Why? How? What about copyrights?
Featured page
When Leeuwenhoek's daughter Maria died, she left behind:
* more than ten thousand guilders in cash
* 70 bonds and other financial instruments paying her over three thousand guilders per year
* almost two thousand tea cups
* dozens of her father's instruments and tools
Learn more about The estate of Maria van Leeuwenhoek.
This web, the online record of an ongoing research project, will continue to grow and develop. Instead of pages organized by chapters, it has a database organized by a taxonomy; its top level is shown in the links across the top.
The author is responsible for accuracy of the information on this web. Corrections are welcome.
Why we remember 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 red blood cells flowing through capillaries, among many other things.
Recommended
Antony van Leeuwenhoek
and his "Little Animals"
by Clifford Dobell
First published in 1932, but it has not been surpassed. If you read only one biography, make it Dobell's.
Video Overview
of the life, times, and
accomplishments of
Antony van Leeuwenhoek
(< 8 minutes)
Featured Letter
Letter 28 of April 25, 1679, to Nehemiah Grew
The earliest written of the 165 letters that he self-published. His summary:
Dissections and discoveries of the living little animals in the milt of male seed of fish, and in the testicles of animals. More than ten times as many living animals come from the milt of a cod as there are people living on the Earth. Read more
Featured Figure
The testicle of a dog after the second skin had been taken off
Did you know ...?
In the history of the British Royal Society's journal Philosophical Transactions, Leeuwenhoek, with over a hundred articles, is its most frequently published author, by far.
Leeuwenhoek 117
Martin Lister 87
Edmond Halley 81
Robert Boyle 58
