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Leeuwenhoek Notes

There are lots of places focused on his biological observations - I'm looking at the technology he is familiar with - such as his use of a lath - use of capillary and then a new system for fluids.

Things he was familiar with

"Antichamber, and is very close joyned together with Wainscot, having no other opening than one hole of an inch and a half broad, and 8 inches long, [through which the wooden spring of my lathe 30 ) passes] towards the street furnisht with 4 windows, of which the two lowermost open inwards..."
"30 This wooden spring must have been that of a "pole~lathe", fastened to the ceiling. Not having room enough in his closet, L. passed the spring through a slit in the partition. By moving the treadle the axle - round which the cord~ band is passed two or three times - moves backward and forward. Lathes have been in use since the 16th century. From that time "pole~lathes" have sometimes been called simply "lathes"."

Observation of fluids

Originally in what I think were hand drawn capillary tubes - made just before the experiment (would thus be sterile and free of dust). In 1675-01-22 letter he talks of coming up with a new method that he won't share.

Observational limits

For reference - Red blood cells are about 6-8 μm in diameter and 2-3um thick. Hair is about 40um in diameter, paramecium about 200um long. Bacteria 1-2um. From 1677-05-15 " 15 or 20 times finer than a single thread of Silkworm" - about 4um

Methods kept secret


"... Sir, be assured that my microscope showed the same as clearly and distinctly as one can imagine to see figures with the naked

eye but the fault is mine, since I cannot draw and on the other hand since I have the intention to keep the method I use secret from everybody. ..."


"My method for seeing the very smallest animalcules and eels I do not impart to others, nor that for seeing very many animalcules all at the same time, but keep that for myself alone."


"much more. when I said. [there were in it two or three kinds of

much smaller animals besides. which did not appear to him, and which I could observe by other glasses and other methods. which I still reserve to my self alone ] 9 ) . "

1678-03-18 Not portable:

" I hardly see my way to do this as I require my customary seat and instruments, which I cannot place everywhere for use. "

Book and other Dates

A more complete - but with more noise -timeline can be seen here

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