Wrote Letter 2 of 1673-08-15 (AB 2) to Henry Oldenburg

August 15, 1673
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Leeuwenhoek's summary

The letter opens (text from Alle de Brieven / Collected Letters vol. 1, p. 43):

I have several times been pressed by various gentlemen to put on paper what I have seen through my recently invented microscope. I have constantly declined to do so, first because I have no style or pen to express my thoughts properly, secondly because I have not been brought up in languages or arts, but in trade, and thirdly because I do not feel inclined to stand blame or refutation from others.

Pressed by Dr. Reg. de Graaf I have thought better of my intention and given him a memorial of what I observed concerning mould, the sting and some articulations of the bee, and also the sting of the louse, which memorial he (Mr. de Graaf) has forwarded to you and informed me of your reply. I see from this that my observations were not unwelcome to the Royal Society, and that these Gentlemen were anxious to see the figures of the sting and articulations of the bee which there I state to have seen.

As I am not a draughtsman myself, I have had them drawn for me, but the proportions have not been observed as accurately as I could have wished. Also each figure has been seen and drawn through a particular magnifying glass; I am sending you these enclosed.

I beg you and the Gentlemen under whose eyes this happens to come, to bear in mind that my observations and opinions are only the result of my own impulse and curiosity and that there are in this town no amateurs who, like me, dabble in this art. Take my simple pen, my boldness and my opinions for what they are; they follow without any particular order.

Text of the letter in the original Dutch and in English translation from Alle de Brieven. The Collected Letters at the DBNL - De Digitale Bibliotheek voor de Nederlandse Letteren

Leeuwenhoek wrote this letter to Henry Oldenburg about the bee; movement of liquids in wood and food in louse; composition of air.

Leeuwenhoek's second letter:

  • followed up on the observations from his first letter
  • added more observations of the bee
  • added observations about wood
  • described his experiment with capillary tubes to learn how fluids rose in trees
  • enclosed a drawing of the tubes he used

Of 3 ink figures, only 2 were published in Philosophical Transactions, both of straight capillary tubes (right). The third is also a capillary tube, but it is bent in a U-shape. The much shorter part is thicker and has a plunger inserted into the open end.