Wrote Letter 14 of 1676-02-22 (AB 21) to Henry Oldenburg
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 hair, cow skin, horn, and bone, inviting Hooke's response.
He wrote about hair in direct response to Oldenburg's request. At the end of January, Leeuwenhoek had written
I also have written down my speculations on the reason why one hair curls, another hangs down, and how we imagine to see a cavity in the hair of any animal. If you want to see the drawing of two hairs with the roots, I will send it to you.
In early February, Oldenburg replied that he -- and Robert Hooke -- did indeed want to hear about Leeuwenhoek's observations of hair, so Leeuwenhoek sent this letter right away.
Oldenburg's letter was dated February 3 in London, which would have been February 13 in Delft. Allowing eight days for delivery, Leeuwenhoek received it around February 21. This response, then, was written, or at least dated, the following day.
