Henry Oldenburg wrote Letter L-023 to Leeuwenhoek in response to his Letter L-021 of 1675-01-22

March 1, 1675

Oldenburg wrote this letter when it was 19 February 1675 O.S. in London. It is known only by reference in other letters.

In this letter, Henry Oldenburg writes to Leeuwenhoek that his two most recent letters were well received at the Royal Society. He notes that knowledgeable people in Paris disagreed with Leeuwenhoek’s discovery of globules everywhere. Finally, he asks for better drawings of salt and suggests that the problem may lie in Leeuwenhoek’s microscope.


Recorded in both Alle de Brieven / Collected Letters vol. I, p. 229 and The Correspondence of Henry Oldenburg, vol. 11, p. 201.

At the bottom of Leeuwenhoek's Letter L-021 of 1675-01-22, Oldenburg wrote:

Answ. Febr. 19.167⅘. Kept no Copy.

Letter L-024 of 26 March 1675 to Henry Oldenburg:

Your esteemed letter of the 19th of February was received by me in good order, and I was very pleased to learn that my trifling observations set forth in my letters of January 22nd and of February 11th did not displease you nor the gentlemen amateurs, and I hope you will excuse my writing again.

You observe that people of great knowledge in Paris and elsewhere do not agree on the globules I have discovered in a great many bodies. I do not mind this at all. What I wrote on this subject is perfectly true, and if those learned gentlemen were living in the Netherlands, I should invite them to come and see the globules in most of the parts, as I described. I have the intention to write again about bodies composed of globules. ...

You told me (in your letter) that your friends wished the figures of the salt to be more neatly and distinctly drawn, and that possibly my microscope did not show the same more clearly. 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.