Gottfried Leibniz wrote to Hendrik van Bleyswijk about encouraging Leeuwenhoek to train students

January 3, 1698

The date is New Style, which was ten days ahead of the Old Style date of 24 December 1697 used by Leibniz in Hanover.

In response to the letter of 7 November 1697 from Hendrik van Bleyswijk, Leibniz thought that Leeuwenhoek’s observations were so important that it was a matter of “Christian charity” for Leeuwenhoek to train others. To do otherwise would be “wrong”. Bleyswijk replied on 17 February 1698.



Allgemeiner Politischer und Historischer Briefwechsel (General political and historical correspondence), vol. 15, January-September 1698, no. 120:

As for Monsieur Leeuwenhoek, I admit that he has some reason to keep his way of observing a secret, which deserves to be honored. But if the public gives him encouragement to be in a position to be helped by pupils, it would be very wrong if he continued to be difficult; nothing could be more advantageous to him. Since by this means he will make ten observations for one, we will discover treasures of knowledge which perhaps without that would remain unknown for a long time and there will be all the more glory closing the mouths of a thousand contradictors: besides that, these kinds discoveries can even be used in medicine, and one day contribute to the relief of men. Thus, Christian charity enters into it and there will be merit in pushing them. For me who considers these works infinitely above those of a Raphael of Urbino, or of a Michelangelo, I would believe that Delft could make a point of honor in the republic of letters, and that this beautiful city however celebrated she may already be by her Delphic Oracle, that is to say by the incomparable Grotius, would receive a notable increase in her glory by contributing to a considerable elucidation of the secrets of nature.