Traveled to England
Date:
January 1, 1668
Some time during this year, he traveled to England and used a lens to examine the chalk deposits to learn why they are white as well as the clay used in porcelain.
Leeuwenhoek wrote in Letter 6 of September 7, 1674: "Ontrent ses jaer geleden uijt curiusiteit in Engelant sijnde, ende tot Gravesant, Rochester, etc. siende de groote Krijtbergen, ende Krijtachtige landen."
The "ontrent" could make it anywhere from mid-1667 when the Peace of Breda made civilian Channel traffic safer to February 1669 when Leeuwenhoek was certified as a surveyor. Given the weather, fall 1667 and summer 1668 are the most likely.
Document:
Letter 6 of September 7, 1674: “About six years ago, being in England”
