Visited by Sir Francis Child

June 1, 1697

From May to September of 1697, the negotations to end the Nine Years' War took place in the Dutch Republic. The French negotiating team had their headquarters in Den Haag. The team for the Allies -- England, Spain, the Holy Roman Empire, and the United Provinces -- had theirs in Delft. The negotiations took place halfway between them in Rijswijk.

During that summer, Sir Francis Child, an English banker and politician, toured the area, which he recorded in the unpublished "A journal of my travels through the United Provinces."

He devoted a short passage to his visit to Leeuwenhoek's house. First, he noted that Leeuwenhoek was "a fellow of our Royal Society". Through a microscope that magnified objects “one million times”, he saw “the testicles and eggs of lice, the eggs of oysters and several other dissections of the most minute insects”. He recommended reading of Arcana naturae detecta, Leeuwenhoek's recently published volume of letters translated into Latin.

On September 10 of that year, Leeuwenhoek sent Letter 110 (AB 188) to the Royal Society. In it, he wrote about oysters, perhaps the ones he showed Child.