Visited neice Rijcke van Leeuwen in Rotterdam
September 3 was also the date of Letter 109 of 1697-09-03 (AB 187) to Jan van Leeuwen. It is unclear whether this Jan was Rijcke's husband or her brother. Given that he wrote the letter while staying at Rijcke's house, he probably addressed it to her husband. If it were to her brother, it could have been because brother Jan forwarded to Delft the packets of Philosophical Transactions sent from London.
In Letter 110 of 1697-09-10 (AB 188) to Members of the Royal Society, Leeuwenhoek wrote:
Further, being at Rotterdam on the third of September and arriving about noon at the house of a relative of mine, I was treated to English Oysters which had come from Zeeland that very morning, of which Oysters I ate about 25.