mentor Dr. Cornelis 's Gravesande appointed to Veertigraad

September 10, 1672

As part of the wetsverzetting of 1672, the new Stadthouder, Willem III, replaced half of the Delft Veertigraad (Council of Forty) with pro-Orangist members, including Leeuwenhoek's friend Cornelis 's Gravesande.

's Gravesande took this opportunity to made extensive notes of the proceedings of the meetings. These notes have survived and are collected in the archives as Aantekeningen van de vergaderingen van de Veertigraad (Notes of the meetings of the Council of Forty).