Royal Society read Letter L-572 about muscle fibers and iron
Date:
May 21, 1722
The date is New Style, which was eleven days ahead of the Old Style date of 10 May 1722 used in London.
Document:
Royal Society, Journal Book Original, vol. 13, p. 193-95. It includes a long, detailed summary of the letter and ends, “Mr. Leeuwenhoeck was ordered thanks”, which Jurin did in Letter L-575 of 26 May 1722 (dated 15 May 1722 O.S.).