The Royal Society asked Olderburg to produce Leeuwenhoek's Letter L-011 of 1 June 1674

November 22, 1674

Birch's History of the Royal Society of London, vol. III, p. 143, 12 November 1674 (O.S.) in London:

Mr. OLDENBURG was desired to produce Mr. LEEWENHOECK'S observations concerning air, blood, &c.

There is no further mention of this letter in Birch's History.