The Royal Society read the second part of Leeuwenhoek's long letter of 9 October 1676
According to Birch's History, vol. 3, p. 333, at their weekly meeting on 8 February 8 1677 (18 February in Delft), the Royal Society read the second part of Leeuwenhoek's long Letter L-040 of 9 October 1676.
Mr. Oldenburg produced the sequel of Mr. Leewenhoeck's letter concerning the great plenty of very little animals observed in rain, well, sea, and snowwater; as also in water, in which pepper had lain infused.
The remainder of this paper was referred to another meeting; and the secretary was again desired to procure from Mr. Leewenhoeck his method of observing, that by making use of the same, the Society might be enabled to confirm his observations.
Oldenburg wrote that request to Leeuwenhoek four days later, on February 12/22.