Henry Oldenburg wrote to Leeuwenhoek in response to his letter of 1675-01-22

Date: 
February 19, 1675

At the bottom of Leeuwenhoek's Letter No. 15 [9] of 1675-01-22, Oldenburg wrote:

Answ. Febr. 19.167⅘. Kept no Copy.

Oldenburg wrote that letter when it was March 1 New Style in Holland.

Document: 

Recorded in both Alle de Brieven / Collected Letters vol. I, p. 229 and The Correspondence of Henry Oldenburg, vol. 11, p. 201

Sources