Wrote Letter L-110 of 1680-09-28 to Thomas Gale to inquire whether Letter 107 of 1680-06-14 had arrived

Text of the letter in the original Dutch and in English translation from Alle de Brieven. The Collected Letters at the DBNL - De Digitale Bibliotheek voor de Nederlandse Letteren

The original manuscript on one quarto pages, written and signed by Leeuwenhoek, is preserved at the Royal Society (MS. 1890. Early Letters L1.61).

Six weeks after his previous letter to Robert Hooke, Leeuwenhoek had still not received a response. He wrote this letter to Gale expressing his concern. He referred to Hooke's last letter of April 12, five months previously. Again, he noted that he had new observations.

In the last letter which I received from your colleague Mr. Robert Hooke, this gentleman assures me that any letter I shall write to him will certainly be answered by you. Now, having sent to the said gentleman some observations on the 14th of June and having up to now received no reply to my request of the 9th of August for acknowledgment of that missive, I cannot but think that my letters are lost. For which reason I take the liberty to address this letter to you, earnestly requesting you kindly to let me know if my above-mentioned letter of the 14th of June has come to hand, in which case I will forward to you a continuation, which I have already committed to paper, as well as several new discoveries.

Leeuwenhoek did not remember correctly. Letter L-107 to Hooke was the cover letter. It was Letter L-108 of the same date, 14 June 1680, to Gale that had the observations.

Birch's History has no record that the members of the Royal Society noted this letter at a meeting.