Edmond Halley wrote Letter L-170, known only by reference in Letter L-176

March 12, 1686

This letter is lost and is known only by reference in another letter.

The date is New Style, which was ten days ahead of the Old Style date of 2 March used by Halley in London.

In E.F. MacPike, Correspondence and Papers of Edmond Halley, Letter 13 by Halley is actually Letter L-170 of the same date by Thomas Gale to Leeuwenhoek, the manuscript of which is lost, but a copy of which is to be found in London, Royal Society, Letter Book Original 11A.16, p. 38. Leeuwenhoek quotes from it extensively and accurately in Letter L-173 of 2 April 1686, which begins, “I was exceedingly pleased to read, in your favour of the 2nd/12th March, written by Your Honours’ Secretary Mr. Thomas Gale.”

The confusion arose from the lack of the writer’s name on the copy and Halley’s statement to begin Letter L-176 of 25 May 1686, in this volume: “Since my last of the 2d of March.” There is no letter by Halley of that date in the Royal Society’s archives, nor is there any mention of such a letter in Leeuwenhoek’s letters.

It is also possible that the copy in the Letter Book Original was written by clerk Halley and signed by secretary Gale. When the Royal Society reorganized after the resignations of its two uncompensated secretaries, they listed the duties of their newly created position of paid clerk. The fourth duty was that “He shall draw up all letters, and bring them to be signed by one of the secretaries”. See Birch, The History of the Royal Society of London, vol. IV, p. 454, and Letter L-161 of sometime between 9 August and 22 October 1685.


Letter L-176 of 25 May 1686 from Edmond Halley

Since my last of the 2d of March, we have recieved your answer thereto, and lately another of the fourteenth courant.