Hans Sloane wrote Letter L-500 to Leeuwenhoek about responses to his recent letters

October 24, 1713

Never published.

The date is New Style, which was eleven days ahead of the Old Style date of 13 October 1713 used by Sloane in London.

According to a note in the Royal Society’s Early Letters, this letter by Sloane was read at the meeting of the Royal Society on 22 October 1713 O.S.

A copy of the letter is to be found in London, Royal Society, Letter Book Original 15.14, pp. 22-23.

This is Sloane’s final letter to Leeuwenhoek. On 30 November 1713, he was replaced as second secretary and Philosophical Transactions editor by Edmond Halley, who neither corresponded with L. nor published any of his letters. Instead, first secretary Richard Waller wrote the next letter from the Royal Society to Leeuwenhoek, Letter L-502 of 3 March 1714 and four others later that year, but he died that winter. Communication with Leeuwenhoek ceased until James Jurin was elected to replace Halley on 30 November 1721 and wrote his first letter to Leeuwenhoek on 5 March 1722, Letter L-571.


In this letter, Sloane was responding specifically to Leeuwenhoek's Letter L-496 of 1713-06-28. He acknowledges the receipt of that letter, reassuring Leeuwenhoek that the Society appreciates his correspondence. He believes that Philosophical Transactions were sent to him.

At the end of that letter, Leeuwenhoek had mentioned a letter that he sent to Antony Heinsius the previous November 8, 1712. So four months after that, Sloane finally asked Leeuwenhoek to send the Heinsius letter. Leeuwenhoek did so immediately, and the letter to Heinsius was published in early 1714 in the second number of volume XXIX of Philosophical Transactions. There, it was dated 1713-10-12, the day Leeuwenhoek sent it to Sloane with a cover letter, not 1712-10-08, the date it was actually written. Leeuwenhoek published that letter, with the November 1712 date, in 1718 as Letter I in Send-Brieven.

The dates for this exchange of letters seem impossible. Below is the order they had to have been written in. Note that the third one, the only letter from Sloane to Leeuwenhoek on this list, is out of chronological order.

L-489 1712-11-08 N.S.

letter from AvL to Heinsius (SB I AB 296) -- published in Philosophical Transactions v. 29 no. 339 and in Send-Brieven 1718

L-496 1713-06-28 N.S. | 1713-06-17 O.S.

letter from AvL to Sloane (SB VII AB 302) -- published in Philosophical Transactions v. 28 no. 337 and in Send-Brieven 1718 -- asking whether Royal Society wanted to see letter to Heinsius

L-500 1713-10-24 N.S. | 1713-10-13 O.S.

letter from Sloane to AvL -- unpublished -- asking to see letter to Heinsius -- this letter had to have arrived before AvL sent the letters he dated 1713-10-12 N.S.

L-499 1713-10-12 N.S. | 1713-10-01 O.S.

letter from AvL to Sloane (AB 304) -- unpublished at the time -- cover letter thanking Sloane for his letter of 1713-10-20 O.S. (1713-10-31 N.S.) and enclosing Letter L-489 of 1712-11-08 from AvL to Heinsius -- published in Philosophical Transactions v. 29 no. 339 with date of 1713-10-12 -- saying ...

1714-01-12 N.S. | 1714-01-01 O.S.

Philosophical Transactions v. 29's official publication date, actually closer to the day the first number was published, no. 338. The following no. 339 with Leeuwenhoek's letter was probably in print by mid-Spring. Leeuwenhoek's article about muscles in whales as well as in other fish, oxen, and mice was immediately followed not by a letter, but by a summary. An unnamed writer summarized an article by Wyger Willem Muys reporting his finding that blood left the blood vessels and spread through the hollow muscle fibers. Muys noted that his findings were contrary to Leeuwenhoek's.

If the letters are arranged in chronological order, then on October 12 in Delft, October 1 in London, Leeuwenhoek wrote a reply to a letter that Sloane hadn't written yet; this reply referred to a letter by Sloane that Leeuwenhoek gives one date for -- October 20 in London, October 31 in Delft -- but the Royal Society's Letter Book gives a different date for -- October 13 in London, October 24 in Delft.


from Early Letters S2.17, p. 22-23

A Letter from Dr. Sloane to Mr. Leewenhoek in answer to his last of the 28th of June.

Oct. 13, 1713


     Your Letter to the Royal Society dated the 28th of June last came soon after to their hands and was delivered to Mr. Chamberlayne of whome the Society desired the favour to translate it into English. He sent it to me a few dayes since and shall lay it before the Society some time hence when they shall begin to meet. I would not have troubled you with this till I had received the commands of the Society had not I observed by yours that you have not received the thanks of the Society for four of your former Letters whereas they have ordered you their thanks every time you have sent them your observations which will appear by the minutes of the Assemblies in which they were read and I do assure you I have not only received such directions but wrote to you such Letters as directed; Mr. Hunt was also commanded by the Society to send you the last years Transactions which I am very confident I remember he did by some person going to Holland, who desired to carry them to you. Tis very likely some of the Letters and this parcell of Tranactions have not been delivered. If you have not yet received them let me know what numbers you have and I will supply you with these already printed & that are now printing, and because Mr. Hunt who knew how to direct to you such parcells is dead tell me how to send to you. Please also to send a copy of your Letter to the Heer Antonij Heinsius & it as also your other Letters will be gratefull to the Society &

Your most obedient servant
Hans Sloane