John Somers wrote Letter L-395 of 15 November 1701 to Leeuwenhoek about the bequest of 26 magnifying glasses and accepting Leeuwenhoek's unverified observations as "matters of fact"

November 15, 1701

No manuscript is known. Never published. The date is New Style, which was eleven days ahead of the Old Style date of 4 November 1701 used by Royal Society president Somers in London.

In this letter, Somers thanked Leeuwenhoek for announcing that upon his death, he is bequeathing a cabinet with 26 of his microscopes to the Royal Society. He added that so many of L.’s observations have been verified that the Society now accepted Leeuwenhoek’s observations as “matters of fact”.

By the early 19th century, the cabinet and its microscopes were lost. See Ford, “What were the missing Leeuwenhoek microscopes really like?” and Robertson, “van Leeuwenhoek microscopes—where are they now?”

This letter was enclosed with the English Letter L-396 from Hans Sloane of 18 November 1701, Collected Letters, vol. 14, there unnumbered, untranslated, and dated 7 November 1701 O.S. Sloane wrote:

The Society are extreamely sensible of all your favours & more especially of this last of your intended legacy they desire their president my Lord Somers to return you their thanks for all your favours in a most particular manner which he has done by the enclosed letter. The society would not have troubled a person of his qualities had not they desired very heartily to show you the respect they bear you.

Sloane was secretary of the Royal Society from 1693 to 1713 and editor of Philosophical Transactions from 1695 to 1713, volumes 19 thorugh 28. During this time, he published excerpts from 64 letters by Leeuwenhoek, more than half of the total number of 114 letters published there.

Two decades after the present letter, Royal Society vice-president Martin Folkes made a similar comment about accepting Leeuwenhoek’s observations without verification in his account of Leeuwenhoek’s bequest in Philosophical Transactions, Letter L-599:

We have seen so many, and those of his [Leeuwenhoek’s] most surprizing discoveries, so perfectly confirmed, by great numbers of the most curious and judicious observers, that there can surely be no reason to distrust his accuracy in those others, which have not yet been so frequently or carefully examined.


The copy transcribed below is in London, Royal Society, Letter Book Original 13.59, p. 186, 1 page. 

Lond. 4 Nov. 1701


            Your obliging letter of the second of August last, having been read by Doctor Sloane to the Society on the 22d of Octob. (which was the first time of their meeting after it was received) they have commended me in their name to thank you for the very valuable legacy you are pleased to design for them, of those admirable microscopes, by which you have made discoveries of so many things of great importance for the promoting of natural knowledge.

            The Society does very affectionately and sincerely wish you may live long to make use of those glasses, as you have done hitherto, with great judgement and success; but when at last they shall come to be possessed of them, you may be assured they will preserve them with the upmost care, not only on account of their real worth, but out of respect to the memory of so deserving a member of their body, and as an evidence of your esteem and friendship for the Society.

            I am also commanded to give you their thanks for the many useful observations you have frequently communicated to them, which they always receive with great pleasure. Such of them as have been tried by any other of their members have been so exactly verified by * experiments, that the Society give an entire credit to your relations of matters of fact. They hope you will continue to transmit accounts of what farther progress you make in your searches into nature in the same kind manner you have been accustomed to do. They have directed me in their name to assure you of their friendship and esteem: and I desire your leave to subscribe myself


            Your most humble servant

Somers President