Robert Hooke wrote Letter L-118 to Leeuwenhoek that his observations of shellfish muscles were well received by the Royal Society and concurred with his own

March 26, 1682

This letter was transcribed by Delft archivist Petra Beydals in the 1930s and was found in the handwritten papers she left in the archives, Stadsarchief Delft, archive no. 479 Collectie P. Beydals, inv. 58. The signed autograph is to be found in London, Sloane MS 1039, f. 134; 1 quarto page.

Beydals's notes date it as 16 March in London, which was 26 March in Delft.

Hooke’s previous letter to Leeuwenhoek is Letter L-117 of 20 March 1682, to which Leeuwenhoek did not reply before receiving the present letter. Leeuwenhoek replied with his final two letters to Hooke, Letter L-119 of 4 April 1682 and Letter L-120 of 28 July 1682, to which Hooke did not reply before he was replaced as Royal Society secretary on 30 November 1682 by Robert Plot. The duty to correspond with Leeuwenhoek passed to the other secretary, Francis Aston because Plot became editor of Philosophical Transactions for volumes 13 and 14 in 1683 and 1684. He published six letters by Leeuwenhoek.

Hooke’s next and final letter to Leeuwenhoekuwenhoek, sixteen years later, is Letter L-345 of 9 June 1698.


Worthy Sr.

I have received your most ingenious and obleiging letter of this present month and immediatly translated it into English, and read it to the Royal Society at their first meeting who were exedingly pleased therewith and desired me to returne yow theire heartly thanks and they doe earnestly desire yow to continue these yor curious observations and wish yow a continuance of good success in yor discoveries wch have bin hitherto very considerable and instructive. And as a mark of theire respects to yow and of theirs esteeme of yor discoverys they desired yt they should be forthwth fitted for the press and published yt ye whole world might participate of the benefit, the like sentiments and proceedings they had upon my excommunicating to them yor former letter of Novembr last, wch I signified unto yow soone after, but wonder much yow have not read it. I have since published by their ordr two of yor letters in the collecting wch come out every month wch I have taken care to convoy to yow as I shall doe the rest soo fast as they come forth.

I have not exactly followed yor letter word for word in the translaton, but as neare as possibly I could I have expressed the true sense of yor expressions, and the draughts are copied as neere as I could gett them done, yor discoveries in this last I am very well pleased wth all for yt they doe very well concurr wth severall observacons, I made divers yeares since and shewed them to the Society in the stringy parts of the muscles of crabbs, lobsters and prawnes, of which about 4 yeares since, I gave yow some adverisements wt I then shewed to ye Societie was yt ye body of the muscles of these creatures was made up of avery great number of exceeding small filaments or strings, almost 100 tymes smaller then a haire of ones head, each of wch appeared like a necklace of pearls and the bulk of yt muscle like a necklace of small seed pearle composed of many of those strings, though I was not soe happy as to discover the like in the stringly parts of the muscles of flesh. yow have advanced yor discoveryes very much further in that yow have not only discovered such knotts or folds, but even the parts or texture of those filaments and soe have probably discovered ye very reason of such folding and thereby of yt hitherto unknowne phonomeno the contractions and motion of muscles.

Goe on Sr wth these yor most excellent inquirus and that yow may be happy and succesfull in making further and further discoverys into yor arcana and mysterys of the hitherto invissible and unknowne parts of the world is the hearty wish as of ye Royal Society soe alsoe of worthy Sr yor

most Humble servant
Secretary (Royal Society)
R. Hooke