Wrote Letter 43 of 1685-01-05 (AB 82) to Members of the Royal Society

January 5, 1685
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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 twenty-one quarto pages, written and signed by Leeuwenhoek, is preserved at the Royal Society (MS. 1902. L 1. 73).


The original drawings are lost. The way Leeuwenhoek discussed them in the text, he saw them as 76 figures on 11 numbered plates. Here and in Alle de Brieven / Collected Letters, they are treated as 11 figures placed near the text where Leeuwenhoek discussed them. The scans on the sidebars came from Opera Omnia, the fourth edition of Arcana Naturae Microscopiorum.

In the text, Leeuwenhoek did not say who drew Nos. 2, 6, 8, 10, and 11. He noted that he drew Nos. 3, 4, 7, and 9. Of them, No. 4 involved the greatest artistic skill. Leeuwenhoek wrote of those figures specifically:

I shall draw these larger than I actually see them, the better to show how they are formed.

He wrote about No. 9:

There were also several oblong four-sided salt-particles which were likewise very thin and transparent, also very minute, though drawn fairly large in fig. H, the reason being that I was unable to draw them to the same scale, because the microscope with which I could see the figures represented by A, B, C, D, E and G very distinctly was not powerful enough to reveal those represented by F and H.

He had at least part of No. 1 and Nos. 2 and 5 drawn for him. On No. 1, the upper two rows, Figs. A through F, look as though they were drawn by someone with less skill than the four figures on the lower two rows. Leeuwenhoek did not say who drew the upper figures; it may well have been himself. Of the lower figures, he wrote:

I had a drawing made of several of these, with the excavation in full view as in fig. G; also some seen partly from aside, and showing. part of the excavation as in fig. H. I also had a full-grown living eel, among the many present in this vinegar, drawn as will be seen in fig LM; likewise a full-grown specimen which I had killed so that the draughtsman should see it more distinctly (see fig. NO).

He had two reasons to show that figure.

My object being to illustrate the minuteness of the salt particles in the vinegar by comparison with the size of the little eels (though it should be borne in mind that both the particles and the eels were drawn from a view of them through an ordinary microscope, whereas I have detected very much smaller particles of salt in the vinegar which were invisible through the said microscope).

Another reason was that many people firmly imagine that the perception of the acidity of vinegar is due to the fact that the eels thrust their sharp tails into our tongues, in which they are in error.

He wrote about No. 5:

Of these I first made a rough sketch and then showed them, through a microscope, to a good draughtsman (goet Teekenaar), whose drawing of them is given here as No. 5, fig. A.