Wrote Letter 44 of 1685-01-23 (AB 83) to Members of the Royal Society

Date:

January 23, 1685

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AB/CL volume:

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-seven quarto pages, written and signed by Leeuwenhoek, is preserved at the Royal Society (MS. 1903. L 1. 74).

Leeuwenhoek's summary

From both editions of Sout-figuren and translated into Latin for all of the editions, some re-titled, of Anatomia Seu Interiora Rerum.

Ontdekkingen van Sout-figuren. Sout van Carduus Benedictus, Sout van Alsem, Aluyn, Salpeter, Vitriool de Cypris, of blaauw Vitriool, Liquor Tartari, Moscovische Pot-as, Campher, Sout of As uyt den Oven van een Canon of Geschut-gieterye, Sout of As van een Tin en Loot-oven, Sout in de Steen-kalk, Sout van de Schulp-kalk, Sout van Engelse Soude, Sout van Brittanische Souda, Sout van de Alicante Souda, Sal armoniac.

Discoveries of Salt-Salt of Carduus Benedictus, salt of wormwood, alum, salpeter, vitriol de Cypris, or blue vitriool, liquor tartari, Moscovite potash, camphor, salt of ash from the oven of a cannon or gun foundry, salt of ash from a tin and lead oven, salt in limestone, salt of shell lime, salt of English soda, salt of Britannic soda, salt of Alicante soda, sal amoniac.

Reception in London

Over two months after Leeuwenhoek wrote this letter, it was read at the regular weekly meeting of the Royal Society on March 25 / April 4 (O.S./N.S. Birch's History, vol. IV p. 383, 397):

Part of a letter of Mr. Leeuwenhoeck to the Society, dated at Delft, January 23, 1684/5 was read, concerning the figures of the salt of carduus benedictus, of the salt of wormwood, of alum, salt-petre, and vitriol of Cyprus.

As he had for other recent letters from Leeuwenhoek, Martin Lister had a comment:

Dr. Lister remarked, that there were figures of common salt and alum among the salts of wormwood and some others; and that it was to be wished, that Mr. Leeuwenhoeck had prepared all his salts himself. He queried whether Mr. Leeuwenhoeck had ever seen salt of nitre finished at both ends, and how many sides it had; and he desired that Mr. Leeuwenhoeck would describe a large cryatal of vitriol.

Mr. Aston was desired to take: instructions from Dr. Lister, when he shall next write to Mr. Leeuwenhoeck.

Martin Lister seemed to have a special interest in Leeuwenhoek's work. His concern about Leeuwenhoek preparing his salts himself came from his understanding, probably from experience, that few substances purchased commercially were chemically pure. Leeuwenhoek may well not have undestood this. He had a mechanic's mind, not a chemist's.

It took another month, until May 6/16 for the members to find time for the rest of the letter.

There was read the latter part of Mr. Leeuwenhoeck's letter of January 23, 1684/5, being observations of the figures of the salts contained in the ashes sticking near the mouth of an oven of a foundery of cannon; in the ashes sticking to the sides of an oven, where lead is calcined; in the salts of quick lime; in the lime of sea-shells; in the English soda or glass-wort; in the soda of Britany; in the soda bariglia of Alicant: and in sal armoniac. The figures were likewise shewn, curiously designed by Mr. Leeuwenhoeck.

In the postscript he mentioned, that he had found in the womb of a bitch, that had been limed three or four times not three days before, a great number of living animals, which are the seed of a dog.

Leeuwenhoek had ended the previous Letter 43 of January 5:

It had been my intention to append my notes on observations of various salts, but, fearing lest I should overburden your Honors with too many of my writings at a time, I shall break off.

Less than three weeks later, he picked up where he had left off in this Letter 44 of January 23:

I now send you some of my observations concerning the salts mentioned in my last letter which, I hope, will be agreeable to your Worships.

In none of these letters to the Royal Society did Leeuwenhoek mention that he had begun publishing his letters in Dutch and Latin with booksellers in Leiden. [Note on Period 2 page.]

Specimens and methods

"Out of reach of the flame of the fire, I took some black material like smoke."

Leeuwenhoek often worked by comparing structures and processes in a variety of related specimens. For the observations reported in this letter, he gathered his specimens from shops around Delft.

An apothecary, perhaps the passage that triggered Lister's concern:

Some time after this I discussed the making of salt of Carduus benedictus with an apothecary, who told me that the salt most of his colleagues sell as Sal Cardui benedicti was nothing but a mishmash of the burned stalks of various herbs, and that he had now freshly made, genuine Sal Cardui benedicti.

A chemist:

I have examined the salt of wormwood, as kept in bottles by the chemist.

Delft had only one armament factory:

On and above the iron doors at the mouth of the furnace in which cannons are cast, there is a white, ash-like substance which is formed there from the matter ejected from the furnace by the copper, the tin and the flame of the wood and there adheres or collects. I took some of this ash.

A Delftware factory:

Our potters use much tin and lead which they burn, in furnaces, to ashes. This process of burning, which they sometimes continue for ten to twelve days on end, so as to lay up a stock that will last them a long time, and avoid having to spend two or three days at it every month, is so injurious to the health of those engaged on the work that they are overcome after no more than 24 hours' attendance at the furnace, and then look as though they had been poisoned.

This means that a different man has to be put every day on the job of watching the furnaces and continually skimming off the ashes which accumulate on the surface of the molten lead and tin, and scooping it out of the furnace. This led me to collect the ash-like substance on the bricks close to the mouth of the furnace, licked by the flame which constantly spurts through the mouth of the furnace, and to put it in water and examine the latter when it had become clear.

From the chimney of the tin- and lead-furnace, about two feet from its mouth, out of reach of the flame of the fire, I next took some black material like smoke.

A soap factory:

I went to visit two soap boilers so that I might understand what use or purpose the potashes and soda serve in soap-making. They told me that it was impossible to make solid or thick soap from the strength or salt of potash or soda alone, but that it was necessary to mix lime-water with it and that only the latter solidifies or stiffens the soap. They also told me that the water or salt of lime burned from stone is best for the purpose, though they did not know why.

From the observations I have reported, however, we may well find reasons why.

Preview of the upcoming letter

In the previous Letter 43, Leeuwenhoek had written:

P.S. After concluding this, I opened a bitch, or female dog, and found in its womb, or let it rather be said in both tubes, a large quantity of the male seed of a dog, of which I shall treat further on a future occasion.

In this Letter 44, he wrote:

A few days ago I again acquired a bitch on heat which, I was told, had mated three or four times three days previously. I killed it and examined the womb, which was reasonably wide, and there found everywhere an enormous number of living animalcules, the male seed of the dog. I shall pursue these observations of mine and send you my notes thereon at a future date.

The public and their opinions

"A given remedy does not have precisely the same effect upon all cases of the same disease"

In the middle of his account of his visits to Delft shopkeepers to collect samples, he noted a conversation that he had with a doctor:

Some years ago a certain doctor told me in the course of conversation that, in the application of his remedies, he had been astonished to find that, whereas a medicine he had used after careful forethought for some disease would be entirely successful at one time, at another it would be wholly without effect upon the same disease.

I thereupon suggested to him that, ... if we consider the difference in the body-temperature as between one person and another and, besides, that some salts are liable to become more rigid in increased heat, we shall not be so surprised to find that a given remedy does not have precisely the same effect upon all cases of the same disease.

Figures

The orginal drawings are lost. Similarly to the previous Letter 43, the way Leeuwenhoek discussed the figures in the text indicates that he saw them as 87 figures on 17 numbered plates. Here and in Alle de Brieven / Collected Letters, they are treated as 17 figures placed near the text where Leeuwenhoek discussed them.

In the text, Leeuwenhoek did not say who made the two and three-dimensional drawings of the crystals of various salts. They were well within his skills, so he probably drew them himself in red chalk. The scans on the sidebars came from the 1708 third edition of Arcana Naturae Microscopiorum.

Publication history

Related sources, especially Philosophical Transactions, and first editions only of Leeuwenhoek's volumes of letters. For later editions see Related events under Learn more.

Year	Author	Title
1665	various	Philosophical Transactions
1685	Leeuwenhoek, A. van	An Abstract of a Letter from Mr. Leewenhoeck, to the R. S. Dated Jan. 23d, 1684/5; Concerning the Various Figures of the Salts Contained in Several Substances
1685	Leeuwenhoek, A. van	Sout-figuren
1687	Leeuwenhoek, A. van	Anatomia Seu Interiora Rerum
1957	Leeuwenhoek, A. van	Alle de Brieven. The Collected Letters. Volume 5

Other publications:

On July 22, 1685, an extract of this letter was published in Philosophical Transactions, vol. 15 no. 173. Unlike most of the other letters during these years, it was not published elsewhere.

Notes

The compound sout-figuren seems to appear in only Leeuwenhoek's writing. Figuur is in neither Hexham's 1675 dictionary nor Sewel's 1735 dictionary. The Middelnederlandsch Woordenboek calls it an obsolete term for "shape" or "form". In the text of the letter, Leeuwenhoek uses the Dutch word cristal to refer to the shapes he saw, some of them forming while he watched.

Learn more

Period 2 - 1679-1686

Structure of the letters in Period 2

1685: Being ignorant of all other men's thoughts

Related people:

Members of the Royal Society

Related events:

Date	Event
January 1, 1685	Published Sout-figuren (Salt figures), Letters 44, 45
April 4, 1685	The Royal Society read the former part of Letter 44 of 1685-01-23 about salts in wormwood, alum, and other substances
May 9, 1685	The Royal Society read part of Letter 44 of 1685-01-23 about oil of tartar, potash, and camphor
May 16, 1685	The Royal Society read the latter part of Letter 44 of 1685-01-23 about salts in ashes, lime, soda, and sal armoniac
May 28, 1685	The Dublin Philosophical Society asked the Royal Society for a copy of Letter 44 of 1685-01-23 on salts of wine and vinegar
January 1, 1687	Published Anatomia Seu Interiora Rerum (Interior Anatomy), 19 Letters from 28 - 52
January 1, 1696	Published Arcana Naturae Microscopiorum (Nature's Mcroscopical Mysteries), 19 Letters from 28 - 52 (2nd)
January 1, 1696	Published Sout-figuren (Salt figures), Letters 44, 45 (2nd)
January 1, 1708	Published Arcana Naturae Microscopiorum (Nature's Mcroscopical Mysteries), 19 Letters from 28 - 52 (3rd)
January 1, 1722	Published Opera Omnia, seu Arcana Naturae Microscopiorum (The Works, or Nature's Microscopical Mysteries), 25 Letters from 28 - 60 (4th)

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Letter 44 Figures 1-10

Wrote Letter 44 of 1685-01-23 (AB 83) to Members of the Royal Society

"Out of reach of the flame of the fire, I took some black material like smoke."

"A given remedy does not have precisely the same effect upon all cases of the same disease"

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Letter 44 Figures 11-17