Wrote Letter 18 of 1676-10-09 (AB 26) to Henry Oldenburg

Date: 
October 9, 1676
Standard reference information
Cole's number: 
18
AB/CL number: 
26
AB/CL volume: 
2

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


Leeuwenhoek wrote this letter to Henry Oldenburg about microorganisms in various waters and spice infusions, the relationship of their shape to taste, and whether there were microorganisms in the air.

This is Leeuwenhoek's most famous letter, the one that made his name known world-wide. The bulk of Dobell's "Little Animals" is devoted to a translation and annotation of it.

The heart of the letter is 145 observations of 19 different series of liquids, about half of them infused with various spices.

Other than the observation from the previous September, they were all conducted from mid-April to the end of September, 1676. Some of the observations were one-time only. Many series lasted for a month or two. The longest spanned 18 weeks. A month later, Leeuwenhoek wrote to Constantijn Huygens (AB/CL 28), enclosing a copy of much of this letter of October 9:

I have couched my observations in the form of a journal, merely that they be better credited in England and elsewhere, the more so because the Secretary, Mr. Oldenburg, wrote to tell me some time ago that there actually are learned gentlemen in Paris and elsewhere who do not believe what I saw.

The letter was written in a hand other than his, probably from his notes. The observations are listed here in the order in which Leeuwenhoek discussed them in the letter.

Rain Water

observations infusion preparation start end duration
1 Rain 1 rain standing few days in tub Sept 15    
2 Rain 2 rain off slate roof in leaden gutters in glass May 26    
3 - 5 Rain 3   May 26 May 31 5 days
6 - 12 Rain 4   June 9 June 16 1 week
13 - 19 Rain 5   June 9 June 16 1 week
20, 21 Rain 6   June 17 June 26 9 days

What he saw in rain water.

 

River, Well, and Sea Water

observations infusion preparation start end duration
22 River       summer
23 Well   1675 1676 indeterminate
24 Well   July    
25 - 30 Sea   July 27 August 8 12 days

What he saw in these waters.

Pepper Water

observations infusion preparation start end duration
31 Pepper 1 3 oz whole pepper in snow water April 24   3 weeks
32 - 50 Pepper 2 ½ oz whole pepper in 2 ½ oz snow water in porcelain teacup April 26 June 1 5 weeks
51 - 60 Pepper 3 1/3 oz whole pepper pounded in teacup with 2 ½ oz rainwater, added water from Pepper 2 May 26 June 12 3 weeks
61 - 63 Pepper 4 certain quantity of whole pepper in well water June 14 July 20 5 weeks
64 - 93 Pepper 5 a quantity of coarsely ground pepper in well water that already had bacteria in it August 2 Sept 19 7 weeks

What he saw in pepper water.

 

Spiced Water

observations infusion preparation start end duration
94, 95 Vinegar   n.d.   2 weeks
96 - 106 Ginger bruised ginger pieces in snow water in tea cup May 6 June 12 5 weeks
107 - 127 Clove 36 cloves in 21 oz rain water with no animals May 17 Sept 19 18 weeks
128 - 145 Nutmeg pieces of beaten nutmegs in 2? oz well water with only a few extraordinay small creatures July 13 Sept 7 8 weeks

What he saw in spiced water.

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