Lens on Leeuwenhoek

Chronology of events: 1673--1692

For some events, the year is certain but the month and day are not. Example: We know only the year for the collections of Leeuwenhoek's letters published in Dutch during his lifetime.

For other events, the season or month are certain but the day is not. Example: Leeuwenhoek mentions that someone visited him "last month".

On the other hand, many events did indeed happen on the first day of a month. Example: public appointments to Delft's city offices took effect on January 1 of each year. Thus:

A date of January 1 in a given year may indicate that the year is certain but the month and day are not.
A date of 1 in a given month may indicate that the year and month are certain but the day is not.

Unless otherwise indicated, for events in England, the date given is Old Style, 10 days behind the Dutch Republic's New Style until 1700 and then 11 days behind.

Date
May 24, 1684	The Royal Society read the first part of Letter L-147 about the crystalline humour of the eye
May 26, 1684	William Molyneux demonstrated blood flow in a newt to the Dublin Philosophical Society
May 31, 1684	The Royal Society discussed Leeuwenhoek's observations in Letter L-147 about the crystalline humour of the eye
June 7, 1684	Francis Aston wrote Letter L-148 to Leeuwenhoek to thank him for his letter with observations of the lens of the eye, which was read to the Royal Society and was well-received by them
June 14, 1684	The Royal Society read the latter part of Letter L-147 about the crystalline humour of bird and fish eyes, the vitreous humour, the cornea tunica, and the colour of a Blackamore
June 15, 1684	Visited Christiaan Huygens in Den Haag with the Durven brothers
July 24, 1684	Daniel van Gaesbeeck wrote Letter L-149 about why he is publishing more of Leeuwenhoek's “mutilated”, “mistranslated”, and “misunderstood” letters
July 25, 1684	Wrote Letter L-150 of 1684-07-25 to Members of the Royal Society about parts of the brain of several animals, chalk stones of gout, leprosy, and the scales of eels
July 27, 1684	Christiaan Huygens gossiped about Maria Duyst in a letter to his brother Constantijn Huygens
September 15, 1684	Francis Aston wrote Letter L-151 to Leeuwenhoek that Letter L-150 had not been read by the Royal Society
December 13, 1684	sister Catharina Philips Leeuwenhoek received legacy from great uncle Johan Sebastiaans van den Berch
December 13, 1684	The Royal Society read the first part of Letter L-150 about the brain of several animals, chalk stones of gout, leprosy, and scales of eels
December 20, 1684	cousin Geertruijt Huijchs Leeuwenhoek buried
January 1, 1685	cousin Maerten Huijchs Leeuwenhoek appointed tax farmer
January 1, 1685	Published Anatomia et Contemplatio (Anatomy and Contemplation), Letters 43, 42, 38 (L-128, L-150, L-152)
January 1, 1685	Published Onsigtbare Verborgentheden (Invisible Mysteries), Letters 38, 42, 43 (L-152, L-150, L-128)
January 1, 1685	Published Sout-figuren (Salt figures), Letters 44, 45 (L-154, L-157)
January 1, 1685	Published Zaden van Boomen (Seeds of Trees), Letters 46, 47 (L-160, L-166)
January 5, 1685	Wrote Letter L-152 of 1685-01-05 to Members of the Royal Society about salts in wine and vinegar and in the stomach, the eye, the need for food and water, Descartes's theory on smallest water particles, and a theory of taste - salt, sour and sweet
January 17, 1685	The Royal Society read the latter part of Letter L-150 about the brain of an ox and a sparrow, moxa, chalk from gout, leprosy, and eels, in which he discovered both scales and fins
January 20, 1685	Francis Aston wrote Letter L-153 to inform Leeuwenhoek that his recent letter about wine was favorably received at the Royal Society
January 23, 1685	Wrote Letter L-154 of 1685-01-23 to Members of the Royal Society about salts and their crystals and his theory about the causes of taste
January 31, 1685	The Royal Society read the former part of Letter L-152 about salts in vinegar and wine, vinegar eels, and salts found in vinegar mixed with crabs eyes and chalk
February 5, 1685	Visited by Thomas Molyneux on behalf of the Royal Society
February 7, 1685	The Royal Society read and discussed the latter part of Letter L-152 salt in various wines, mixtures of tartar, crabs eyes, or chalk with wine, and the difference between salts in wines and salts in chalk stones of gout
February 13, 1685	Thomas Molyneaux wrote Letter L-155 of 1685-02-13 to Francis Aston about his visit to Leeuwenhoek's house
February 19, 1685	Francis Aston wrote Letter L-156 to inform Leeuwenhoek that his Letter L-154 about salts was received but had not been read to the Society
February 23, 1685	At age 52, his 25th article in Philosophical Transactions
March 30, 1685	Wrote Letter L-157 of 1685-03-30 to Members of the Royal Society about sperm, the uterus of a bitch, sheep embryos, ovaries in young animals and apples, and his claims that sperm are the life-carriers and that there are male and female sperm
April 4, 1685	The Royal Society read the former part of Letter L-154 about salts in wormwood, alum, and other substances
April 20, 1685	At age 52, his 25th letter in Philosophical Transactions
May 9, 1685	The Royal Society read part of Letter L-154 about oil of tartar, potash, and camphor
May 16, 1685	The Royal Society read the latter part of Letter L-154 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 L-154 about salts of wine and vinegar
May 31, 1685	Maria Duyst van Voorhout married Frederik Adriaan van Reede van Renswoude
June 20, 1685	The Royal Society read part of Letter L-157 about the role of eggs and male sperm in a female dog
June 22, 1685	Visited by John Locke
June 27, 1685	Francis Aston wrote Letter L-158 of 1685-06-27 to pass along the recommendation by John Hoskyns that Leeuwenhoek examine silkworm eggs
June 27, 1685	The Royal Society read the latter part of Letter L-157 about sperm and eggs in sheep and rabbits
July 2, 1685	sister Catharina Leeuwenhoek appointed as tax collector for three years
July 11, 1685	cousin Adriaen Lambrechts Leeuwenhoek appointed curator
July 13, 1685	Wrote Letter L-159 of 1685-07-13 to members of the Royal Society about reproduction of trees, transfer of nutrients, male and female trees, hazelnut, comparing reproduction of mammals with reproduction of plants, cross-breeding, and germination
July 22, 1685	Royal Society published Letter L-154, titled, “An abstract of a letter from Mr. Leewenheock, to the R. S. Dated Jan. 23rd, 1685; concerning the various figures of the salts contained in several substances”
August 3, 1685	Anthonie Heinsius wrote Letter L-160 to Leeuwenhoek about Robert Boyle's reaction to the letter about cochineal
August 9, 1685	Francis Aston wrote Letter L-161 of some time between August and October 1685 to inform Leeuwenhoek that Letter L-159 had been received but not yet read
August 10, 1685	Wrote Letter L-162 of 1685-08-10 to Anthonie Heinsius about cochineal
August 27, 1685	editor Edmond Halley did not publish any letters by Leeuwenhoek in Philosophical Transactions from 1685 to 1693
August 31, 1685	Anthonie Heinsius wrote Letter L-163 of 1685-08-31 about Boyle's idea about the origin of cochineal
September 21, 1685	Wrote Letter L-164 of 1685-09-21 to Anthonie Heinsius about cochineal
October 1, 1685	Visited by Karl von Hessen-Kassel and Willem Meester sometime in October
October 2, 1685	Karel von Hessen-Kassel wrote Letter L-165 to thank Leeuwenhoek for the visit to his house
October 12, 1685	Wrote Letter L-166 of 1685-10-12 to members of the Royal Society about the beginning of plants in seeds; chyle, sweat, about skin, optic nerve, and bile of fish; salts in beer vinegar and lemon juice; and spirits mixed with blood and wine vinegar
November 5, 1685	Constantijn Huygens Jr. wrote to his brother Christiaan about Leeuwenhoek's character and the visit by Hessen-Kassel and Meester
November 14, 1685	The Royal Society read and discussed Letter L-159 about reproduction of trees, comparison of reproduction of mammals with the reproduction of plants, and cross-breeding
December 1, 1685	Visited by De Saingermain, who later called Leeuwenhoek a "Magus"
December 17, 1685	Constantijn Huygens wrote Letter L-167 to Leeuwenhoek about root trees
December 19, 1685	Francis Aston and Tancred Robinson abruptly resigned as the secretaries of the Royal Society, just a week after they had been reelected
December 25, 1685	cousin Elisabeth Maertens Leeuwenhoek married Dirck van Schie
January 1, 1686	Published Cinnaber Naturalis (Natural Cinnabar), Letters 48 - 52
January 1, 1686	Published Levende Dierkens (Living Animals), Letters 28 - 31, 34 - 36
January 1, 1686	Sat for his oil portrait by artist Johannes Verkolje (1650-1693)
January 22, 1686	Wrote Letter L-168 of 1686-01-22 to members of the Royal Society about cinnabar naturalis, gunpowder, saltpeter, and air made by gunpowder and crab's eyes
January 23, 1686	The Royal Society read part of Letter L-166 about embryo plants in cotton seeds
February 6, 1686	The Royal Society elected Edmond Halley as clerk
March 12, 1686	Edmond Halley wrote Letter L-170, known only by reference in Letter L-176
March 12, 1686	Thomas Gale wrote Letter L-169 to Leeuwenhoek reviewing his recent "ingenious and curious communications"
March 13, 1686	The Royal Society read part of Letter L-166 about chyle, sweat, pores of the skin, the crystalline humour of the eye, and the optic nerve
March 15, 1686	A Prussian doctor wrote Letter L-171 of sometime after 1686-03-15 to request a visit, enclosing pieces of amber
March 16, 1686	Antonio Magliabechi wrote Letter L-172 to Leeuwenhoek, a "most courteous and agreeable letter"
March 20, 1686	The Royal Society read part of Letter L-166 about gall and the scales and slime of fish
March 27, 1686	The Royal Society ordered that the unread part of Letter L-166 be read at the next meeting
April 2, 1686	Wrote Letter L-173 of 1686-04-02 to members of the Royal Society about the structure of bone, the bark of trees, skin and scales, the moisture evaporating from his body, and a little peeling piece of skin
April 3, 1686	The Royal Society asked Francis Lodwick to translate Letter L-168 about cinnebar and gunpowder
April 10, 1686	The Royal Society read and discussed Letter L-168 about cinnebar and gunpowder
April 14, 1686	Wrote letter L-174 of 1686-04-14 to Antonio Magliabechi, now lost
April 24, 1686	The Royal Society ordered that Letter L-173 be translated
May 1, 1686	The Royal Society read part of Letter L-168 about the particles composing cinnabar
May 8, 1686	The Royal Society read another part of Letter L-168 about gunpowder explosions and cannon lengths
May 14, 1686	Wrote Letter L-175 of 1686-05-14 to members of the Royal Society about gall-nuts found on oak trees and the germination of plants
May 22, 1686	The Royal Society read part of Letter L-173 about the structure of cotton seed, the sweat glands of the skin, and the slime of fish
May 25, 1686	Edmond Halley wrote Letter L-176 to Leeuwenhoek about a gift from the Royal Society and requesting some portraits
May 29, 1686	The Royal Society decided to send a gift to Leeuwenhoek, De Historia Piscium by Francis Willughby
June 5, 1686	The Royal Society read part of Letter L-173 about bone and wood
June 8, 1686	Bought a burial section in the Oude Kerk
June 10, 1686	Wrote Letter L-177 of 1686-06-10 to members of the Royal Society about seeds of cotton, kapok, Bupariti, and coconuts, the reproduction of shrimp and lobster, and the eggs of shell fish
June 26, 1686	The Royal Society officers declared their satisfaction with the election of Edmond Halley
July 10, 1686	The Royal Society read part of Letter L-177 about how the leaves, root, and stem are wrapped up with the seeds
July 10, 1686	Wrote Letter L-178 of 1686-07-10 to members of the Royal Society about the growth and durability of wood felled in different seasons and countries, the annual growth rings, and how wooden barrels can be made watertight
July 11, 1686	Jacob Gronovius wrote Letter L-179 to Leeuwenhoek about how his letters were received in Italy
July 17, 1686	The Royal Society ordered that Letter L-178 about the texture of oakwood be translated
September 7, 1686	Examined silkworm eggs
September 10, 1686	Wrote Letter L-180 of 1686-09-10 to Daniël Papenbroek, a cover letter for Letter L-181
September 10, 1686	Wrote Letter L-181 of 1686-09-10 to Antonio Magliabechi, a cover letter for a copy of one of his books
October 30, 1686	Wrote Letter L-182 of 1686-10-30 to Antonio Magliabechi, a cover letter for copies of two of his books
November 5, 1686	Visited by Jacob Gronovius
December 1, 1686	Edmond Halley wrote Letter L-183 to Leeuwenhoek on behalf of the Royal Society, now lost
January 1, 1687	cousin Maarten Pieters Hogenhouck (1650-1720) appointed to Veertigraad, served 1687-1720
January 1, 1687	Published Anatomia Seu Interiora Rerum (Interior Anatomy), 19 Letters from 28 - 52
January 1, 1687	Published Anatomia Seu Interiora Rerum (Interior Anatomy), Letters 43, 42, 38
January 1, 1687	Published Vervolg der Brieven (Continuation of the Letters), Letters 53 - 60
January 27, 1687	cousin Magdaleentje (Helena) Maertens Leeuwenhoek married Barent van Frijtom
February 24, 1687	Edmond Halley wrote Letter L-184 to Leeuwenhoek on behalf of the Royal Society, assuring him that the portraits he sent are received, wondering why he has not sent any observations recently, and enclosing recent numbers of Philosophical Transactions
March 1, 1687	Wrote Letter L-185 of 1687-03-01 to James II, King of England, as the dedication for one of his volumes
March 28, 1687	mentor Constantijn Huygens died
April 4, 1687	Wrote Letter L-186 of 1687-04-04 to the members of the Royal Society about the structure of the teeth of elephants, pigs, humans, oxen, and horses and about toothache
April 5, 1687	Guarantor for Johan Francisco de Raet when he became a citizen of Delft
April 16, 1687	The Royal Society ordered that Letter L-186 about teeth be translated
April 23, 1687	The Royal Society read part of Letter L-186 about the structure of teeth
May 7, 1687	The Royal Society read the latter part of Letter L-186 about the teeth of various animals
May 9, 1687	Wrote Letter L-187 of 1687-05-09 to members of the Royal Society about the structure of 'stone' of the medlar and the coffee bean and acid in plants
May 14, 1687	The Royal Society read and discussed part of Letter L-187 about embryo plants in seeds
June 4, 1687	The Royal Society read and discussed part of Letter L-187 about coffee
June 11, 1687	cousin Adriaen Lambrechts Leeuwenhoek admitted as notary
June 13, 1687	Wrote Letter L-188 of 1687-06-13 to members of the Royal Society about wheat and the seeds from a variety of plants
June 18, 1687	The Royal Society read part of Letter L-175 about gall nuts, over a year after receiving it
July 11, 1687	Wrote Letter L-189 of 1687-07-11 to members of the Royal Society about eggs of silkworms and caterpillars and humans' squinting and a theory for its cause
August 6, 1687	Wrote Letter L-190 of 1687-08-06 to members of the Royal Society about the calander and the louse and against spontaneous generation
August 6, 1687	Wrote Letter L-191 of 1687-08-06 to Robert Boyle about his recent letters
September 9, 1687	Wrote Letter L-192 of 1687-09-09 to members of the Royal Society about ant eggs, larvae and its development, feeding, sting, cocoon and nest
October 7, 1687	Appointed curator of the insolvent estate of Evert van der Sijde
October 17, 1687	Wrote Letter L-193 of 1687-10-17 to members of the Royal Society about amber, 'burned paper' from the sky, rotifers, maggots, blow flies, the stinging hairs of nettles, and the East-Indian centipede
November 24, 1687	nephew Johannes Adriaans Swalmius married Magdelena van Mierop
November 26, 1687	The Royal Society read part of Letter L-192 about the generation of ants
November 28, 1687	Wrote Letter L-194 of 1687-11-28 to members of the Royal Society about his discovery that cochineal was an insect and his experiments with cinchona bark
December 3, 1687	The Royal Society read and discussed the latter part of Letter L-192 about the generation of ants
December 11, 1687	The Royal Society ordered that Letter L-194 be translated
January 1, 1688	Published Vervolg der Brieven (Continuation of the Letters), Letters 53 - 60 (2nd)
January 1, 1688	Wrote Letter L-195 of sometime in 1688 to Robert Boyle, now lost
April 2, 1688	printer-bookseller Hendrik van Cronevelt bought the house next door
May 25, 1688	Wrote Letter L-196 of 1688-05-25 to members of the Royal Society about a medicinal root and bladderstones
July 6, 1688	Wrote Letter L-197 of 1688-07-06 to the members of the Royal Society bezoar stone, monkey stone, gout tubercles, and red coral and white coral
August 3, 1688	Wrote Letter L-198 of 1688-08-03 to the members of the Royal Society about plaster, alabaster, gypsum, Muscovite glass, cobblestone, shell lime, masonry mortar, lime, cement, sand stone, and slate
August 24, 1688	Wrote Letter L-199 of 1688-08-24 to the members of the Royal Society about gnats, horseflies; growth of branches, germination of wheat plants, the soft and hard roe of cod, and the number of sperm in a cod's soft roe
September 7, 1688	Wrote Letter L-200 of 1688-09-07 to the members of the Royal Society
September 15, 1688	Published Den Waaragtigen Omloop des Bloeds (On the True Circulation of Blood), Letter 65 (L-200)
September 23, 1688	Wrote Letter L-201 of 1688-09-23 to Melchisedec Thevenot, a cover letter for a copy of Leeuwenhoek's Letter L-200, published separately as Den waaragtigen omloop des bloeds.
January 1, 1689	Published Continuatio Epistolarum (Continuation of the Letters), Letters 53-60
January 1, 1689	Published Tweede Vervolg der Brieven (Second Continuation of the Letters), Letters 61 - 67
January 1, 1689	Wrote Letter L-202 of sometime in 1689 to Antonio Magliabechi, a cover letter for one of his books
January 12, 1689	Wrote Letter L-203 of 1689-01-12 to Robert Boyle, a cover letter for Continuatio epistolarum and a copy of Letter L-204
January 12, 1689	Wrote Letter L-204 of 1689-01-12 to the members of the Royal Society about his observation of the circulation of the blood in a variety of fish as well as a description of the construction of his ‘eel spy-glass’ and the slime on the skin of an eel
March 6, 1689	Christiaan Huygens wrote Letter L-205 to Leeuwenhoek, thanking him for the gift of a mangrove tree and inquires whether L.’s observations of the circulation of the blood could also be seen in the wings of bats, the legs of ducks, and the ears of rats
April 1, 1689	Did not write any letters between 1689 04-01 and 1691 09-18
April 1, 1689	Wrote Letter L-206 of 1689-04-01 to the members of the Royal Society
April 23, 1689	Appointed guardian of the children of Jacob Bellart
May 27, 1689	Anthonie Heinsius became Grand Pensionary of the States of Holland
June 21, 1689	nephew Adriaan Johannes Swalmius baptized, witnessed by Antony and Cornelia
October 1, 1689	Wrote Letter L-207 of October 1689 to Christiaan Huygens about sending books to father Constantijn Huygens in London
October 19, 1689	cousin Adriaen Lambrechts Leeuwenhoek married Eva Jacobs Overschie
March 6, 1690	Christiaan Huygens wrote Letter L-208 to Leeuwenhoek about liquids in glass balls and Iceland crystal
April 3, 1690	cousin Maarten Lambrechts Leeuwenhoek married Margareta Pieters van Limburg
April 17, 1690	daughter Maria made a will
September 7, 1690	Bought the other part of the garden outside the walls of the city
January 1, 1691	Published Onsigtbare Verborgentheden (Invisible Mysteries), Letters 38, 42, 43 (2nd)
March 2, 1691	Gottfried Leibniz wrote to Christiaan Huygens praising Leeuwenhoek, "who tells me what he observes"
May 27, 1691	Antonio Magliabechi wrote Letter L-209 of 1691-05-27 to Leeuwenhoek about book news and Leibniz's reaction to some of Leeuwenhoek's observations
September 18, 1691	Wrote Letter L-210 of 1691-09-18 to Antonio Magliabechi about
September 21, 1691	William Stanley wrote Letter L-211 of 1691-09-21 to Leeuwenhoek, a courtesy letter
November 27, 1691	Wrote Letter L-212 of 1691-11-27 to the members of the Royal Society about blood, chyle, and an experiment to discover the volume of water when it is cold and when it is heated
December 2, 1691	mentor Cornelis 's Gravesande died
December 5, 1691	mentor Cornelis 's Gravesande buried
December 6, 1691	brother-in-law Jan Jacobs de Molijn buried
January 1, 1692	William Molyneaux wrote about a visit to Leeuwenhoek
January 4, 1692	Wrote Letter L-213 of 1692-01-04 to the members of the Royal Society about bladder and kidney stones and a chalk-like substance from a gout stone
January 13, 1692	niece Geertruijt Jans de Molijn inherited property from her father Jan Jacobs
February 1, 1692	Robert Hooke called Leeuwenhoek the microscope's "single votary"
February 1, 1692	Wrote Letter L-214 of 1692-02-01 to the members of the Royal Society about various peppers and their taste, tea and its effects of tea on digestion, and Spanish fly
February 12, 1692	Richard Waller wrote Letter L-215 to Leeuwenhoek about his recent observations and the structure of grass
March 7, 1692	Wrote Letter L-216 of 1692-03-07 to the members of the Royal Society about corn-weevels, corn-moths, caterpillars, butterflies, calanders, lice in corn-lofts, little animals in rain water, black-flies in blossoms, and maggots in cheese
March 19, 1692	Reimbursed for purchase of distilled water and wine
April 22, 1692	Wrote Letter L-217 of 1692-04-22 to Richard Waller about the construction of an air pump and experiments with different liquids, seeds and small stones in urine, a hog's hair in the skin of a child, and grains of wheat
June 24, 1692	Antonio Magliabechi wrote Letter L-219 of 1692-06-24 to Leeuwenhoek about recent books that he thought might be of interest by Ramazzini and Guiglielmini
June 24, 1692	Wrote Letter L-218 of 1692-06-24 to the members of the Royal Society about more experiments with his air-pump, the structure of and blood in an insect's wing, a grey owlet moth, and the wing of a very small fly
July 22, 1692	Christiaan Huygens began second series of observations of microbes replicating and expanding on Leeuwenhoek's
August 12, 1692	Wrote Letter L-220 of 1692-08-12 to the members of the Royal Society about the shaft of a bird's feather as used in a quill, the lens and cornea of the human and calf eyes, 'wood-pipes' in different species of wood, bulrushes, and pine and lime wood
September 16, 1692	Wrote Letter L-221 of 1692-09-16 to the members of the Royal Society about little animals in dental tartar, theories of eel reproduction, worms in eel intestines, and blood vessels in grasshoppers
September 23, 1692	Wrote Letter L-222 of 1692-09-23 to Mary, Queen of Great Britain, the dedication to Derde Vervolg der Brieven
October 20, 1692	Christiaan Huygens wrote Letter L-223 to Leeuwenhoek about the procreation of eels and spontaneous generation and praised his work and diligence
November 29, 1692	cousin Sara Maertens Leeuwenhoek married Cornelis Luda
December 21, 1692	cousin Jacob Adriaens Leeuwenhoek (1692-1724) baptized

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