Letters written by Leeuwenhoek during Period 5

Alle de Brieven / Collected Letters has over 350 letters. However, only those in this chronology that Leeuwenhoek designated Letter 1, Letter 2, etc. did he consider to contain publishable microscopic observations.

Date
April 28, 1702 Wrote Letter L-405 of 1702-04-28 to the members of the Royal Society about little animals and air bubbles in rain water and the circulation of blood in an eel
December 8, 1702 Wrote Letter L-407 of 1702-12-08 to John Chamberlayne about cleaning and preserving teeth by polishing them with salt and ash of tobacco and whether tea and coffee harm teeth; requested a book on Peruvian silver mines
December 25, 1702 Wrote Letter L-408 of 1702-12-25 to the members of the Royal Society about duckweed, its roots and reproduction, the little animals attached to it, and asexual reproduction
February 5, 1703 Wrote Letter L-409 of 1703-02-05 to the members of the Royal Society about colony-forming little animals from Delft canal water, dissolving silver and gold in acids, and why there is little duckweed on the surface of water in cold weather
February 26, 1703 Wrote Letter L-410 of 1703-02-26 to the members of the Royal Society about the structure and germination of pips of oranges from Surinam and Curaçao
November 3, 1703 Wrote Letter L-412 of 1703-11-03 to Hans Sloane to thank him for sending recent numbers of Philosophical Transactions and the book on Peruvian silver mines, also as a cover letter for Letter L-413
November 3, 1703 Wrote Letter L-413 of 1703-11-03 to the members of the Royal Society about the liver fluke in soil from meadows, worms and other little animals in soil, and a theory about how they propogate
December 4, 1703 Wrote Letter L-414 of 1703-12-04 to the members of the Royal Society about the shape of a grain of fine sand from the Dutch East Indies
January 8, 1704 Wrote Letter L-415 of 1704-01-08 to the members of the Royal Society about salt crystals out of rainwater that during a "frightful storm" in December had dashed against the windows of his house
February 1, 1704 Wrote Letter L-416 of 1704-02-01 to the members of the Royal Society about red sandstone from the cathedral at Utrecht compared to diamond, his theory about the origin of diamonds, and marble, Bentheim stone, alabaster, and gold and silver ore
February 11, 1704 Wrote Letter L-418 of 1704-02-11 to Pieter Valckenier about rock crystal, its origins in the mountains, and fossils of ocean fish found in his Swiss mountains
February 15, 1704 Wrote Letter L-419 of mid-February 1704 to Siewert Centen to refute his contention that cochineal must be a plant, not an animal
March 21, 1704 Wrote Letter L-422 of 1704-03-21 to the members of the Royal Society about cochineal and the insects that are the source of this dye
July 22, 1704 Wrote Letter L-423 of 1704-07-22 to the members of the Royal Society about muscle fibers of whales, the structure of the eyes' lenses of whales and cod, and his theory about why fish have no eyelids
September 1, 1704 Wrote Letter L-424 of sometime before 16 September 1704 to Pieter Hotton about the canals that raise the yellow sap in a common plant
September 16, 1704 Wrote Letter L-426 of 1704-09-16 to the members of the Royal Society about leaves of aloe and a plant called dragon's blood sent to him by Pieter Hotton with Letter L-425
October 3, 1704 Wrote Letter L-427 of 1704-10-03 to John Chamberlayne as a follow-up to Letter L-407 about tobbacco ashes, the salt crystals obtained from them, and an oily substance obtained by heating the ashes of tobacco
November 4, 1704 Wrote Letter L-428 of 1704-11-04 to the members of the Royal Society about little animals with two wheels, found on duckweed, how they move, their parasites, and the theory that sea water makes land more fertile
December 13, 1704 Wrote Letter L-431 of 1704-12-13 to the members of the Royal Society about the origin of rock-crystal and a description and analysis of fossils of sea animals and two Roman dice all found in Switzerland and given to him by Pieter Valkenier
March 3, 1705 Wrote Letter L-433 of 1705-03-03 to the members of the Royal Society about silver deposits on his own hands after he mixed gold and silver with acid and treatment of a callous on his own finger with vitriol and then acid
March 3, 1705 Wrote Letter L-434 of 1705-03-03 to John Chamberlayne about vitrified matter from a haystack that had caught fire, sent to Leeuwenhoek with Letter L-429
March 12, 1705 Wrote Letter L-436 of 1705-03-12 to Antonio Magliabechi about precipitating silver from aqua fortis, silver sulphate crystals, their comparison with rock crystal, saltpetre, and sugar candy
March 27, 1705 Wrote Letter L-437 of 1705-03-27 to the members of the Royal Society about his theory that bark tissue is formed from wood; cross-sections and pictures of vessels and cells of bark and wood tissue of cherry, birch, cinnamon, and lime trees and from cork
April 24, 1705 Wrote Letter L-438 of 1705-04-24 to the members of the Royal Society about a fern and its seed capsules and an experiment to open and close them
May 25, 1705 Wrote Letter L-439 of 1705-05-25 to the members of the Royal Society about crystals from various minerals that Pieter Valkenier left after his recent visit and experiments to dissolve and recrystallize them
December 18, 1705 Wrote Letter L-441 of 1705-12-18 to Francesco Corner about the structure of a pearl compared to that of an oyster's shell, salts from pearls and oysters' shells heated and afterwards dissolved, and an argument against the grit of pearls as medicine
December 29, 1705 Wrote Letter L-442 of 1705-12-29 to the members of the Royal Society about pumice stone, its origins, and its salts, sponge and a theory about how it absorbs water, and coral
March 7, 1706 Wrote Letter L-444 of 1706-03-07 to Govert Bidloo to follow up on his visit earlier that day about what Leeuwenhoek discovered in the intestines they had viewed
March 19, 1706 Wrote Letter L-446 of 1706-03-19 to the members of the Royal Society about an East Indian tree and mixing his own blood with the crushed seed of the tree and water, the effects of a drink made from hemp seed, and a dissected hemp seed
April 20, 1706 Wrote Letter L-447 of 1706-04-20 to the members of the Royal Society about a piece of hanged woman's intestinal wall brought to him by Govert Bidloo
June 1, 1706 Wrote Letter L-448 of 1706-06-01 to the members of the Royal Society about the structure of a sheep's spleen and a flea's organ for stinging and sucking
January 1, 1707 Wrote Letter L-449 of 1707-01-01 to Angelus van Wikhuysen about the use of cinchona bark as a remedy
May 17, 1707 Wrote Letter L-452 of 1707-05-17 to John Chamberlayne to complain that his four most recent letters to the Society had not been answered; about a bezoar stone and the visit of Corner; offered to send a copy of Letter L-436 to Magliabechi
July 5, 1707 Wrote Letter L-454 of 1707-07-05 to the members of the Royal Society to acknowledge the receipt of Letter L-453 and to cover the enclosed copy of Letter L-436 of 12 March 1705 to Magliabechi
July 12, 1707 Wrote Letter L-455 of 1707-07-12 to the members of the Royal Society as thanks for numbers of Philosophical Transactions and as cover to a copy of Letter L-441 to Corner; mentioned the visit of Gilbert Burnet
July 25, 1707 Wrote Letter L-457 of 1707-07-25 to the members of the Royal Society about cinchona bark and using it as a treatment for fever
August 10, 1707 Wrote Letter L-458 of 1707-08-10 to Anthonie Heinsius as a cover letter for a copy of Letter L-457 of 25 July 1707 to the Royal Society
October 18, 1707 Wrote Letter L-459 of 1707-10-18 to the members of the Royal Society about the fur on his own tongue after an attack of fever, the fur of a thrush patient, and a theory about the origin of tongue fur
November 22, 1707 Wrote Letter L-461 of 1707-11-22 to the members of the Royal Society about a hairy substance, received with Letter L-460, supposedly excreted by a woman suffering from a kidney infection
December 6, 1707 Wrote Letter L-462 of 1707-12-06 to the members of the Royal Society about the tongue of an ox, its skin and papillae, and the tongue of a pig with its papillae and muscle fibres
January 1, 1708 Wrote Letter L-463 of 1708-01-01 to the members of the Royal Society about the composition of red coral, the effects when heated and when dissolved in aqua fortis and boiling rain water, and crystals in dissolved coral
June 29, 1708 Wrote Letter L-464 of 1708-06-29 to the members of the Royal Society about his further observations of the white furry substance on his own tongue during attacks of fever
August 28, 1708 Wrote Letter L-467 of 1708-08-28 to the members of the Royal Society about how an eel's heart and the valves in the vien of its tail work; his own pulse and pulsation of the heart of an eel and a pike
October 9, 1708 Wrote Letter L-468 of 1708-10-09 to the members of the Royal Society about the mucous membrane in the palate and in the nose of a cow and about its tongue
September 10, 1709 Wrote Letter L-470 of 1709-09-10 to Hans Sloane, a cover letter for the following Letter L-471 to John Chamberlayne.
September 10, 1709 Wrote Letter L-471 of 1709-09-10 to John Chamberlayne about the cutting edge of a razor and its nicks as well as its setting and maintenance
November 22, 1709 Wrote Letter L-472 of 1709-11-22 to John Chamberlayne about human beard hairs and muscle fibres of a cod, both cut off with a razor
January 14, 1710 Wrote Letter L-474 of 1710-01-14 to the members of the Royal Society about Alexander Stuart's visit, blood circulation in eels, crystallisation of sugar, minerals from Hungary, and his new fish viewer for visitors to see blood circulating in an eel's tail
February 2, 1710 Wrote Letter L-475 of 1710-02-21 to the members of the Royal Society about the shape and crystallization of diamonds
June 6, 1710 Wrote Letter L-476 of 1710-06-06 to the members of the Royal Society about silver dissolved in aqua fortis
November 11, 1710 Wrote Letter L-477 of 1710-11-11 to the members of the Royal Society about what happened when he dissolved gold dust from Guinea in aqua regia
August 15, 1711 Wrote Letter L-479 of 1711-08-15 to Anthonie Heinsius as a cover letter for Philosophical Transactions, vol. 26, no. 319, with Leeuwenhoek's article on the pulse and copies of notes on gold from Guinea and hailstones
August 18, 1711 Wrote Letter L-480 of 1711-08-18 to James Petiver about the sperm of young rams and to explain what happened when Petiver tried to visited
September 22, 1711 Wrote Letter L-481 of 1711-09-22 to the members of the Royal Society about mites, their reproduction, eggs, larvae, a calculation of the size of a mite egg, the hair of a honey-bee, and metamorphis of larvae from dried fish into a full-grown animal
November 23, 1711 Wrote Letter L-482 of 1711-11-23 to Anthonie Heinsius about claims by Fryer and Kircher supporting spontaneous generation, which Leeuwenhoek rejected; gold, copper, and silver dissolved in aqua fortis and the separation of gold and copper
December 29, 1711 Wrote Letter L-483 of 1711-12-29 to Anthonie Heinsius, a cover letter for Letter L-484, naming the author of the article in Philosophical Transactions that he criticizes but does not name in the following letter, meant for publication
December 29, 1711 Wrote Letter L-484 of 1711-12-29 to Anthonie Heinsius to refute an article in Philosophical Transactions; he calculates the quantity of blood propelled by each heartbeat and estimates how often the total blood volume circulates through the body
March 1, 1712 Wrote Letter L-485 of 1712-03-01 to the members of the Royal Society about the skin and flesh of a whale, its seminal vessels, and its blood with comparisons to the blood of other fish
April 12, 1712 Wrote Letter L-486 of 1712-04-12 to the members of the Royal Society about the structure of the genetalia of a female elephant and the structure of an elephant's skin
June 10, 1712 Wrote Letter L-487 of 1712-06-10 to the members of the Royal Society about little animals on a mussel's shell, the ciliar motion of the gills, and the intestines and ovaries of mussels
January 1, 1713 Wrote Letter L-491 of a few years before 1713 to Jan Meerman how barley is filling, but provides little nourishment, also about a membrane in the barley