Pages tagged scientist

Leeuwenhoek's Microscopes

His microscope was a superior design because it solved his problems better than the alternatives. It was a dead-end design because it was too hard to make and much harder to use than the double-lens microscope.


Biologists today are seldom well-versed in the history of science. If they know anything about Leeuwenhoek, it's "animalcules", usually spoken with a little grin. So quaint! The word animalcules is a diminutive of animal. Its first use in English is 1599 and it wasn't used much after the mid-1880's. It referred to small animals, from insects to mice, but usually invertebrates. As the Google Ngram below shows, it was replaced by microbes around the time of Pasteur and Koch.

As Science Began

How the self-taught van Leeuwenhoek helped give birth to the scientific method, especially peer review.

Counting the Little Animals

How small? How many? How van Leeuwenhoek calibrated and counted the multitude of tiny things he discovered.

How to dissect animals and plants

The Dutch were interested in dissection of human bodies for both forensic and scientific purposes. City anatomists Cornelis 's Gravesande Collectors of rarities and curiosities noted in Engel who lived in Delft during Leeuwenhoek's lifetime:

Leeuwenhoek's Cabinet of Wonders

All 140 figures, originally copperplate etchings on 32 plates that accompanied half the of 46 letters of the Send-Brieven. Organized by groups of specimens.

Period 1 - 1673-1679

The 42 letters from Letter 1 of April 28, 1673 (AB 1), through Letter 27 of February 21, 1679 (AB 42) before Leeuwenhoek began publishing them himself. Of the 32 letters with scientific observations, 16 of them had a total of 65 figures. Of the 28 letters with scientific observations that he sent to the Royal Society, 17 were excerpted in Philosophical Transactions.

Period 2 - 1679-1686

The 54 letters from Letter 28 of April 25, 1679 (AB 43) through the letter of October 30, 1686 (AB 96). Of the 36 letters with scientific observations, 25 of them had a total of 219 figures. Leeuwenhoek published 25 of these letters in Works I.

Period 3 - 1687-1694

The 42 letters from Letter 53 of April 4, 1687 (AB 98) through Letter 83 of April 4, 1694 (AB 137). Of the 33 letters with scientific observations, 28 of them had a total of 315 figures. Leeuwenhoek published 31 of these letters in Works II.

Period 4 - 1694-1702

The 99 letters from the letter of May 26, 1694 (AB 138) through Letter 146 of April 20, 1702 (AB 236). Of the 73 letters with scientific observations, 35 of them had a total of 194 figures. Leeuwenhoek published 63 of these letters in Works III.

Period 5 - 1702-1712

The 58 letters from the Letter [147] of May 28, 1702 (AB 237) through Letter [190] of June 10, 1712 (AB 294). Of the 49 letters with scientific observations, 29 of them had a total of 244 figures. The letters between Sevende Vervolg and Send-Brieven. Hans Sloane published 44 in Philosophical Transactions.

Period 6 - 1712-1719

The 52 letters from the letter of November 8, 1712 (AB 295) through the letter of November 28, 1717 (AB 346). Of the 46 letters with scientific observations, 22 of them had a total of 144 figures. Leeuwenhoek published all 46 of these letters, what he called Send-Brieven, in Works IV.

Period 7 - 1720-1723

The 18 letters from Letter [XLVII] of January 9, 1720 (AB 347) through the letter of August 1723 (AB 364). Of the 15 letters with scientific observations, 9 of them had a total of 46 figures. The letters after Leeuwenhoek stopped publishing them himself; James Jurin excerpted the 15 letters with scientific observations in Philosophical Transactions.