“It almost seems as if Van Leeuwenhoek knew that a new microworld was to unfold,” Cocquyt told me. One of his scientific rivals, Johannes Hudde, later said, “isn't it surprising that we never had the creativity to use these ball lenses to observe little things against the daylight, and that an uneducated and ignorant man such as Van Leeuwenhoek had to be the one to teach this to us.”
Van Leeuwenhoek was the fifth son of a basket maker, born in the Delft—a small port city in South Holland known for its picturesque waterways, pottery, and beer. At 16 he departed for an apprenticeship as a dry goods seller in Amsterdam, but six years later he returned home, married the daughter of a well-regarded local brewer, and purchased his own fabric shop.
He spent his twenties growing a successful business but suffered immense personal tragedy. Of the five children he and his wife Barbara had in their 12 years of marriage, four died in infancy; Barbara would soon follow. Few biographical details have survived from his first decade back in Delft, but he held a number of odd jobs in addition to running his draper shop, including working as chief custodian of the local courthouse. A stint as town surveyor offers one clue to Van Leeuwenhoek’s budding scientific potential: proof he had learned geometry.
His obsession with magnifying lenses began sometime in his mid-thirties. How he came upon it isn’t known. His writings never touch on its origins. Perhaps, as many have speculated, he started using lenses to inspect the quality of his cloth. Or maybe he got caught up in the public mania for microscopes following the publication of Hooke’s Micrographia. Van Leeuwenhoek never mentions the book in any of his letters, but the timing aligns, and he clearly read it: Some of his experiments replicate Hooke’s too closely to be a coincidence. But regardless of how Van Leeuwenhoek got into microscopy, by 1668 he had begun pursuing it with an unusual tenacity. While traveling in England that year, he saw the white cliffs of Dover and felt compelled to examine their chalky slopes beneath his lens: “I observed that chalk consisteth of very small transparent particles; and these transparent particles lying one upon another, is, methinks now, the reason why chalk is white.”
By 1673, though still operating in complete obscurity, he was already making the world’s most powerful lenses. Hi...