Antoni van Leeuwenhoek and measuring the invisible

Full title

Antoni van Leeuwenhoek and measuring the invisible: The context of 16th and 17th century micrometry

Abstract

This article explores the impact of 16th and 17th-century developments in micrometry on the methods Antoni van Leeuwenhoek employed to measure the microscopic creatures he discovered in various samples collected from his acquaintances and from local water sources. While other publications have presented Leeuwenhoek’s measurement methods, an examination of the context of his techniques is missing. These previous measurement methods, driven by the need to improve navigation, surveying, astronomy, and ballistics, may have had an impact on Leeuwenhoek’s methods. Leeuwenhoek was educated principally in the mercantile guild system in Amsterdam and Delft. He rose to positions of responsibility within Delft municipal government. These were the years that led up to his first investigations using the single-lens microscopes he became expert at creating, and that led to his first letter to the Royal Society in 1673. He also took measures to train in surveying and liquid assaying practices existing in his time, disciplines that were influenced by Pedro Nunes, Pierre Vernier, Rene Descartes, and others. While we may never know what inspired Leeuwenhoek’s methods, the argument is presented that there were sufficient influences in his life to shape his approach to measuring the invisible.

from the conclusion

It is difficult to know Leeuwenhoek’s motivation for his observations. It is also challenging to know what inspired his fledgling metrology. Certainly, he was raised in an environment that valued measurement, whether it was of baskets, cloth, land, or liquids. He was repeatedly placed in, or selected, environments where he learned more than was expected of him, particularly in his passage of the master exams for cloth merchant. He was skilled at his business and impressed his fellow Delftians to the extent that he gained positions of responsibility in local government as a burgher, surveyor, and wijnroeier.

An exciting aspect of Leeuwenhoek’s observations is that he examined everything from chemical crystals and mold growth to the reproduction of vinegar eels. It did not matter to him because he was not raised in a specific discipline with its compartmentalization and prejudices. If there was something to view, he found it with his tiny lenses. If it moved, he wrote about it. If it grew, he described it. If it dissolved, he watched it disappear, then watched as it recrystallized out of the cooling water. If he managed to form a salt of some compound in circumstances that controlled exposure to air, he would observe its color changes when he allowed air to interact. If he had documented something in his early observations, he sometimes returned to the object later and observed it again, changing descriptions, measurements, and drawings to reflect his experience, knowledge, skills, or lens improvements.