Robert Hooke (1635–1703) was an English artist, biologist, physicist, engineer, architect, and inventor, but his crowning glory was his book Micrographia: or Some Physiological Descriptions of Minute Bodies made by Magnifying Glasses. First published 1665, with a second publishing in 1667, Micrographia was a masterpiece that provided an exquisitely illustrated introduction to the previously unknown microscopic world. The book contains large etchings of insects and plant matter in high detail, inspired by his view through a microscope. The etchings provide insight into the ornate body structures of flies, fleas, and gnats, that are not visible to the naked eye.
Here at the National Library of Medicine our History of Medicine Division holds a copy of both the 1665 and 1667 editions of Micrographia. Hooke’s microscope is located at our sister institution the National Museum of Health and Medicine in Silver Spring, Maryland.
For an artist to make etchings, like those in Micrographia, a polished copper plate was coated with an acid-resistant layer of wax or varnish and the image scratched through the layer with a needle to expose the metal beneath. The plate was then submerged in acid until the intaglio (recessed) image was etched into the plate. After the printing of the two editions of Micrographia, Hooke moved onto other projects most notably assisting Christopher Wren (1632–1723) redesign London after the Great Fire of 1666.
After 1667, the etching plates from Micrographia sat unused until they were rediscovered and reprinted as Micrographia Restaurata by Henry Baker in 1745.
When Hooke looked through a microscope at the structure of cork bark he was struck by the orderly little squares that reminded him of cells, the rooms in a monastery where monks lived. Hooke called the little boxes in the cork bark “cells” and today Hooke is recognized as the first person to use the word in its now-common scientific context. These three illustrations were all made from the same copper plate over a period of eighty years, showing the microscopic structure of cork bark.
Hooke was not the only one exploring the powers of the microscope, but his highly detailed images won him lasting influence. There had been a few who attempted what Hooke would famously accomplish, and many others who would follow, expanding and refining what Hooke had done by reading the tracts he left for them. Henry Power, another pioneer of the microscope, published his work before Hooke’s Micrographia, but his book had only a few crude woodcuts to describe the tiny objects he viewed under magnification.
Although Hooke had a knack for intuitively grasping great scientific truths without always understanding the hard science that lay beneath, this led him to claim credit for the discoveries of others, and to a lifetime of public controversy.
Hooke’s work and legacy in print did positively influence many in the scientific community including Henry Baker, the printer of Micrographia Restaurata. Baker also drew schematic plans for creating a microscope that clearly used Hooke’s instrument as inspiration. He published them in The Microscope Made Easy. Additionally, the English clergyman William Derham edited and published some of Hooke’s works after the author’s death, including illustrations not previously seen by the public.
Possibly the person most influenced by Hooke was his greatest rival and successor in the world of microscopy, Antoni van Leeuwenhœk (1632–1723). Although the two never met, Leeuwenhœk was clearly motivated by Hooke’s accomplishments, as he too ground his own microscope lenses and built his own equipment. In his early years, Leeuwenhœk sent his findings to the Royal Society in London (Hooke’s long-time employer), where they were published in the society’s Philosophical Transactions, the first peer-reviewed scientific journal. Leeuwenhœk’s later instruments were far stronger than Hooke’s and allowed him to see microscopic structures too small for Hooke’s equipment to capture.
This post was adapted by Cecelia Vetter from an online version of an exhibition curated by Stephen Greenberg held at the National Library of Medicine in 2007.
Stephen J. Greenberg, PhD, is Head of Rare Books and Early Manuscripts for the History of Medicine Division at the National Library of Medicine.
Cecelia Vetter is a National Library of Medicine 2018-2019 Associate Fellow completing her second year at Strauss Health Sciences Library at the University of Colorado. She received her B.A. from Washington University in St. Louis and her M.L.I.S. from the University of Maryland, College Park.