Plate 4 from Americae Retectio
by Johannes Stradanus

Exploring the Microworld


Among the new instruments developed for the investigation of the natural world, microscopes were important for revealing a previously unknown yet vast world of living things as well as the intricate structures of inanimate objects. In Amsterdam, Anton van Leeuwenhoeck (1632-1723), a draper's apprentice who used magnifying glasses in his daily work to examine textiles, learned how to make his own lenses and how to combine them in order to build increasingly powerful microscopes, finally reaching a magnification of 270 times. Leeuwenhoeck, who was aware of theories that all material objects were composed of tiny "globules" or "corpuscles," began to explore the microworld, and was astounded to find that it swarmed with minuscule living creatures, which he refers to as "wee little beasties." He was the first to see protozoa and bacteria invisible to the unassisted eye, a feat for which he earned international renown and was admitted to England's Royal Society.

The English natural philosopher Robert Hooke's wide-ranging investigations included mechanics, astronomy, meteorology, as well as microscopy. Hooke made a detailed series of observations of both living and inanimate things with a compound microscope that he had constructed. He was employed as the Curator of Experiments of the Royal Society between 1662 and 1677. His ability to construct and use scientific instruments was unparalleled in his lifetime. Concerning the microscope, he hoped that ever more powerful instruments would reveal the particular size and shapes of the particles that combined to make up material objects. Hooke coupled powerful microscopes with very bright sources of illumination and made beautiful and breathtakingly detailed drawings of the objects that he viewed.

The results of his microscopic research were published in what Lisa Jardine called "the seventeenth-century equivalent to a coffee-table book," his Micrographia, first published in London by the Royal Society in 1665. Hooke's book was designed in part to demonstrate that the Royal Society's program of inquiry was addressing important intellectual and social problems. It also served as an example of the Society's methodology, and was an answer to the question of how best to communicate these themes to the reading public.

Hooke tells us in the Preface to Micrographia that he made careful drawings, endeavoring to "discover the true appearance [of each object under study] and next to make a plain representation of it." Click Here for a Larger ViewThis proved quite difficult, so he "never began to make any draft before by many examinations in several lights, and in several positions [relative] to these lights, [he] had discovered the true form." The images were then engraved on copper plates from which the book's astoundingly detailed plates—some folding from three to five times—were printed.

Micrographia presents a central thesis that the world is not, in fact, what it appears to be to the naked eye: that it includes many invisible things and that familiar objects look completely different under the microscope. Hooke makes his case by accumulating sixty "Observations" and illustrating his argument with thirty-eight plates (some displaying several images). To present this disorienting message, Hooke chooses a humble, very familiar household object, the point of a needle, explaining that it appeared through the microscope "about a quarter of an inch broad, not round nor flat, but irregular and uneven; so that it seem'd to have been big enough to have afforded a hundred armed Mites room enough to be rang'd by each other without endangering the breaking one anothers necks, by being thrust off on either side" (2). Hooke marvels at the "multitude of holes and scratches and ruggedness" on what we could expect to be a smooth surface. A system of small letters (which are the "micrographia" of the title) links text to image, pointing out what seem to be "holes made by some small specks of Rust" (2). Aware of how disturbing his readers might find this gap between expected appearance and reality, Hooke immediately suggests that this man-made needle bears "onely [sic] so many marks of the rudeness and bungling of Art, [and, if viewed at even greater magnification, would have even] less appearance . . . of beauty; whereas in the works of Nature, the deepest Discoveries shew us the greatest Excellences. An evident Argument, that he that was the Author of all these things was . . . Omnipotent; being able to include as great a variety of parts and contrivances in the yet smallest Discernable Point, as in those vaster bodies (which comparatively are called also Points) such as the Earth, Sun, or Planets" (2). Hooke, writing as an orthodox Christian, rushes to reassure his readers that continued observations with his microscope will amass compelling evidence of God's handiwork in Nature. One might even see the use of this instrument as enabling humankind to read divine "micrographia."

The passage just quoted, which ends by referring to observing the heavens using a telescope, allowing what appears only to be distant points to be seen more clearly, is, in miniature, a model of the architecture of the entire book, for it is with a plate showing the surface of the Moon and the Pleiades constellation that Hooke ends his Micrographia.

Colin Dickson
Washington College

Suggested Reading

Bennett, J.A. "Robert Hooke as Mechanic and Natural Philosopher." Notes and Records of the Royal Society 35 (1980-1981): 33-48.

Gunther, Robert [William] Theodore. Early Science in Oxford. Vol 13, The Life and Work of Robert Hooke Part 5, Micrographia. Oxford: Oxford University Press, 1938.

Harwood, John T. "Rhetoric and graphics in Micrographia." In Robert Hooke: New studies, edited by Hunter Schaffer, Michael Schaffer, and Simon Schaffer, 119-47. Woodbridge: Boydell Press, 1989.

Jardine, Lisa. Ingenious pursuits: Building the Scientific Revolution. New York: Nan A. Talese/Doubleday, 1999.

Johns, Adrian. The Nature of the book: Print and knowledge in the making. Chicago: University of Chicago Press, 1998.

Shapin, Steven. The Scientific Revolution. Chicago: University of Chicago Press, 1996.

Wilson, Catherine. The Invisible World: Early Modern Philosophy and the Invention of the Microscope. Princeton: Princeton University Press, 1995.