In 1665, Robert Hooke published a book that introduced a whole new realm of the living world that was too small to see with the naked eye. His book Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses, with Observations and Inquiries Thereupon contained 38 copperplate illustrations of the specimens he examined, including an ant, moth, fly, louse, mold, flea, mite, seeds, cork, and sponge. Readers were fascinated with the details of life on such a small scale. Hooke had been a painter, and he closely oversaw the engraving of the plates so that they matched what he saw through the microscope lens. His engravings are surprisingly similar to images of the same specimens taken with modern microscopes. Many of the engravings are so large that they needed multiple folds to fit inside the book. For some of the illustrations, he included the circular shape of the eyepiece to make the image even more engaging.
Robert Hooke was a member of and Curator of Experiments for the Royal Society of London. This was an early group of intellectuals (lawyers, merchants, physicians, and aristocrats) in London and Oxford that met to discuss their observations of the natural world. They were interested in scientific learning that came from their direct observation and reproducible experiments, instead of learning only from the writings of ancient Greek scholars. Hooke’s book was written as a series of 60 observations and included details about his equipment and his preparation of specimens. The Royal Society created an interactive, full-text scan of Micrographia that is publicly accessible.
Although Hooke’s first book examined inanimate specimens, other scientists like Antoni van Leeuwenhoek would soon inspect tiny living “animalcules” in well water, rain water, and sea water. He was also a member of the Royal Society and was the first person to see and describe bacteria around 1674. (It would take more than 100 years for scientists to understand the role of bacteria in infections.) Van Leeuwenhoek constructed his first microscopes to inspect the quality of cloth in his drapery shop. His microscopes were much simpler than the one used by Robert Hooke, and he spent a lot of time making his own glass lenses. His microscopes were capable of magnification of up to 250x. In addition to two copies of Hooke’s Micrographia, the Falk Library History of Medicine collection also contains multiple examples of van Leeuwenhoek’s observations.
~Cassie Nespor