Robert Hooke’s Micrographia (London, 1667)
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The Book of the Month for September 2024 is Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon (London, 1667), by the English scientist Robert Hooke (1635–1703). This work by Hooke offers ground-breaking insights into microscopic structures, revolutionizing scientific observation in the seventeenth century.
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Robert Hooke, Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon (London, 1667), title page.
We know little about the journey of the volume to the Worth Library, but both the binding and an inscription on the title page imply that a colleague of Worth’s, Richard Tighe (1678–1736), a Member of Parliament and a trustee and governor of Dr Steevens’ Hospital, gifted it to Edward Worth (1676–1733), who left his books to the hospital in his will.[1] The seventeenth-century binding is gold-tooled with the coat of arms of the Tighe family.[2] In addition, the title page bears the inscription ‘Ex dono R. Tighe’, and displays the coat of arms of the Royal Society of London, with the motto ‘nullius in verba’ meaning ‘take nobody’s words for it’. John Evelyn (1620–1706), a prominent author and member of the Society, along with other participants decided upon this motto for the Royal Society after its founding in 1660.[3] Robert Hooke included this on the title page of the text to show his gratitude towards the members. Hooke was an exemplary scientist and produced discoveries in many scientific fields, greatly benefiting the Society. He was admitted into the Royal Society in late 1662.
Robert Hooke was born in the village of Freshwater on the Isle of Wight, and as a child, he enjoyed constructing miniature mechanical devices, such as wooden clocks and small ship models.[4] His skill at drawing sparked an interest in observation. He fueled it through an apprenticeship with the painter Sir Peter Lely (1618–80), using inheritance money after his father died in 1648. Hooke excelled in many intellectual areas, including language, science, mathematics, and musical studies, earning recognition as a virtuoso. He later became employed by the Royal Society of London, where he began to conduct investigations as ‘Curator of Experiments’. The Society recognized his exceptional talent and appointed him Curator of the Office, a position honouring his significant contributions.[5] Hooke’s experiments boosted scientific understanding, yielding significant breakthroughs in theoretical knowledge. In his Micrographia, he discovered tiny structures he named ‘cells’ and included a calculation of the height of the atmosphere based on the inverse relation between pressure and volume of gases (Boyle’s Law).[6]
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Robert Hooke, Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon (London, 1667), plate I, depicting a microscope.
The Council of the Royal Society approved Robert Hooke’s most famous work, Micrographia on 23 November 1664. The printers to the Society, John Martyn (1617/18–80) and James Allestry (d. 1670), printed the volume initially in 1665, and the title page indicated that the book would be available at their shop at the ‘Bell in St. Paul’s Church Yard’.[7] The title page of the 1667 edition held in the Edward Worth Library states that it was available for sale from John Martyn’s shop at the ‘Bell a little without Temple Barr’. In England’s golden age of science, Robert Hooke dedicated his book to King Charles II (1630–85). He saw the monarch’s peaceful rule as beneficial for research. Hooke felt compelled to present his findings, nurtured by royal stability, back to the crown. This gesture symbolized the symbiosis between sovereign and scholar in an era of intellectual growth. The author also dedicates the book to the Royal Society, of which he was recently made a fellow.
Micrographia contains many exquisite illustrations, drawn by Hooke himself. The images represent the detail and specificity that the microscope provided Hooke with, and the subjects captured within the volume’s pages express the advancement compared to other drawings of microorganisms at the time. To create these images, Hooke used a polished metal plate. He painted it with an acid-resistant layer of wax or varnish, then scratched the drawing through this layer with a needle to show the metal beneath. Finally, the plate was immersed in acid until the intaglio image was engraved into the plate.[8] Beyond the artistry of its illustrations, Micrographia exhibits an unusual distinctiveness through its use of language, as it was printed in English, unlike many scientific books before it that had been circulated in Latin, such as English scientist William Harvey’s discovery of the circulation of blood through the heart and blood vessels in his book Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (Frankfurt, 1628).[9] Hooke’s choice to publish his book in English made it accessible to a wider range of people, sharing the advancements made in both literature and science during this time.
The preface suggests that Hooke wrote the book simply to document his findings and discoveries. He states that ‘the Science of Nature has been already too long made only a work of the Brain and the Fancy’.[10] He claims in this quotation that scientists should resort to the simple observation method from the ‘first Principles and Arts, on which they did begin’.[11] Robert Hooke’s belief that we should learn more about ‘the Sense’ and its usefulness, to further improve our health, coincided with the Scientific Revolution, and he added to the multitude of ‘fundamental transformations in people’s attitudes towards the natural world’.[12] With the use of microscopes, he explored the new invisible terrain that became open to people to view by the use of these instruments. Hooke’s thorough descriptions at the beginning of each observation made within Micrographia indicated that he believed the readers of his book should be well-informed about the material he was studying. Building on his belief in empirical observation, Hooke described various microscopes in his work. He detailed the construction and use of single-lens microscopes, noting their advantages and drawbacks.
In the book’s preface, he described making a single-lens microscope. It became well-known when Antonie van Leeuwenhoek (1632–1723) disclosed many microscopic observations in the late seventeenth and early eighteenth centuries. Hooke added material to construct a lamp that would provide enough lighting for microscopic observations, as he believed that natural lighting was mediocre in comparison.[13] Hooke found single-lens microscopes to have better quality than multi-lens ones but disliked their appearance and use, claiming they were ‘offensive to the eye’. He preferred compound microscopes for their ability to achieve greater magnification.[14] Hooke extensively used compound microscopes during his observations contained within Micrographia. Pairing a small lens near the specimen with a longer one by the eye created magnification. The focal lengths of both lenses, along with their specific combination, determined the degree of enlargement achieved.[15] These microscopes were an advancement of previous similar instruments, but they still required an enormous amount of skill to interpret and operate them accordingly. Hooke was among the first to observe Mucor, a type of micro fungus. This revelation sparked a chain reaction: improved microscopes, further microbial discoveries, and expanded insights into nature’s intricate design. Hooke’s work revolutionized microscopy, deepening our grasp of anatomy and the hidden world around us. His groundbreaking observation propelled scientific understanding forward, unveiling life’s microscopic marvels. As Gest notes, ‘Microscopy became the backbone of our understanding of the roles of microbes in the causation of infectious diseases and the recycling of chemical elements in the biosphere’.[16] Hooke believed that credible science required rigorous observation and experimentation. As he noted in Micrographia, ‘a sincere Hand, and a faithful Eye’ were essential for accurate scientific observation. This emphasis on meticulous observation underscored his approach to scientific inquiry.[17]
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Robert Hooke, Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon (London, 1667), plate XI: depictions of cells.
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Hooke recorded the structure of many organisms under the microscope, such as the stinger of a bee and the foot of a fly. However, one of his most prominent discoveries occurred when he coined the term ‘cell’. To produce this conclusion, he improved the design of the existing microscope in the same year, which led him to be able to observe cells under the microscope. Three lenses and a stage light formed this microscope’s core. Its design enhanced object visibility, allowing for more detailed observations under the instrument. This meant that Hooke could observe smaller materials under the microscope in greater detail, which allowed him to accurately describe the structure of the cell. In one drawing, he analysed a small piece of cork. He outlined its structure and walls and noted the space between them. He likened them to cells in a monastery, hence his term ‘cell’. To make the cork smooth and allow for observation, he had to cut it with a penknife. In other organisms, including trees and plants, he discovered a similar structure and noticed that some of the organisms had cells filled with a liquid (sap), while others did not. In the volume, he chronicles the piece of cork to appear ‘porous’ and similar ‘as those thin films of Wax in a Honey-comb’.[18] This description helped illustrate the cell structure he had discovered. Hooke observed that the cells in cork were so small that even the smallest atoms, imagined by Epicurus (341BC–270), could fit inside them.[19] He described these structures as ‘the Vessels of nutrition to the vastest body in the World’, laying the groundwork for what would become cell theory.[20] This discovery reshaped the history of cell theory, revolutionizing microscopy and empowering future scientists to redefine anatomy and pioneer breakthroughs in science and medicine. For example, in 1666, the Italian scientist Marcello Malpighi (1628–94) discovered red blood cells in the body.[21] This analysis would not have been possible without the earlier discovery of the cell. This revelation would have lasting impacts, centuries later.
Robert Hooke, Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon (London, 1667), plate XV, depicting nettles.
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Hooke observed a variety of plants as well as animals within his book, including nettles. When examining the ‘stinging points and juice of Nettles’, Hooke explains to the reader that because they are so well known, he will not even bother describing a Nettle.[22] The suddenness of the stinging pain experienced upon contact with a nettle fascinated Hooke, as well as the ‘angry and hard swellings and inflammations of the parts, such as will presently rise’.[23] He determined to find out why this happened. Thin, transparent, and arrowhead-shaped, the nettle’s ‘stinging points’ revealed themselves as hollow structures. Through a painful experiment, Hooke discovered that when he thrust his hand into the nettle, he felt the expected stinging pain. But when he pulled it back, he noticed that the ‘stinging points’ withdrew into the small, green bags to which they were connected. Hooke discovered that the bags were receptacles of an unknown liquid, which he suspected to be poisonous, and that the stinging points were simply syringes to transport this liquid. Hooke concluded that the syringes injected a poisonous liquid into the skin. It began to corrode and burn, causing a painful, throbbing sting like that of a nettle. He compared this discovery to his earlier study of the sting of a bee and a wasp, in which he found the result to be the same.
Robert Hooke, Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon (London, 1667), plate XXXI, depicting the ‘Shepherd Spider’.
Hooke also defines the ‘Shepherd’, or long-legged spider, for two reasons; it has only two eyes, placed on top of its head back-to-back from each other instead of multiple eyes, like other spiders. The eyes of this spider were like those of larger binocular creatures, containing an iris and a pupil, something that most other spiders do not have. Another peculiarity noted by Hooke was the length of this particular spider’s legs. He described that he measured each of them and found them to be up to sixteen times as long as their bodies. What Hooke had observed was a common cellar spider, more often known by the colloquial term ‘daddy long-legs’. He decided that the legs were like those of a crab, although the length was much longer in proportion to its body. Hooke illustrated the immense strength that the spider must possess, as it could support itself on its long legs and move them about quite easily.
Robert Hooke, Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon (London, 1667), plate XXXIV: a flea.
One of Hooke’s most eye-catching observations in Micrographia is of a flea. Robert Hooke outlines the strength and beauty of the flea in his observations, although he notes that the observational power of the microscope did not enable him to study the flea in much more detail, except through its legs. Hooke itemises how the legs of a flea are folded short within one another, but can suddenly spring out, engaging the entire strength of the small creature. It also has a pair of sharp, blade-like instruments, which presumably bite, pierce the skin, and suck an animal’s blood. Hooke identifies several additional components of the flea, but, deeming them insufficiently informative, he opts to omit their detailed discussion. Hooke’s largest illustration contained within the book is a drawing of the flea, which is a fold-out image of the animal. The illustration displays the labelled anatomy of the creature, and gives the reader much more intricacy than would ordinarily be possible.
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Robert Hooke remained a geometry lecturer at Gresham College until he died on 3 March 1703. He also attained a medical license for his early work in medicine and microscopy. He continued to have influence in the world, and his work, particularly Micrographia, played a pivotal role in the Scientific Revolution. As Brain argues, ‘The period marked a watershed moment and would become a precursor to modern science as we know it today’.[24] Micrographia’s ground-breaking observations and meticulous illustrations captivated scholars and the public alike, igniting widespread interest in microscopy and shaping future research. For example, Dutch scientist Antonie van Leeuwenhoek, who also studied microorganisms, was influenced by Hooke’s discoveries and later became the first person to observe bacteria using a microscope. Hooke’s discoveries in Micrographia advanced hypotheses concerning microbiology and helped other scientists in their discovery of microorganisms around the world. The volume also enabled other scientists to recognise their findings for what they were. Micrographia was very well received at the time of its publication because of its pioneering theories and application. The book captured the interest of many people and was reviewed by numerous intellectuals. One such review was by government official Samuel Pepys (1633–1703), who recorded staying up until 2:00 in the morning to continue reading the book, which he cited as ‘the most ingenious book that I ever read in my life’.[25] But some viewed such pursuits as a waste of time, considering his discoveries to have no impact on society. Even so, the book had huge influence after its publication and would contribute to the development of microscopy centuries afterwards. As Gest notes, ‘Micrographia was the first step to the development of fundamental theories, such as cell theory, and the refutation of spontaneous generation that developed two hundred years later’.[26] Hooke’s main aim in creating Micrographia was to enlighten people about the hidden world beyond their sight. This passion for knowledge and observation, clear in the book, makes it a unique and important scientific text today.
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Text: Ms Eleanor Mooney, Transition Year, Mount Anville Secondary School, Dublin.
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Sources
Anon, ‘The History of the Microscope Infographic’, Microscope World.
Bardell, David, ‘The Invention of the Microscope’, Bios, 75, no. 2 (May, 2004), 78–84.
Brain, Jessica, ‘The Scientific Revolution’, Historic UK.
Britannica, The Editors of Encyclopaedia, ‘Antonie van Leeuwenhoek’, Encyclopaedia Britannica.
Britannica, The Editors of Encyclopaedia, ‘Robert Hooke’, Encyclopaedia Britannica.
Diano, Carlo, ‘Epicurus’, Encyclopaedia Britannica.
Evans, James and Michael Wulf Friedlander, ‘astronomy’, Encyclopaedia Britannica.
Falkowski, Paul and Jo Marchant, ‘The Best Books on Microbes’, Five Books.
Gest, Howard, ‘The Discovery of Microorganisms by Robert Hooke and Antoni van Leeuwenhoek, Fellows of the Royal Society’, Notes and Records of the Royal Society of London, 58, no. 2 (May 2004), 187–201.
Green, Edna R., Susan Heyner Joshi and Kara Rogers, ‘biology’, Encyclopaedia Britannica.
Greenberg, Stephen J., ‘Hooke’s Books: influences around Robert Hooke’s Micrographia’, National Library of Medicine.
Hart-Davis, Adam, ‘The Best Books on Popular Science’, Five Books.
Hooke, Robert, Micrographia: or some physiological descriptions of minute bodies made by magnifying glasses with observations and inquiries thereupon (London, 1667).
Hunter, Michael, The image of restoration science: the frontispiece to Thomas Sprat’s History of the Royal Society (1667) (London and New York, 2017).
The Huntington Library, Art Museum, and Botanical Gardens, ‘Micrographia’, The Huntington.
Murphy, David, ‘Tighe, Richard’, Dictionary of Irish Biography.
National Geographic Society, ‘History of the Cell: Discovering the Cell’, National Geographic.
Neri, Janice, The insect and the image: visualizing nature in early modern Europe, 1500–1700 (Minneapolis and London, 2011).
Pugliese, Patri J., ‘Hooke, Robert (1635–1703)’, Oxford Dictionary of National Biography.
Ribatti, Domenico, ‘William Harvey and the discovery of the circulation of the blood’, Journal of Angiogenesis Research, 1, no. 3 (September 2009), 1–2.
Toffoletto, Ettore and Alfredo Riva, ‘Marcello Malpighi’, Encyclopaedia Britannica.
Wommer, Fernanda Gabriela Bitencourt, et al., ‘Retracting and rewriting Hooke’s Micrographia book for teaching history of science’, Journal of Biological Education, 52, no. 2 (April 2018), 155–165.
[1] Murphy, David, ‘Tighe, Richard’, Dictionary of Irish Biography.
[2] Edward Worth Library, Modern Catalogue entry for: Hooke, Robert, Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon (London, 1667).
[3] The Royal Society, ‘History of the Royal Society’, The Royal Society; Hunter, Michael, The image of restoration science: the frontispiece to Thomas Sprat’s History of the Royal Society (1667) (London and New York, 2017), pp 26 and 28.
[4] Pugliese, Patri J., ‘Hooke, Robert (1635–1703)’, Oxford Dictionary of National Biography.
[5] Ibid.
[6] Ibid.
[7] Hooke, Robert, Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon (London, 1665), title page.
[8] The Huntington Library, Art Museum, and Botanical Gardens, ‘Micrographia’, The Huntington.
[9] Hart-Davis, Adam, ‘The Best Books on Popular Science’, Five Books.
[10] Hooke, Robert, Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon (London, 1667), Sig. b1r.
[11] Ibid.
[12] Brain, Jessica, ‘The Scientific Revolution’, Historic UK.
[13] Bardell, David, ‘The Invention of the Microscope’, Bios, 75, no. 2 (May 2004), 83.
[14] Gest, Howard, ‘The Discovery of Microorganisms by Robert Hooke and Antoni van Leeuwenhoek, Fellows of the Royal Society’, Notes and Records of the Royal Society of London, 58, no. 2 (May 2004), 197.
[15] The Huntington Library, Art Museum, and Botanical Gardens, ‘Micrographia’, The Huntington.
[16] Gest, ‘The Discovery of Microorganisms’, 187.
[17] Hooke, Micrographia (London, 1667), Sig. a2v.
[18] Ibid., p. 113.
[19] Diano, Carlo, ‘Epicurus’, Encyclopaedia Britannica.
[20] Hooke, Micrographia (London, 1667) p. 114.
[21] Toffoletto, Ettore and Alfredo Riva, ‘Marcello Malpighi’, Encyclopaedia Britannica.
[22] Hooke, Micrographia (London, 1667), p. 142.
[23] Ibid.
[24] Brain, Jessica, ‘The Scientific Revolution’, Historic UK.
[25] Gest, ‘The Discovery of Microorganisms’, 189.
[26] Wommer, Fernanda Gabriela Bitencourt, et al., ‘Retracting and rewriting Hooke’s Micrographia book for teaching history of science’, Journal of Biological Education, 52, no. 2 (April 2018), 156.