Robert Boyle and the Birth of Modern Chemistry
Robert Boyle, a prominent figure in the 17th century, is often credited with the transition of alchemy into modern chemistry through his rigorous experimental approach. Born into the Irish aristocracy, Boyle was a child prodigy who studied influential scientific ideas from thinkers like Galileo and Descartes. He became a key member of the Invisible College, a precursor to the Royal Society, and was instrumental in advancing scientific experimentation, particularly through the invention of an effective air pump. His notable discoveries included demonstrating the inverse relationship between gas pressure and volume, now known as Boyle's Law, and conducting experiments that highlighted the significance of air in combustion and respiration.
Boyle's influential work, "The Sceptical Chymist," challenged traditional notions of elements and emphasized the importance of observations grounded in experimental evidence. Although some modern scholars debate Boyle's role as the founder of modern chemistry, his contributions to both qualitative and quantitative analysis and his introduction of new techniques in the laboratory laid the groundwork for future scientific inquiry. Additionally, Boyle's deep religious convictions and efforts to reconcile science with faith further enriched his legacy, making him a pivotal figure not only in chemistry but also in the broader dialogue between science and spirituality.
Robert Boyle and the Birth of Modern Chemistry
Locale England
Date 1660-1692
Often called the “father of modern chemistry,” Robert Boyle discovered the inverse relationship between the pressure and volume of a gas. He devised influential definitions of a chemical element, compound, and reaction. He also used his corpuscular philosophy, an atomic theory of matter, to explain his experimental results.
Key Figures
Robert Boyle (1627-1691), Irish chemist and physicistRobert Hooke (1635-1703), English physicistRené Descartes (1596-1650), French philosopher, physicist, and mathematicianPierre Gassendi (1592-1655), French priest and atomistOtto von Guericke (1602-1686), German physicist who invented the air pumpEdmé Mariotte (1620-1684), French priest and physicistJohn Mayow (1641-1679), English physiologistRichard Lower (1631-1691), English physician
Summary of Event
For chemistry to become a modern science, old ideas had to be abandoned and new ideas introduced. During the seventeenth century the scientist most responsible for the transformation of alchemy into chemistry was Robert Boyle. Unlike many natural philosophers of the Scientific Revolution, who viewed chemistry as either a pseudoscience or a practical craft, Boyle treated chemistry as worthy of a rigorous experimental approach.
Born into the aristocracy in Ireland, Boyle had been a child prodigy who developed his intellectual skills at Eton and, with a tutor, on a tour throughout Europe. He studied the new scientific ideas of such natural philosophers as Galileo, Pierre Gassendi, and René Descartes . After his return to England in the mid-1640’, he devoted more and more of his time to scientific studies. He became a member of a group of science enthusiasts called the Invisible College, which was the forerunner of the Royal Society, an important institution in Boyle’s later career.
While at Oxford in the late 1650’, Boyle learned of Otto von Guericke’s demonstration in Magdeburg, Germany, of the tremendous pressure of the atmosphere. Guericke used his invention, an air pump, to suck the air out of two metal hemispheres fitted together along a circumferential flange. Several teams of horses were unable to disjoin them, but as soon as air was reintroduced into the joined hemispheres, they readily fell apart. With the help of a talented assistant, Robert Hooke, Boyle constructed an air pump that was much more effective than the one used in Germany. Indeed, so effective was this pump at evacuating experimental vessels that vacuum Boylianum (“Boylean vacuum”) became a standard scientific designation.
For two years Boyle used his air pump to perform a variety of experiments. He demonstrated that a feather and a lump of lead fell at the same velocity in a vacuum, that a clock’s ticking was silent in a vacuum, and that electrical and magnetic attraction and repulsion remained undiminished in a vacuum. Birds and mice did not long survive in a vacuum, and a candle flame sputtered out when deprived of air. Boyle published an account of his research in his first scientific book, New Experiments Physico-Mechanicall, Touching the Spring of the Air and Its Effects (1660).
Because of Boyle’s belief that he had created a vacuum, a controversial notion at the time, his book provoked criticisms from Aristotelians and Cartesians who believed that voided spaces were impossible in a universe completely filled with matter. In response to a particular critic, the Jesuit Franciscus Linus, Boyle devised his most famous experiment, an account of which he published in the second edition of his book in 1662. Using a seventeen-foot-long J-shaped glass tube sealed at the short end, Boyle trapped air in the sealed end by pouring mercury into the long open tube. He discovered that, when he doubled the weight of the mercury in the long tube, the volume of the trapped air was halved. This discovery of the inverse relationship between a gas’s pressure and volume came to be called Boyle’s Law in English-speaking countries. It was called Mariotte’s Law in continental European countries, because, in 1676, Edmé Mariotte, independently of Boyle, discovered this inverse relationship with the important provision that the temperature during measurements had to be kept constant.
As a corpuscularian philosopher, Boyle tried to explain the results of his experiments mechanically, but his corpuscles were not the same as Gassendi’s or Descartes’. Boyle’s corpuscles had size, shape, and mobility, though he was cautious in using these theoretical entities to account for experimental phenomena. For example, in the case of the compressibility of air, he proposed that air corpuscles might be like tiny coiled springs, but since air was also involved in chemical processes such as combustion, Boyle believed that air was a peculiar substance, an elastic fluid teaming with foreign materials.
Boyle’s theoretical ideas made their appearance when he published The Sceptical Chymist (1661, rev. 1679). This work, often called his masterpiece, was written as a dialogue among spokespeople holding different views about the nature of chemistry. However, it was clearly an attack on the ancient Aristotelian notion that all matter is composed of four elements, earth, water, air, and fire, and a repudiation of the Renaissance view that all chemical phenomena can be explained through the three principles of salt, mercury, and sulfur.
Unwilling to rely on previous authorities, the “sceptical” Boyle emphasized that chemical ideas had to be grounded in observations and experiments. For him, no reason existed for limiting the elements to three or four, since an element was basically a substance that could not be broken down into simpler substances. These elemental substances, which are capable of combinations in various compounds, were behind all material things and their changes. Though Boyle’s “operational definition” of elements became influential, however, he found it difficult in practice to determine whether particular substances were simple or complex.
Not only did Boyle contribute to physical and theoretical chemistry, he also helped found qualitative and quantitative analysis. For example, he developed identification tests to make sure he was using pure materials. Gold was pure if it had the correct specific gravity and dissolved in aqua regia (a mixture of hydrochloric and nitric acids) but not in aqua fortis (nitric acid alone). He also used precipitates, solubility, and the colors of substances in flames as analytical tools. He was especially fascinated with color indicators as a way to distinguish acidic, alkaline, or neutral substances. He discovered that a blue plant material, “syrup of violets,” turned red in acids, green in alkalis, and remained unchanged in neutral solutions.
Throughout the history of chemistry, researchers used fire to study chemical changes. Boyle knew that combustion stopped in the absence of air, but he also knew that gunpowder burned under water (he thought that the saltpeter in gunpowder acted as an air substitute). Like other researchers, Boyle also observed that, when metals were heated in air, they formed a powdery substance (a “calx”) that was heavier than the original metal. He explained the weight increase as due to the addition of “igneous corpuscles,” but a contemporary, John Mayow, was closer to the truth when he speculated that a substance common to air and saltpeter (now known to be oxygen) might be the cause of combustion.
Like other experimenters, Boyle discovered a connection between combustion and respiration, since he observed that a burning candle and a breathing mouse both reduced the volume of air. Mayow believed that the blood in the lungs absorbed the “combustive principle” from the air and distributed it throughout the body. Another contemporary of Boyle, Richard Lower, discovered that air could change dark venous blood to bright red arterial blood. Besides blood, Boyle was also interested in urine, from which he prepared phosphorus, whose luminosity in air intrigued him (he initiated the practice of storing phosphorus under water). Although Boyle failed to find the true role that air played in respiration and in the combustion of phosphorus, his emphasis on methodical experimentation served as an exemplar for those eighteenth century scientists who would eventually make these discoveries.
Significance
Victorian writers bestowed on Boyle the epithet “father of modern chemistry” because of his realization that chemistry was worthy of study for its own sake and not just because of its usefulness to medicine and metallurgy. He also showed those natural philosophers who denigrated chemistry as an occult science that chemists, through rigorous experiments, could make important discoveries every bit as objective as those of physicists. On the other hand, some twentieth century scholars have questioned Boyle’s traditional role as modern chemistry’s founder. They emphasize that what Boyle meant by an element is not what modern chemists mean by it. For example, Boyle did not think that metals were elements, but the periodic table contains many metals that are genuine elements. Furthermore, Boyle did not really abandon alchemy, since he believed in its central doctrine, transmutation. He was so convinced that lead could be transformed into gold that he campaigned against an old royal decree forbidding transmutation research.
Despite the caveats of modern scholars, more chemical discoveries and theoretical ideas found in Boyle’s voluminous writings have become part of modern chemistry than the work of any of his contemporaries. The air pump he invented has been called “the Scientific Revolution’s greatest fact-making machine,” and Boyle’s experimental studies became models of the most productive way to do science. As an advocate of the experimental philosophy, he was one of the most influential members of the Royal Society, though he declined its presidency over a personal scruple about taking oaths. Though praised by physicists, Boyle saw himself above all as a chemist, and in his development of new techniques and control experiments, he had a great influence on the modern scientific research laboratory.
For his contemporaries, Boyle was the preeminent mechanical philosopher in England. He trained some important scientists, including Robert Hooke, Denis Papin (the inventor of a forerunner of the pressure cooker), and Johann Joachim Becher, an influential German chemist. During his lifetime, Boyle was also honored for his writings on natural theology. Deeply religious, he considered himself a “priest of Nature,” and in his will he left substantial funds to found the Boyle Lectures for the Defense of Christianity Against Its Enemies. These lectures, which have been given for over three centuries, symbolize the lasting significance of Boyle not only to scientists but also to all human beings trying to reconcile their search for meaning in life with the worldview created by modern science.
Bibliography
Brock, William H. The Chemical Tree: A History of Chemistry. New York: Norton, 2000. This reissue of a book originally published in England as The Fontana History of Chemistry contains an analysis of Boyle’s role in the origin of modern chemistry in chapter 3, “The Sceptical Chymist.” A forty-page bibliographical essay and an index.
Hall, Marie Boas. Robert Boyle and Seventeenth-Century Chemistry. New York: Krause, 1968. This American edition of a work published by Cambridge University Press in 1958 uses Boyle’s experimental work and theoretical ideas to investigate the nature of seventeenth century chemistry and the part it played in the ongoing Scientific Revolution. Bibliography and index.
Hunter, Michael, ed. Robert Boyle Reconsidered. New York: Cambridge University Press, 1994. This collection of studies includes analyses of Boyle’s experimental methods, his philosophical viewpoint, and his relationship to alchemy. Also includes a survey of Boylean historiography.
Maddison, R. E. W. The Life of the Honourable Robert Boyle, F.R.S. New York: Barnes and Noble Books, 1969. This narrative of Boyle’s life makes use of more accurate texts than earlier biographies, situates Boyle in his historical context, and shows how he sought to reconcile chemistry and the mechanical philosophy. Index.
Shapin, Steven, and Simon Schaffer. Leviathan and the Air Pump: Hobbes, Boyle, and the Experimental Life. Princeton, N.J.: Princeton University Press, 1985. The authors interpret Boyle’s work in the context of seventeenth century society and through the controversy between Hobbes and Boyle over the causal structure of nature. Extensive references to primary and secondary sources and an index.
Strathern, Paul. Mendeleyev’s Dream: The Quest for the Elements. New York: Berkeley Books, 2000. This popular thematic history of chemistry analyzes Boyle’s work in chapter 7, “A Born-again Science.” An annotated “further reading” section and an index.