Robert Boyle, Anglo-Irish natural philosopher, theological writer, chemist, physicist, inventor and a preeminent figure of 17th-century intellectual culture, dies on December 31, 1691, in London.

Boyle is born on January 25, 1627, at Lismore Castle, in County Waterford. At age eight, he begins his formal education at Eton College, where his studious nature quickly becomes apparent. In 1639 he and his brother Francis embark on a grand tour of the continent together with their tutor Isaac Marcombes. In 1642, owing to the Irish rebellion, Francis returns home while Robert remains with his tutor in Geneva and pursues further studies.

Boyle returns to England in 1644, where he takes up residence at his hereditary estate of Stalbridge in Dorset. There he begins a literary career writing ethical and devotional tracts, some of which employ stylistic and rhetorical models drawn from French popular literature, especially romance writings. In 1649 he begins investigating nature via scientific experimentation. From 1647 until the mid-1650s, he remains in close contact with a group of natural philosophers and social reformers gathered around the intelligencer Samuel Hartlib. This group, the Hartlib Circle, includes several chemists who heighten his interest in experimental chemistry.

Boyle spends much of 1652–1654 in Ireland overseeing his hereditary lands and performing some anatomic dissections. In 1654 he is invited to Oxford, and he takes up residence at the university until 1668. In Oxford he is exposed to the latest developments in natural philosophy and becomes associated with a group of notable natural philosophers and physicians, including John Wilkins, Christopher Wren, and John Locke. These individuals, together with a few others, form the “Experimental Philosophy Club.” Much of Boyle’s best known work dates from this period.

In 1659 Boyle and Robert Hooke, the clever inventor and subsequent curator of experiments for the Royal Society, complete the construction of their famous air pump and use it to study pneumatics. Their resultant discoveries regarding air pressure and the vacuum appear in Boyle’s first scientific publication, New Experiments Physico-Mechanicall, Touching the Spring of the Air and Its Effects (1660). Boyle and Hooke discover several physical characteristics of air, including its role in combustion, respiration, and the transmission of sound. One of their findings, published in 1662, later becomes known as “Boyle’s law.” This law expresses the inverse relationship that exists between the pressure and volume of a gas, and it is determined by measuring the volume occupied by a constant quantity of air when compressed by differing weights of mercury.

Among Boyle’s most influential writings are The Sceptical Chymist (1661), which assails the then-current Aristotelian and especially Paracelsian notions about the composition of matter and methods of chemical analysis, and the Origine of Formes and Qualities (1666), which uses chemical phenomena to support the corpuscularian hypothesis. He argues so strongly for the need of applying the principles and methods of chemistry to the study of the natural world and to medicine that he later gains the appellation of the “father of chemistry.”

Boyle is a devout and pious Anglican who keenly champions his faith. He sponsors educational and missionary activities and writes a number of theological treatises. He is deeply concerned about the widespread perception that irreligion and atheism are on the rise, and he strives to demonstrate ways in which science and religion are mutually supportive. For Boyle, studying nature as a product of God’s handiwork is an inherently religious duty. He argues that this method of study would, in return, illuminate God’s omnipresence and goodness, thereby enhancing a scientist’s understanding of the divine. The Christian Virtuoso (1690) summarizes these views and may be seen as a manifesto of his own life as the model of a Christian scientist.

In 1668 Boyle leaves Oxford and takes up residence with his sister Katherine Jones, Vicountess Ranelagh, in her house on Pall Mall in London. There he sets up an active laboratory, employs assistants, receives visitors, and publishes at least one book nearly every year. Living in London also provides him the opportunity to participate actively in the Royal Society.

Boyle is a genial man who achieves both national and international renown during his lifetime. He is offered the presidency of the Royal Society and the episcopacy but declines both. Throughout his adult life, he is sickly, suffering from weak eyes and hands, recurring illnesses, and one or more strokes. He dies at age 64 on December 31, 1691, after a short illness exacerbated by his grief over Katherine’s death a week earlier. He leaves his papers to the Royal Society and a bequest for establishing a series of lectures in defense of Christianity. These lectures, now known as the Boyle Lectures, continue to this day.