🇮🇪Robert
Boyle

Robert Boyle was the fourteenth child of the Earl of Cork, one of the wealthiest men in the British Isles, and he spent his considerable inheritance on air pumps. The device he and his assistant Robert Hooke built in 1659 — capable of evacuating a glass vessel to near-vacuum — was the finest scientific instrument of its age, and the experiments Boyle conducted with it constituted a systematic assault on two thousand years of natural philosophy. He demonstrated that sound could not travel through a vacuum, that a candle could not burn without air, that a small animal placed in the evacuated vessel would die, and — most consequentially for physics — that the pressure of a confined gas varies inversely with its volume when temperature is held constant. This relationship, published in 1662, is still called Boyle's Law, and it remains in every introductory physics and chemistry textbook in the world.

Robert Boyle was born on January 25, 1627, at Lismore Castle in County Waterford, Ireland. He was educated at Eton and then spent several years touring Europe with a tutor, during which he read Galileo's Dialogue Concerning the Two Chief World Systems and was permanently converted to the new mechanical philosophy. He settled in Oxford in 1654, where he assembled a circle of experimentally minded natural philosophers that included Hooke, Christopher Wren, and John Wilkins, many of whom would become founding members of the Royal Society when it was chartered in 1660. Boyle himself was offered the presidency of the Society but declined, as he declined a peerage, unwilling to take oaths that might conflict with his religious convictions.

In 1661 Boyle published The Sceptical Chymist, the book that historians of science point to as the founding document of modern chemistry. Its argument was double-edged: against the Aristotelian four-element theory (earth, water, fire, air) and against the alchemists' three principles (mercury, sulfur, salt). Boyle proposed instead that matter was composed of minute corpuscles — particles — and that chemical elements were simply those substances that could not be further decomposed. This corpuscular theory anticipated atomic theory by more than a century, and Boyle's operational definition of the element — the starting point from which chemists must work — anticipated Lavoisier's by over a hundred and twenty-five years. Boyle did not succeed in identifying many true elements, but he established the question that chemistry would spend two centuries answering.

Boyle was also among the first to conduct chemistry as a public, reproducible enterprise. He believed that experiments should be witnessed, described precisely enough to be replicated, and published — a philosophy now so foundational to science that it is invisible, like water to a fish. He wrote prolifically: on the nature of colors, on cold, on electricity and magnetism, on the specific gravity of solids and liquids, on the possibility of a phosphorescent substance — which he identified and described — and on theology. He was deeply and genuinely religious, believed that the study of nature was a form of worship, and left a bequest funding the Boyle Lectures, an annual series defending Christianity against unbelief, which continued for decades after his death.

He moved to London in 1668 to live with his sister Lady Ranelagh, and remained there until his death on December 31, 1691, just a week after her own. He had never married, dedicating himself entirely to his experiments and his writing. He left behind a body of work that established experimental methodology as the core of natural philosophy, defined the conceptual vocabulary that chemistry would use for two centuries, and produced the gas law that every student of science encounters in their first year of study. He was sixty-four years old, and the discipline he had helped create was barely beginning.