Robert Boyle

Robert Boyle (1627–1691) was an Anglo-Irish natural philosopher whose experiments helped turn chemistry into a discipline of its own. Working in the scientific ferment of seventeenth-century England, he is usually regarded as the first modern chemist and one of the pioneers of experimental method. He is best known today for the law describing how the volume of a gas changes inversely with its pressure, but his wider importance lies in insisting that claims about matter be tested rather than inherited from authority.

Boyle was born at Lismore Castle in County Waterford, the fourteenth child of Richard Boyle, the first Earl of Cork, and his second wife, Catherine Fenton. His family provided an excellent education: he learned Latin, Greek and French as a child, and after his mother's death he was sent to Eton. At fifteen he travelled on the Continent with a French tutor, spending time in Geneva and Italy, where in 1641 he studied the paradoxes of Galileo, who died the following year. He returned to England in 1644 with a firm interest in research. His inheritance from his father gave him the financial independence to fund his own laboratory and experiments, which makes him a model of the gentleman scientist of his era.

Boyle joined the researchers known as the Invisible College, who met in London and Oxford to pursue the 'new philosophy'. After an unproductive period in Ireland, he settled in Oxford in 1654, where he worked with Robert Hooke to improve the air pump devised by Otto von Guericke. The resulting machine let him study the properties of air, and his 1660 book New Experiments Physico-Mechanicall, Touching the Spring of the Air and its Effects reported the results. While answering objections from the Jesuit Francis Line, he stated the relationship between a gas's volume and pressure that bears his name in England and Boyle-Mariotte on the Continent. Henry Power had formulated it first, in 1661, and Boyle later attributed a reference to the wrong author, so the credit is more shared than the name suggests.

In chemistry, The Sceptical Chymist challenged the doctrine of four Aristotelian elements and the alchemists' three principles of sulphur, mercury and salt. Boyle argued that substances should be defined by what experiments reveal about their composition, and proposed an operational notion of an element as a substance that cannot be broken down into simpler ones by known chemical means. He also discovered acid-base indicators and, with Hooke, formulated in 1659 the law governing the behaviour of springs. As a devout Anglican theologian, he left funds in his will for the Boyle Lectures, intended to defend Christianity against atheism.

His influence was lasting. The Invisible College became the Royal Society in 1663, and Boyle, a member of its council, became a model of the independent scientist. He valued knowledge for its own sake without neglecting practical uses, and his list of twenty-four possible inventions, nearly all of which have since come true, reflects his confidence in technical progress. He died in London in 1691, a week after his sister Katherine, with whom he had shared work and ideas for years.