Science in 18th Century England

J. H. Plumb

Earlier in the century the wealthy had plundered the Continent to fill their houses with Italian fireplaces, French furniture and tapestries. The cult of the exotic was still continued and in Horace Walpole and his friends took a disquieting turn towards the Gothic, but these things affected only a little the broad trend of English taste. Taste was dominated by an extremely refined sense of proportion which craftsman after craftsman, famous or unknown, struck like a note in music – clear, precise, concordant. The great masters were James Gibb, William Kent, and the brothers Adam in architecture; in furnishing, first Thomas Chippendale and then Sheraton. They immortalized themselves and their time.

Science has always been more international than art, and this is demonstrated again and again in the middle years of the eighteenth century, especially in the investigation of problems relating to the nature of oxygen and electricity, and it is difficult to disentangle the work of English from that of continental scholars. The greatest English scientist of the time was Henry Cavendish (1730-1800), the grandson of the second Duke of Devonshire, and he made contributions of the first magnitude to both the great problems of eighteenth-century science – the separation and identification of gases and the nature of electricity. Unfortunately Cavendish was extremely eccentric. He rarely spoke; sometimes he did, and sometimes he did not, communicate his discoveries to the Royal Society. Some of his best work remained unknown for a hundred years and Faraday had to discover independently much that he had done. Apart from Cavendish there is no one comparable to Joseph Priestley – a strange polymath. Priestley’s scientific work was done largely as an amusement, for he considered his philosophic, theological, and historical speculations to be his life-work upon which his claims to fame would be founded. He was a radical. He supported Wilkes, the American colonists, and the French Revolutionaries. His religious views were equally advanced. His notoriety was enormous, and many people, like Dr Johnson, regarded him as a menace to society. The Birmingham mob tore down his house and wrecked his laboratory. It would seem that Priestley had ample justification for his belief that he would be remembered principally as a philosopher. But, even in his own time, his experimental genius was building up a solid scientific reputation.

The work of our two most distinguished scientists – Priestley and Cavendish – rested, of course, upon the discoveries and methods of earlier workers. The Rev. Stephen Hales had invented, in 1727 or before, a satisfactory method of collecting gases, a fundamental step which made the investigations of Cavendish and Priestley possible. But Hales never seems to have investigated systematically the gases which he collected. The first person to do this was Joseph Black, the Professor of Chemistry at Glasgow. Black, too, was a man of genius, and he introduced for the first time quantitative methods, and brought strict and accurate measurements to chemistry. His methods and Hales’ apparatus led to the isolation and investigation of carbon dioxide, which he called ‘fixed air.’ The unique position which chemists had always given to atmospheric air was no longer tenable, and it was not long before the nature of air itself was being investigated. Progress was, however, very seriously retarded by the assumption that metals were compounds of metallic earth and a mysterious substance called phlogiston. Although this theory did not by any means meet all the known facts, its adherents clung to it with the tenacity of martyrs. When on 1 August 1774 Priestley isolated oxygen he shattered the phlogiston theory, but so great was his faith that he refused to believe his own experiments and elaborated the most extraordinary reasons to make his facts fit the phlogiston theory. But later in the year Priestley dined with Lavoisier, the great French chemist, who immediately realized the significance of Priestley’s discoveries. He shut himself up and worked fantastically hard until the following Easter, when he destroyed the phlogiston theory once and for all and established oxygen. He made no acknowledgement whatsoever to Priestley, who continued to hold his own theory in the face of all evidence until his death in 1804. Meanwhile, in monk-like seclusion, Cavendish absorbed these discoveries and carried them further. He broke down water into oxygen and hydrogen, and so destroyed another of the age-old ‘elements.’ For once, Cavendish conveyed his discovery to the Royal Society. He also isolated the rare gas – argon – from the atmosphere: but this he kept to himself.

In physics, as in chemistry, the most fundamental discovery of the century was made by Priestley, but, again, it was a Frenchman who gave the discovery its final precision. In 1766 Priestley discovered the Law of Inverse Squares, that the attraction or repulsion between two electric charges is inversely proportional to the square of the distance between them, which became the starting point for the more precise work of Coulomb. Cavendish, too, was interested in the properties of electricity, and his investigations were of outstanding brilliance and absolutely fundamental, but such vital conceptions as potential and specific inductive capacity he kept to himself. Faraday rediscovered them in the middle of the next century.

But electricity was also a fashionable game. Louis XV witnessed the administration of an electric shock to a line of monks a mile long and was convulsed with laughter when they all leapt into the air. Public demonstrations of the powers of electricity became exceedingly popular and profitable. To see brandy ignited by a spark shooting from a man’s finger became one of the wonders of the age. Wesley became a firm believer in electricity’s curative powers because he regarded it as a kind of élan vital, and he warmly recommended intense and prolonged electric shocks for a wide range of diseases from malaria to hysteria. Other amateurs preferred to experiment on themselves first and a miscellaneous crop of discoveries followed – the Leyden jar, Galvani’s frogs’ legs, and the great Anglo-American contribution – Benjamin Franklin’s lightning conductors which George III had installed in Buckingham Palace as soon as he bought it.

There was a deepening curiosity about nature, about mankind, about society, and its historic past. In all studies there was greater precision, and an increased reliance on observation, a growing detachment from the intellectual attitudes of the past. There had been great works of historical scholarship before Gibbon’s Decline and Fall of the Roman Empire (1776-88), but few historians had dared to display Gibbon’s confident, self-reliant judgement, so precisely detached from traditional beliefs. There is the same unwillingness to accept popular superstitions, and popular beliefs, in Adam Smith’s Enquiry into the Wealth of Nations (1776), which established political economy as a social science, whereas before it had been little better than ill-substantiated special pleading. Apart from such outstanding men as Gibbon and Smith, there were scores of other men of great ability, exploring or indicating new worlds of knowledge and understanding. And yet this wealth of science and art and scholarship was produced by a population far less than that of present-day London.

Professor J. H. Plumb, England in the Eighteenth Century (1714 – 1815), Volume 7 of The Pelican History of England, Penguin Books, 1950 pp.101-104.

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