Lord Kelvin

For fifty-three years, the most famous scientist in the British Empire worked in a single Glasgow laboratory. William Thomson — Lord Kelvin — was appointed to the University of Glasgow’s chair of natural philosophy at the age of twenty-two, and never left it. He put absolute zero on the map, helped lay down the laws of thermodynamics, made the transatlantic telegraph work, and grew rich and titled on the strength of his inventions. He took his very name from the little river that ran past his laboratory windows — and every thermometer in science still bears it.

This page tells his story: the boy prodigy at the university, the chair he won at twenty-two, his measure of heat and cold, the great cable, his career as an inventor, the peerage that made him Lord Kelvin, and the errors of his old age.

A boy at the university

He was not, by birth, a Glaswegian at all. William Thomson was born in Belfast in 1824, the son of James Thomson, a gifted mathematician; and when, in 1832, his father was appointed professor of mathematics at the University of Glasgow, the family moved to the city that would be William’s home for the rest of his life. The boy was prodigiously clever, and entered the university as a matriculated student at the astonishing age of ten. From Glasgow he went on to Cambridge, graduating with the highest honours, and then to Paris, where he worked in the laboratory of the physicist Henri-Victor Regnault and sharpened his grasp of the experimental side of science. By his early twenties he had already published a dozen scientific papers.

The chair at twenty-two

In 1846 the University of Glasgow needed a new professor of natural philosophy — what we would now call physics — and the post went to William Thomson, then just twenty-two years old. It was the beginning of an extraordinary tenure: he would hold the Glasgow chair for fifty-three years, until his retirement in 1899, turning down repeated offers from Cambridge and elsewhere to remain loyal to the university where he had grown up — the institution where, decades earlier, James Watt had conceived his improved steam engine. There he created what is generally reckoned the first physics teaching laboratory in Britain, a place where students did not merely listen to lectures but measured, experimented and tested for themselves. From that Glasgow base, Thomson would reshape the physical science of his age.

The measure of heat

Thomson’s deepest work was on heat. Only two years into his professorship, in 1848, he proposed an ‘absolute’ scale of temperature — one that did not depend on the properties of any particular substance such as mercury, but on the fundamental physics of heat itself. Its zero was the coldest temperature that could possibly exist, absolute zero, about minus 273 degrees Celsius; and that scale, measured in units now called kelvins, is the one science uses to this day. He went on, working alongside the English physicist James Joule, to help establish the laws of thermodynamics, formulating the great second law — that heat will not of its own accord flow from a colder body to a hotter one. In doing so he helped turn the study of heat and energy into an exact science.

The Atlantic cable

It was not pure science, though, that made Thomson a household name, but a feat of engineering: the laying of the first telegraph cable across the Atlantic Ocean, to join Europe and America. The early attempts were beset by failure, and Thomson’s contribution was decisive. He devised the instruments that made long-distance submarine telegraphy possible — above all the mirror galvanometer, an exquisitely sensitive receiver able to detect the faint signals that crept across two thousand miles of ocean cable, and later the siphon recorder. When the cable at last succeeded in 1866, Thomson was the hero of the hour, and was knighted by Queen Victoria for his part in binding the continents together.

The inventor & the yacht

The cable made Thomson not only famous but wealthy. He patented some seventy inventions over his career, and his partnership in the engineering firms that tested and manufactured cables brought him a fortune. Much of his inventive genius was turned to the sea: he devised a greatly improved mariner’s compass, adopted by the Royal Navy, a mechanical sounding machine for measuring the depth of water, and a remarkable analogue machine for predicting the tides. With his riches he bought a large schooner yacht, the Lalla Rookh, which he used as a floating laboratory, testing his instruments at sea and entertaining on a lavish scale. Few scientists of any age have so successfully turned discovery into hard cash.

Baron Kelvin of Largs

Honours were heaped upon him. He was elected President of the Royal Society, showered with medals and honorary degrees, and in 1892 raised to the peerage — the first British scientist ever to be so honoured, and the first to sit in the House of Lords. For his title he looked to Glasgow: he became Baron Kelvin of Largs, taking the name Kelvin from the River Kelvin, the little stream that flows through Kelvingrove park, past the University where he had spent his whole scientific life, and Largs from the Ayrshire coast where he had his country estate. It was a fitting choice, binding the greatest scientist of the Victorian age forever to the city and the river that had made him.

The sage who said no

For all his genius, Kelvin’s last years saw him increasingly at odds with the new science emerging around him. He is remembered, a little unfairly, for a series of confident pronouncements that time proved wrong: that heavier-than-air flying machines were impossible, that radio had no future, that X-rays would prove a hoax. His celebrated estimate of the age of the Earth, worked out from its cooling, fell far short of the truth — for Kelvin could not have known of the radioactivity that keeps the planet warm. These were the errors of a great man at the end of a long life, and they do not diminish his achievement. When he died at Largs in 1907, he was buried in Westminster Abbey, close by the tomb of Sir Isaac Newton — a resting place that measured the esteem in which his age had held him. In Kelvingrove park his statue sits in view of the university, and the river, that bear his name.

A life in dates