Silvanus Phillips Thompson

“ He must measure, he must weigh, in order that he might go on to calculate. ’The first step,' he wrote, 'toward numerical reckoning of properties of matter ... is the discovery of a continuously varying action of some kind, and the means of observing it definitely, and measuring it in terms of some arbitrary unit or scale division. But more is necessary to complete the science of measurement in any department, and that is the fixing on something absolutely definite as the unit of reckoning.' It was in this spirit that Thomson approached the subject of the transformation of heat. ”

“ He strove whole-heartedly through life to reach a great comprehensive theory of matter. If he failed to find in the equations of dynamics an adequate and necessary foundation for the theories of electricity and magnetism, or to assign a dynamical constitution to the luminiferous ether, it is because the physical nature of electricity and of ether is probably more fundamental than that of matter itself. ”

“ The utilisation of science for practical ends was Thomson's ambition through life. 'There cannot,' he said in a lecture to the Institution of Civil Engineers in May 1883, 'be a greater mistake than that of looking superciliously upon practical applications of science. ”

“ Hitherto Thomson's work had lain mainly in pure science ; hut while still engaged on his thermodynamic studies, he was drawn toward the first of those practical applications that made him famous. Early in 1853 he had communicated to the Glasgow Philosophical Society a paper 'On Transient Electric Currents,' in which he investigated mathematically the discharge of a Leyden jar through circuits possessing self-induction as well as resistance. He founded his solution on the equation of energy, ingeniously building up the differential equation and then finding the integral. ”

“ Kindly hearted and exceptionally modest, he carried through life intense love of truth and insatiable desire for the advancement of natural knowledge. His high ideals led him to underrate his achievements. ”

“ Further, by a most ingenious use of the integrating factor to solve the differential equation for the quantity of heat needed to alter the volume and temperature of unit mass of the working substance, he gave precise mathematical proof of the theorem that the efficiency of the perfect engine working between given temperatures is inversely proportional to the absolute temperature. ”

“ Further than this, adopting a mechanical integrator, the device of his ingenious brother, James Thomson, he invented a harmonic analyser — the first of its kind — capable not only of analysing any given periodic curve such as the tidal records and exhibiting the values of the coefficients of the various terms of the Fourier series, but also of solving differential equations of any order.
Wave problems always had a fascination for Thomson, and he was familiar with the work of the mathematicians Poisson and Cauchy on the propagation of wave-motion. ”

“ Together they studied the theory of waves, 'which he loved,' says Helmholtz, 'to treat as a race between us.' On calm days he and Helmholtz experimented on the rate at which the smallest ripples on the surface of the water were propagated. Almost the last publications of Lord Kelvin were a series of papers on 'Deep Sea Ship Waves,' communicated between 1904 and 1907 to the Royal Society of Edinburgh. He also gave much attention to the problems of gyrostatics, and devised many forms of gyrostat to elucidate the problems of kinetic stability. ”

“ With the slenderest material resources and most inadequate room, he created a laboratory of physics, the first of its kind in Great Britain, where he worked incessantly, gathering around him a band of enthusiastic students to collaborate in pioneering researches in electric measurement and in the investigation of the electro-dynamic and thermoelectric properties of matter. ”

“ He loved in later life to talk of his student days and of his teachers, William Ramsay, Lushington, Thomas Thomson, Meikleham, and John Pringle Nichol. He early made his mark in mathematics and physical science ; and in 1840 won the university medal for a remarkable essay, 'On the Figure of the Earth.' During his fifth year as a student at Glasgow (1839-40) he received a notable impulse toward physics from the lectures of Nichol and of David Thomson, who temporarily took the classes in natural philosophy during the illness of Meikleham. ”

“ The first part of the first volume of Thomson and Tait's 'Treatise on Natural Philosophy' was published in 1867, the second part only in 1874. No more was published, though the second edition of the first part was considerably enlarged. The book had the effect of revolutionising the teaching of natural philosophy.
Thomson's contributions to the theory of elasticity are no less important than those he made to other branches of physics. In 1867 he communicated to the Royal Society of Edinburgh a masterly paper 'On Vortex Atoms' ”

“ In 1876 he visited America, bringing back with him a pair of Graham Bell's earliest experimental telephones. He was president of the mathematical and physical section of the British Association of that year at Glasgow. In the winter of 1860-1 Thomson had met with a severe accident. He fell on the ice when curling at Largs, and broke his thigh. The accident left him with a slight limp for the rest of his life.
Meanwhile much beside the submarine cable occupied Thomson's fertile mind, and his researches were incessant. In 1859-60 he was studying atmospheric electricity. ”

“ THOMSON, Sir WILLIAM, first Baron Kelvin of Largs (1824–1907) , man of science and inventor, born on 26 June 1824 in College Square East, Belfast, was second son and fourth child of James Thomson (1786-1849) [q. v.] , professor of mathematics in the Royal Academical Institution of Belfast, by his wife Margaret, eldest daughter of William Gardiner of Glasgow. The elder brother, James (1822-1892) [q. v.] , was professor of engineering, first in Belfast, then in Glasgow. When William was six years old his mother died, and the father himself taught the boys, who never went to school. ”

“ Honours fell thickly on Thomson in his later life. He was thrice offered and thrice declined the Cavendish professorship of physics at Cambridge. He had been made a fellow of the Royal Society in 1851, and in 1883 had been awarded the Copley medal. He was president from 1890 to 1894. He was raised to the peerage in 1892 under the style and title of Baron Kelvin of Largs in the county of Ayr. On 15-17 June 1896 the jubilee of his Glasgow professorship was impressively celebrated by both the town and university m the presence of guests who included the chief men of science of the world. ”

“ In the summer of 1855, while they stayed at Kreuznach, Thomson sent to Helmholtz, whose acquaintance he desired to make, an invitation to come to England in September to attend the 'British Association meeting at Glasgow. On 29 July Helmholtz arrived at Kreuznach to make Thomson's acquaintance before his journey to England. On 6 August Hebnholtz wrote to his wife of the deep impression that Thomson, 'one of the first mathematical physicists of Europe,' made on him. ”

“ Thomson at twenty-one years had gained experience in three universities — Glasgow, Cambridge, and Paris—had published a dozen original papers, and had thus established for himself a reputation in mathematical physics. In 1846, at twenty-two, he became professor of natural philosophy in Glasgow on the death of Meikle ham. ”

“ He showed that vortex rings (like smokerings in air) in a perfect medium are stable, and that in many respects they possess qualities essential to the properties of material atoms — permanence, elasticity, and power to act on one another through the medium at a distance. The different kinds of atoms known to the chemist as elements were to be regarded as vortices of different degrees of complexity. The vortex-atom theory was linked to Ms other important researches on gyrostatic problems. ”