cian to the Marquis of Lansdowne, whom he accompanied to Harrogate and Bowood.
In his twenty-sixth year, on the death of Dr. Thomas Percival [q. v.], Roget was appointed in 1805 physician to the infirmary at Manchester, and he became one of the founders of the Manchester medical school. In the spring of 1806 he gave a course of lectures on physiology to the pupils at the infirmary. In November 1806 he accepted the appointment of private secretary to Charles, viscount Howick (afterwards Earl Grey), then foreign secretary; but, disliking the duties, he resigned in a month and returned to Manchester. While in London he had attended some of Abernethy's lectures at St. Bartholomew's Hospital. In 1807 he delivered a popular course of lectures on the physiology of the animal kingdom at the rooms of the Manchester Philosophical and Literary Society, of which he was a vice-president. In October 1808 he resigned his post at the infirmary and migrated to London. There he pursued a career of almost unexampled activity for nearly half a century, engaging with indomitable energy in scientific lecturing, in work connected with medical and scientific societies, or in scientific research. In London he first resided in Bernard Street, Russell Square, whence he removed to 18 Upper Bedford Place.
Admitted a licentiate of the College of Physicians on 3 March 1809, Roget delivered in the spring of that and the following year popular lectures on animal physiology at the Russell Literary and Scientific Institution in Bloomsbury. In October 1809 he projected the Northern Dispensary, which was opened in the following June with Roget as its physician. The active duties of this office he performed gratuitously for eighteen years. In 1810 he began to lecture on the theory and practice of physic at the theatre of anatomy in Great Windmill Street, in conjunction with Dr. John Cooke, who two years afterwards resigned him his share of the undertaking. He then delivered two courses of lectures a year until 1815. In 1820 he was appointed physician to the Spanish embassy, and in 1823 physician to the Milbank penitentiary during an epidemic of dysentery. In the autumn of 1826 he commenced lecturing at the new medical school in Aldersgate Street. His introductory lecture was published. In 1827 he was commissioned by the government to inquire into the water-supply of the metropolis, and published a report next year. In 1833 he was nominated by John Fuller, the founder, the first holder of the Fullerian professorship of physiology at the Royal Institution, where, as at the London Institution, he had already lectured frequently on animal physiology. He held the Fullerian professorship for three years, and in his lectures during 1835 and 1836 confined himself to the external senses.
Meanwhile some of Roget's energy had been devoted to other fields. He always cultivated a native aptitude for mechanics. In 1814 he had contrived a sliding rule, so graduated as to be a measure of the powers of numbers, in the same manner as the scale of Gunter was a measure of their ratios. It is a logo-logarithmic rule, the slide of which is the common logarithmic scale, while the fixed line is graduated upon the logarithms of logarithms. His paper thereon, which also describes other ingenious forms of the instrument, was communicated by Dr. Wollaston to the Royal Society, and read on 17 Nov. 1814. The communication led, on 16 March 1815, to his election as a fellow of the society. On 30 Nov. 1827 he succeeded Sir John Herschel in the office of secretary to the society, retiring in 1849. He not only edited, while secretary, the ‘Proceedings’ both of the society and council, but prepared for publication the abstracts of papers. This labour he performed from 1827 to his retirement. He was father of the Royal Society Club at the time of his death.
On many other literary and scientific societies Roget's active mind left its impress. From 1811 to 1827 he acted as one of the secretaries of the Medico-Chirurgical Society; he was one of the earliest promoters of the society, and was vice-president in 1829–30. He was a founder of the Society for the Diffusion of Useful Knowledge, and wrote for its ‘Library of Useful Knowledge’ a series of treatises on ‘electricity,’ ‘galvanism,’ ‘magnetism,’ and ‘electro-magnetism,’ during 1827, 1828, and 1831. On 24 June 1831 he was elected, speciali gratia, fellow of the Royal College of Physicians, and in the following May he delivered the Gulstonian lectures on ‘The Laws of Sensation and Perception.’ He held the office of censor in the college in 1834 and 1835. Roget was a frequent attendant at the meetings of the British Association for over thirty years, and at an early meeting filled the chair of the physiological section. He wrote in 1834 one of the Bridgewater treatises on ‘Animal and Vegetable Physiology considered with reference to Natural Theology;’ it was reissued in 1839, 1840, and 1862.
In 1837 and the subsequent years he took an active part in the establishment of the university of London, of the senate of which he remained a member until his death; in
