the family following the death of Lady Romilly. In 1823 Roget and Peter Mere Latham were brought in to investigate disease at Millbank Penitentiary. In 1828 Roget, with William Thomas Brande and Thomas Telford, submitted a report on London's water supply. In 1834 he became the first Fullerian Professor of Physiology at the Royal Institution. One of those who helped found the University of London in 1837, he was an examiner in physiology there. He gave up medical practice in 1840. Later life In later life Roget became deaf and was cared for by his daughter, Kate. He died while on holiday in West Malvern, Worcestershire, aged 90, and is buried there in the churchyard of St James' Church. There is a memorial to him at his local parish church of St Mary on Paddington Green Church. Thesaurus Roget retired from professional life in 1840, and by 1846 was working on the book that perpetuates his memory today. It has been claimed that Roget struggled with depression for most of his life, and that the thesaurus arose partly from an effort to battle it. A biographer stated that his obsession with list-making as a coping mechanism was well established by the time Roget was eight years old. In 1805, he began to maintain a notebook classification scheme for words, organized by meaning. During this period he also moved to Manchester, where he became the first secretary of the Portico Library. The catalogue of words was first printed in 1852, titled Thesaurus of English Words and Phrases Classified and Arranged so as to Facilitate the Expression of Ideas and Assist in Literary Composition. During Roget's lifetime, the work had twenty-eight printings. After his death, it was revised and expanded by his son, John Lewis Roget (1828–1908), and later by John's son, the engineer Samuel Romilly Roget (1875–1953). Roget's private library was put up for auction in 1870 at Sotheby's and its catalogue has been analyzed. Other interests Roget was elected a Fellow of the Royal Society in 1815, in recognition of a paper on a slide rule with a loglog scale. He was a secretary of the Society from 1827 to 1848. On 9 December 1824, Roget presented a paper on a peculiar optical illusion to the Philosophical Transactions, which was published in 1825, as Explanation of an optical deception in the appearance of the spokes of a wheel when seen