Dionysius Lardner

• Name — Dionysius Lardner • Born — 3 April 1793 • Birthplace — Dublin, Ireland • Died — 29 April 1859 • Place of death — Naples, Kingdom of the Two Sicilies • Education — Trinity College, Dublin • Known for — Cabinet Cyclopedia

Lardner was born in Dublin on 3 April 1793 as the son of William Lardner and his wife; William was a solicitor in Dublin who wished his son to follow the same calling. After some years of uncongenial desk work, Lardner entered Trinity College, Dublin, in 1812. He obtained a B.A. in 1817 and an M.A. in 1819, winning many prizes. Lardner married Cecilia Flood on 19 December 1815, but they separated in 1820 and were divorced in 1835. About the time of the separation, he began a relationship with a married woman, Anne Maria Darley Boursiquot, the wife of a Dublin wine merchant of Huguenot ancestry. It is believed that he fathered her son, Dion Boucicault, who became an actor and dramatist. Lardner provided him with financial support until 1840. While in Dublin, Lardner began to write and lecture on scientific and mathematical matters, and to contribute articles for publication by the Irish Academy.

In 1828, Lardner was elected professor of natural philosophy and astronomy at University College London, a position he held until he resigned his professorship in 1831. Lardner showed himself to be a successful populariser of science, giving talks on contemporary topics such as Babbage's Difference Engine (1834). He was the author of numerous mathematical and physical treatises on such subjects as algebraic geometry (1823), differential and integral calculus (1825), and the steam engine (1828). He also wrote handbooks on various departments of natural philosophy (1854–1856). However, it is as the editor of The Cabinet Cyclopædia (1830–1844) that he is best remembered. The Cabinet Cyclopædia eventually comprised 133 volumes, and many of the ablest savants of the day contributed to it. Sir Walter Scott contributed a history of Scotland and Thomas Moore contributed a history of Ireland. Connop Thirlwall provided a history of Ancient Greece and Robert Southey provided a section on naval history. Many eminent scientists contributed as well. Lardner himself was the author of the treatises on arithmetic, geometry, heat, hydrostatics and pneumatics, mechanics (in conjunction with Henry Kater) and electricity (in conjunction with Charles Vincent Walker). The Cabinet Library (9 vols., 1830–1832), the Edinburgh Cabinet Library (38 vols., 1830–1844) and the Museum of Science and Art (12 vols., 1854–1856) were his other chief undertakings. A few original papers appear in the Royal Irish Academy's Transactions (1824), in the Royal Society's Proceedings (1831–1836) and in the Astronomical Society's Monthly Notices (1852–1853); and two Reports to the British Association on railway constants (1838, 1841) are from his pen.

In 1840, Lardner's career received a major setback as a result of his romantic involvement with Mary Spicer Heaviside, the wife of Captain Richard Heaviside of the Dragoon Guards. He had previously been married to Cecilia Flood from 1815 to their separation in 1820. Lardner ran off to Paris with Mary, pursued by her husband. When he caught up with them, Richard subjected Lardner to a flogging but was unable to persuade Mary to return with him. Later that year, he successfully sued Lardner for criminal conversation (also known as adultery) and received a judgment of £8,000. The Heavisides were divorced in 1845, and in 1846 Lardner was able to marry Mary. The scandal caused by his affair with a married woman effectively ended his career in England, so Lardner and his wife remained in Paris until shortly before his death in 1859. He was able to maintain his career by lecturing in the United States between 1841 and 1844, which proved financially rewarding, realising £40,000. Lardner died in Naples, Italy, and is buried in the English Cemetery there.

Lardner became involved in a number of ill-advised public disagreements with Isambard Kingdom Brunel regarding technical matters, in which he came off the worse. During 1833 Parliamentary hearings discussing the proposal of the Great Western Railway, Lardner criticised Brunel's design of the Box Tunnel. The tunnel had a 1-in-100 gradient from the east end to the west end. Lardner asserted that if a train's brakes were to fail in the tunnel, it would accelerate to over 120 mph, at which speed the train would break up and kill the passengers. Brunel pointed out that Lardner's calculations had made a basic error in totally disregarding air resistance and friction. In 1836, when Brunel was proposing to build SS Great Western for the 3500 mi transatlantic passage to New York, Lardner stated at a meeting of the British Association for the Advancement of Science that: As the project of making the voyage directly from New York to Liverpool, it was perfectly chimerical, and they might as well talk of making the voyage from New York to the moon... 2080 mi is the longest run that a steamer could encounter – at the end of that distance she would require a relay of coals. Again, Brunel showed that Lardner's calculations were too simplistic. The principle that Brunel understood and Lardner did not was that the carrying capacity of a ship increases as the cube of its dimensions, while the water resistance only increases as the square of its dimensions. This meant that large ships were more fuel-efficient and could carry sufficient coal for the long voyage across the Atlantic. Brunel was proved right when the Great Western steamed into New York Harbour with 200 LT of coal to spare. In 1838, while Brunel was building the broad-gauge Great Western Railway, Lardner carried out some experiments with the company's flagship locomotive, North Star. He asserted that, while the engine was capable of hauling 82 LT at 33 mph, it was only capable of hauling 16 LT at 41 mph. He also recorded excessive fuel consumption at higher speeds. Lardner attributed this to the greater wind resistance of broad-gauge engines. Brunel and his assistant Daniel Gooch carried out their own experiments on the same locomotive and found that the only problem was that the blastpipe was too small. This was easily rectified, and the North Star's performance immediately improved. At the next meeting of the company's directors, Brunel triumphantly dismissed Lardner's claims.