Du Moncel, Théodose Achille Louis

(b. Paris, France, 6 March 1821; d. Paris, 16 February 1884)

electricity, magnetism.

Du Moncel studied at the collège of Caen and at the age of eighteen published two works on perspective. After graduation he traveled through Turkey and Greece and later published an elaborate account of his travels, for which he drew the lithograph illustrations. His interest in electricity began in 1852, following the publication in Cherbourg the previous year of a work on meteorology. Some sixty-five books and papers on electricity and magnetism followed during thirty years of active writing, his works being translated into English, German, Portuguese, and Italian.

Du Moncel’s interest in electricity spanned the most fertile period of its development, from Faraday to Edison, and his publications analyzed each discovery and invention in the framework of the entire science. His early work dealt with the determination of the characteristics of electromagnets and their application to motor design, and the mutual interaction of magnets and energized conductors.

His first popular work, Exposé des applications de l’électricité, appeared in Paris in two volumes in 1853–1854 and was expanded to five volumes of 2,870 pages in 1856–1862, making it a valuable reference encyclopedia of electrical development up to that time. In it Du Moncel reviewed Charles Bourseul’s proposal for the electric transmission of speech, the earliest approach to practical telephony. Du Moncel wrote of this, “I thought it incredible,” yet it was held to have contained the germ of later Bell and Gray inventions. In the contests among telephone inventions, Du Moncel soon differentiated between those devices capable of transmitting only music and those which could transmit the more complex articulations of the human voice. He gave maximum praise to Bell. Du Moncel also described electromagnetic equipment and its widening use in telegraphy, mechanics, and medicine. His most popular work, Le téléphone, le microphone et le phonographe, was first published in Paris in 1878 and was translated into English the following year. He collaborated with Sir William Henry Preece in publishing on electric illumination in 1882 and with Frank Geraldy on electric motors in the following year.

Du Moncel’s publications also dealt with the printing telegraph, electromagnetic applications, especially electric motors and railway signals, the Ruhmkorff induction coil, lightning theory and lightning protection, the effect of the sun’s passage over telegraph lines, and the forms and operation of electric batteries, clocks, and lamps. He then turned to the Atlantic cable, mathematical analysis of electromagnets, and grounded telegraph circuits. His final work, which concerned the electric motors of P. Elias and the Pacinotti dynamo, was published in 1883.

Although Du Moncel contributed no great discovery or invention of his own, his clear, widely read books and papers spread the advances in electrical science, which was rapidly expanding. His concern was less with electrical theory than with its devices and practical applications. His assiduous experiments and interpretations of the work of his colleagues helped organize the electrical innovations from the 1850’s to the 1880’s. He accepted tasks on behalf of his nation and profession and was accorded many honors. He became a member of the Technical Committee of the Administration of Telegraphs of France in 1860 and in 1866 was named a chevalier of the Legion of Honor. He was made a member of the Institute of France, elected to the Academy of Sciences, and in 1879 became editor of Lumière électrique. He was an early member of the Society of Telegraph Engineers and Electricians of London and was awarded the Order of St. Vladimir of Russia.

BIBLIOGRAPHY

Among Du Moncel’s many books and monographs on electrical subjects are Considérations nouvelles sur lélectromagnétisme (Paris, 1853); Exposé sommaire des principes et des lois de l’électricité (Cherbourg, 1853); Exposé des applications de l’électricité, 2 vols. (Paris, 1853–1854; 2nd ed., 5 vols., 1856–1862; rev. 3rd. ed., 1872–1878); Notice sur l’appareil d’inductions électrique de Ruhmkorff(Paris, 1855; 4th ed., 1859); Notices historiques et théoriques sur le tonnerre et les éclairs (Paris, 1857); Étude du magnétisme et de l’électro-magnétisme (Paris, 1858); Revue des applications del’électricité en 1857 et 1858 (Paris, 1859); Étude des lois des courants électriques (Paris, 1860); Traité théorique et pratique de télégraphie électrique (Paris, 1864); Le téléphone, le microphone et le phonographe (Paris, 1878), Eng. trans. (New York, 1879); L’éclairage élmrique (Paris, 1880), Eng. trans. (London, 1882), Italian trans. (Turin, 1885–1887); and L’étectricité comme force motrice (Paris, 1883), Eng. trans. (London, 1883).

Bern Dinner