Francois Napoleon Marie Moigno (De Yillebeau), a Erench scientific author, born at Guemene, Morbihan, April 20, 1804. He studied successively at Pontivy and Ste. Anne d'Auray, entered the society of Jesus in 1822, and devoted himself especially to the study of physical and mathematical science, He discovered in 1828 a new formula for the equation of tangential planes, and in 1830 followed the exiled Jesuits to Brieg in Valais. There, while completing his course of theology and pursuing Greek and Latin literature, he learned English, German, Dutch, Italian, Spanish, Portuguese, Hebrew, and Arabic. In 1836 he was appointed professor of mathematics in the Jesuit school in Paris, where he acquired reputation as a preacher, helped to found several charitable institutions, and contributed to the press papers on science and theology. In 1840 he published the first two volumes of his work on differential and integral calculus, based on the method of Cauchy. He became secretly involved in ruinous engineering speculations, and his superiors, after paying a large sum of money to extricate him from his difficulties, appointed him professor of Biblical literature in the seminary of Laval. He resisted this appointment, and left the order in 1844 In 1845 he became scientific editor of the Epoqiie, and made a tour of observation through England, Belgium, Holland, and Germany, the result of which appeared in a series of remarkable letters to that journal.

He became scientific editor of the Presse in 1850, and soon after of the Pays. In 1852 he founded the weekly scientific review Cosmos of which he remained chief editor till 1863, when he established a separate scientific weekly, Lcs Mondes. He was chaplain of the lycee Louis-le-Grand from 1848 to 1851; was attached to St. Germain-des-Pres in 1863; and in 1873 was appointed a canon of St. Denis. His works embrace Lecons de calcul differentiel et integral (4 vols., 1840-61); Repertoire d'op-tique moderne (4 vols., 1847-'50); Traite de la telegraphie electrique (1849); Le stereoscope (1852); Le saccharimetre (1853); Impossilrilite du nomhre infini et de ses consequences, demonstration du dogme de la creation et de la re-cente apparition des mondes (1863); Resumes oraux du progres seientifiqve et industriel (1865-'9); Goursde sciencevulgarisee (1865- 6); Lecons de mecanique analytique (1867); Les eclairages wodernes (1868)'; L'Art des projections (1872); and translations of three essays severally from Grove's, Hoffmann's, and Tyn-dall's scientific writings.