R E G E E G 347 .a work due from the Roman school, despatched from Tangiers the large canvas, Execution without Hearing under the Moorish Kings, in which the painter had played with the blood of the victim as were he a jeweller toying with rubies. The war arose, and found Regnault foremost in the devoted ranks of Buzenval, where he fell on January 19, 1871. See Corrcspondanw de H. Regnault ; Duparc, H. Regnault, sa vie ctsonauvrc; Cazalis, H. Regnault, 1843-1871 ; Bailliere, Les artistes .de mon temps ; C. Blanc, H. Regnault ; P. Mantz, Gazette du Beaux Arts, 1872. REGNAULT, HENRI VICTOR (1811-1878), was born on July 21, 1811, at Aix-la-Chapelle. His early life was a struggle with poverty. When a boy he went to Paris, and after a time succeeded in obtaining a situation in a large drapery establishment, where he remained, occupying every spare hour in study, until he was in his twentieth year. Then he entered the Ecole Polytechnique, and, after making the best use of his increased opportunities, passed in 1832 to the Ecole des Mines, where he developed an aptitude for experimental chemistry. A few years later he was appointed to a professorship of chemistry at Lyons, and devoted himself to research .amongst organic compounds. He paid little attention to theories and cared only for facts ; but, by his unequivocal proof of the substitution of chlorine for hydrogen in hydro- carbons, he greatly assisted his countrymen Laurent and Dumas in establishing the type-theory of organic com- pounds. Regnault's most important chemical work was a .series of researches, commenced in 1835, on the haloid and other derivatives of unsaturated hydrocarbons. This made him the discoverer of the vinyl group of compounds, car- bon tetrachloride (CC1 4 ), and of perchlorether (C 4 C1 10 O). He studied many of the natural alkaloids and organic acids, introduced a classification of the metals according to the facility with which they or their sulphides are oxidized by steam at high temperatures, and effected a comparison of the chemical composition of atmospheric air from all parts of the world. In 1840 Regnault was recalled to Paris by his appoint- ment to the chair of chemistry in the Ecole Polytechnique ; at the same time he was elected a member of the Academic des Sciences, in the chemical section, in room of M. Robiquet ; and in the following year he became professor of physics in the College de France, there succeeding Dulong, his old master, and in many respects his model. From this time Regnault devoted almost all his attention to practical physics; but in 1847 he published a four- volume treatise on Chemistry which was highly esteemed and has been translated into many languages. Regnault is perhaps best known by his careful redeter- mination of the specific heats of all the elements obtainable, and of many compounds solids, liquids, and gases by which he was enabled to correct the values obtained by Dulong and Petit, and to reduce the number of exceptions to their law that the specific heat of an element varies inversely as its atomic weight, and of a compound as its molecular weight. He investigated the expansibility of gases by heat, determined the coefficient for air as 0'03663, and showed that, contrary to previous opinion, no two gases had precisely the same rate of expansion. By numerous delicate experiments he proved Boyle's law that the volume of a gas is inversely as the pressure it supports to be only approximately true, and that those gases which are most readily liquefied diverge most widely from obedience to the law. Regnault studied the whole subject of thermometry critically; he introduced the use of an accurate air-ther- mometer, and compared its indications with those of a mercurial thermometer, determining the absolute dilatation of mercury by heat as a step in the process. He also paid attention to hygrometry and devised a hygrometer in which a cooled metal surface is used for the deposition of moisture. In 1854 he was appointed to succeed Ebelman as director of the celebrated porcelain manufactory at Sevres. He carried on the great research on the expansion of gases in the laboratory at Sevres, but all the results of his latest work were destroyed during the Franco-German War, in which also his son Henri (noticed above) was killed. Regnault never recovered the double blow, and, although he lived until January 19, 1878, his scientific labours ended in 1872. He wrote more than eighty papers on scientific subjects, and he made fine researches, many of them of importance, in conjunction with other workers. His greatest work, bearing on the practical treatment of steam-engines, forms vol. xxi. of the Memoires de I' Academic des Sciences. Regnault was great as a laborious worker ; in all his researches lie overcame every difficulty by his determined perseverance, his un- usual natural ingenuity in devising apparatus, and his rare power of manipulation. Although few discoveries are associated with his name, the mass of physical constants which he determined with the utmost accuracy constitutes a powerful instrument of further advance, and the thorough training which he gave his students has provided many painstaking and exact workers in the field of physics. REGNAULT, JEAN BAPTISTS, French painter, was born at Paris on 9th October 1754, and died in the same city on November 12, 1829. He began life at sea in a mer- chant vessel, but at the age of fifteen his talent attracted attention and he was sent to Italy by M. de Monval under the care of Bardin. After his return to Paris, Regnault, in 1776, obtained the Great Prize, and in 1783 he was elected Academician. His diploma picture, the Education of Achilles by Chiron, is now in the Louvre, as also the Christ taken down from the Cross, originally executed for the royal chapel at Fontainebleau, and two minor works the Origin of Painting and Pygmalion praying Venus to give Life to his Statue. Besides various small pictures and allegorical subjects, Regnault was also the author of many large historical paintings ; and his school, which reckoned amongst its chief attendants Guerin, Crepin, Lafitte, Blondel, Robert Lefevre, and Menjaud, was for a long while the rival in influence of that of David. REGNIER, MATHURIN (1573-1613), the greatest satirist of France, was born at Chartres on the 21st December 1573. His father, Jacques Regnier, was a bourgeois of good means and position ; his mother, Simonne Desportes, was the sister of the poetical Abbe" Desportes, one of the most distinguished of the disciples of Ronsard. Desportes, who was richly beneficed and in great favour at court, seems to have been regarded at once as Mathurin Regnier's natural protector and patron, and the boy himself, with a view to his following in his uncle's steps, was tonsured at nine years old. It appears that Jacques Regnier, at any rate for a time, encouraged his son to imitate his uncle in poetry also, though he afterwards changed his views. The boy was somewhat early introduced to general society of the jovial kind, for his father built a tennis court at the end of his garden which became semi- public and was much frequented. The poet's enemies said that his father had been a common gaming-house keeper, and that the court was built with the ruins of some church property ; but this seems to be mere scandal. Little is known of his youth, and it is chiefly conjecture which fixes the date of his visit to Italy in the suite of the Cardinal de Joyeuse in 1586. Others give 1583 and 1593, but the former date is certainly too early, and the latter pro- bably too late. Indeed the greatest uncertainty exists as to the dates and incidents of Regnier's short life, and his biographers hitherto have chiefly busied themselves in
