ERNEST

LAVISSE (1842– )  , French historian, was born at Nouvion-en-Thierache, Aisne, on the 17th of December 1842 . In 1865 he obtained a fellowship in history, and in 1875 became a doctor of letters; he was appointed maitre de conference (1876) at the ecole normale superieure, succeeding Fustel de Coulanges, and then professor of modern history at the Sorbonne (1888), in the place of Henri Wallon . He was an eloquent professor and very fond of young people, and played an important part in the revival of higher studies in France after 1871 . His know-ledge of pedagogy was displayed in his public lectures and his addresses, in his private lessons, where he taught a small number of pupils the. historical method, and in his books, where he wrote ad probandum at least as much as ad narrandum: class-books, collections of articles, intermingled with personal reminiscences (Questions d'enseignement national, 1885; Etudes et etudiants, 1890; A propos de nos ecoles, 1895), rough historical sketches (Vue generale de t' histoire politique de l' Europe, 1890), &c . Even his works of learning, written without a trace of pedantry, are remarkable for their lucidity and vividness . After the Franco-Prussian War Lavisse studied the development of Prussia and wrote Etude sur l'une des origines de la monarchic prussienne, ou la Marche de Brandebourg sous la dynastic ascanienne, which was his thesis for his doctor's degree in 1875, and Etudes sur l'histoire de la Prusse (1879) . In connexion with his study of the Holy Roman Empire, and the cause of its decline, he wrote a number of articles which were published in the Revue des Deux Mondes; and he wrote Trois empereurs d'Allemagne (1888), La Jeunesse du grand Frederic (1891) and Frederic II. avant son avenement (1893) when studying the modern German empire and the grounds for its strength . With his friend Alfred Rambaud he conceived the plan of L'Histoire generale du IV' siecle jusqu'd nos jours, to which, however, he contributed nothing . He edited the Histoire de France depuis les origines jusqu'd la Revolution (1901– ), in which he care-fully revised the work of his numerous assistants, reserving the greatest part of the reign of Louis XIV. for himself . This spicuous member, was regarded by the convention with no friendly eyes as being tainted with " incivism," and in the spring of 1792 A . F . Fourcroy endeavoured to persuade it to purge itself of suspected members .

The

attempt was unsuccessful, but in August of the same year Lavoisier had to leave his house and laboratory at the Arsenal, and in November the Academy was forbidden until further orders to fill up the vacancies in its numbers . Next year, on the 1st of August, the convention passed a decree for the uniformity of weights and measures, and requested the Academy to take measures for carrying it out, but a week later Fourcroy persuaded the same convention to suppress the Academy together with other literary societies patentees et dotees by the nation . In November it ordered the arrest of the ex-farmers-general, and on the advice of the committee of public instruction, of which Guyton de Morveau and Fourcroy were members, the names of Lavoisier and others were struck off from the commission of weights and measures . The fate of the ex-farmers-general was sealed on the and of May 1794, when, on the proposal of Antoine Dupin, one of their former officials, the convention sent them for trial by the Revolutionary tribunal . Within a week Lavoisier and 27 others were condemned to death . A petition in his favour addressed to Coffinhal, the president of the tribunal, is said to have been met with the reply La Republique n'a pas besoin de savants, and on the 8th of the month Lavoisier and his companions were guillotined at the Place de la Revolution . He died fourth, and was preceded by his colleague Jacques Paulze, whose daughter he had married in 1771 . " Il ne leur a fallu," Lagrange remarked, " qu'un moment pour faire tomber cette tete, et cent annees peat-etre ne suffiront pas pour en reproduire une semblable," Lavoisier's name is indissolubly associated with the overthrow of the phlogistic doctrine that had dominated the development of chemistry for over a century, and with the establishment of the foundations upon which the modern science reposes . "He discovered," says Justus von Liebig (Letters on Chemistry, No . 3), " no new body, no new property, no natural phenomenon previously unknown; but all the facts established by him were the necessary consequences of the labours of those who preceded him . His merit, his immortal glory, consists in this—that he infused into the body of the science a new spirit; but all the members of that body were already in existence, and rightly joined together." Realizing that the total weight of all the products of a chemical reaction must be exactly equal to the total weight of the reacting substances, he made the balance the ultima ratio of the laboratory, and he was able to draw correct inferences from his weighings because, unlike many of the phlogistonists, he looked upon heat as imponderable . It was by weighing that in 1770 he proved that water is not converted into earth by distillation, for he showed that the total weight of a sealed glass vessel and the water it contained remained constant, however long the water was boiled, but that the glass vessel lost weight to an extent equal to the weight of earth produced, his inference being that the earth came from the glass, not from the water .

On the 1st of November 1772 he deposited with the Academy a sealed

note which stated that sulphur and phosphorus when burnt increased in weight because they absorbed " air," while the metallic lead formed from litharge by reduction with charcoal weighed less than the original litharge because it had lost " air." The exact nature of the airs concerned in the processes he did not explain until after the preparation of " dephlogisticated air " (oxygen) by Priestley in 1774 . Then, perceiving that in combustion and the calcination of metals only a portion of a given volume of common air was used up, he concluded that Priestley's new air, air eminemment pair, was what was absorbed by burning phosphorus, &c., "non-vital air," azote, or nitrogen remaining behind . The gas given off in the reduction of metallic calces by charcoal he at first supposed to be merely that contained in the calx, but he soon came to under-stand that it was a product formed by the union of the charcoal with the " dephlogisticated air " in the calx . In a memoir presented to the Academy in 1777, but not published till 1782, section occupies the whole of volume vii . It is a remarkable piece of work, and the sketch of absolute government in France during this period has never before been traced with an equal amount of insight and brilliance . Lavisse was admitted to the Academic Frangaise on the death of Admiral Jurien de la Graviere in 1892, and after the death of James Darmesteter became editor of the Revue de Paris . He is, however, chiefly a master of pedagogy . When the ecole normale was joined to the university of Paris, Lavisse was appointed director of the new organization, which he had helped more than any one to bring about .