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 LAVOISIER 353 lighting the streets of Paris. To increase the sensitive ness of his eyes, he immersed himself for six weeks in a room hung with black, from which all light was excluded except that of the lamps experimented upon. His zeal was a pledge of success, and was rewarded with the gold medal, April 9, 1766. A multitude of subjects now en gaged his attention. He presented to the Academy a masterly analysis of gypsum ; travelled through France with Guettard, who was occupied in constructing the first geological map of the country, and composed a work, of which a fragment entitled Memoire snr les couches des montagnes found a place in the Academy collection for 1789 ; refuted the prevalent error as to the conversion of water into silica by repeated distillation, and studied the phenomena of thunder and aurora;, of crystallization and congelation. He became an associate of the Academy in 17G8, and in 17G9 obtained the lucrative post of farmer- general of the revenue, with a view to increase the re sources at his command for the advancement of science. It was about the year 1770 that the vast possibilities of the new field opened to the researches of chemists by the pneumatic discoveries of Black, Cavendish, and Priestley were recognized by Lavoisier, and the perception gave to his genius the definitive impulse hitherto wanting to it. He repeated and verified experiments which became, in his hands, the means of invalidating their authors conclusions, and prepared to import the clear-cut precision of his own ideas into a science as yet illogical in form and incoherent in expression. His wealth and position, as well as his enthusiasm, eminently qualified him to lead a successful reform. He lived in the midst of the most stimulating society of his time. Between him and such men as Laplace, Monge, Berthollet, and Fourcroy the constant interchange of ideas established a community of opinion in physical matters so close that the separate intellectual property of each was all but completely merged in the general stock. 1 On one day in each week Lavoisier threw open his laboratory to a select few of his friends, communi cated the results of his labours, and invited their criticism and advice. By this consultative system his work gained in solidity, and lost nothing in originality. On the 1st of November 1772 Lavoisier, eager to secure the credit of priority, deposited at the Academy a sealed packet contain ing the record of his earliest conclusions on the crucial point of metallic oxidation. The discovery by Priestley in 1774 of &quot; dephlogisticated air&quot; materially assisted the development of the innovating doctrine, which took the form of a fully fledged theory when Lavoisier in 1778 assigned to the new substance, with the name of &quot; oxygen,&quot; the important functions of the universal &quot;acidifying prin ciple.&quot; His analysis of water in 1784, and synthesis of &quot;fixed air&quot; (called by him &quot;carbonic acid,&quot; Academy Memoirs, 1781), opened the way for an extended view of the composition of organic as well as inorganic substances, and the anti-phlogistic chemistry was completed by the publication, in 1787, of the Methode de nomenclature chimique. The reform of language effected by Lavoisier in conjunction with Guyton de Morveau, Berthollet, and Fourcroy was an indispensable prelude to the reform of thought. With the current alchemistic jargon science, properly so-called, could have no fellowship. The new terminology prevailed without change for fifty years, and has been fitted, by trifling modifications, to meet the exigencies of recent progress. The acceptance of the &quot; oxygen theory &quot; was enormously facilitated by the defined and logical form given to it in Lavoisier s Traite clemen- taire de chimie (Paris, 1789). Indeed, the history of science scarcely presents a second instance of a change 1 (Euvres de Lavoisier, torn. i. p. 13. so fundamental accomplished with such ease. The parti sans of phlogiston did not, it is true, abandon the field without a struggle. In Berlin they met Lavoisier s demon strations by burning him in effigy, and in Paris Lame therie conducted, in the Journal de Physique, a fierce polemic against the party of innovation. The controversy was, however, brief, and its issue visibly certain. Before the end of the century the reformed chemistry was everywhere in a position of uncontested triumph. The enlightened activity of Lavoisier was no less con spicuous in his administrative than in his scientific capacity. A prominent member of the body of farmers-general during twenty-one years, he obtained the abolition of certain taxes equally onerous and unproductive, and earned the gratitude of the Jews of Metz by relieving them from an oppressive impost. Appointed director of the powder- works by Turgot in 1776, he not only suppressed the vexatious searches for saltpetre in the cellars of private houses, but succeeded in quadrupling the produce of the commodity. He, moreover, improved the manufacture of gunpowder so as to add one- third to its explosive force, thereby reversing the previous superiority of English over French ordnance. His philan thropic zeal was displayed in the provincial assembly of the Orleanais in 1787. In the year following he was attached to the Caisse d escompte, and presented a report of its opera tions, November 21, 1789, to the Constituent Assembly. In 1790 he sat on the commission of weights and measures. In 1791 he became commissary to the treasury, where he established a system of accounts of unexampled punctuality. Requested by the National Assembly to set forth a new scheme of taxation, he composed a treatise De la richesse territorial de la France, of which an extract, printed at the public expense, shows him to have been possessed of sound and liberal views on political economy. In short, to quote the words of Lalande, &quot;Lavoisier was to be found everywhere.&quot; But those were times when to be conspicuous was to be in peril. On the 2d of May 1794, Dupin, a member of the Convention, presented a frivolous accusation against the whole of the ex-farmers-general, whose wealth constituted in itself an inexpiable crime. Lavoisier found a hiding-place for a day or two in the deserted apartments of the Academy, but, hearing that his absence was likely to prejudice the cause of his colleagues, he voluntarily gave himself up. He thought it impossible that his life could be taken, but expected the confiscation of his property, when, as he told Lalande, he proposed to earn his bread as an apothecary. Half measures, however, were not in favour with the revolutionary tribunal. On the 6th of May, he, with twenty-seven others of the same profession, was condemned to the guillotine, and, two days later, the sentence was carried into execution. &quot; II ne leur a fallu,&quot; Lagrange remarked, &quot; qu un moment pour faire tomber cette tete, et cent annexes peut-etre ne suffiront pas pour en reproduire une semblable.&quot; It is said that a petition presented in his favour met with the brutal reply: &quot; The republic has no need of savants.&quot; He was preceded on the scaffold by M. Paulze, whose gifted daughter he had married in 1771. He left no posterity. To the gift of a transcendent intellect Lavoisier joined the charms of a noble person and winning manners. He was faithful to Lis friends, charitable to the poor, a model husband, and a patriotic public servant. His fame as the reformer of chemistry rests on no single discover}*, but is involved in the first principles of the science (see CHEMISTRY, p. 463). It was his great merit to have made the balance the ultima ratio of the laboratory. Quantitative analysis thus became for the first time possible, and a chemical reaction took in his hands the rigid form of an algebraical equation. 2 His latest studies were of a physiological character, and M. Dumas 3 found among his papers a piece showing that he had arrived at a remarkable anticipation of modern views concerning the relations 2 (Eurres, torn. i. p. 108. 3 Lemons de Chimie, 1861. XIV - 45