ANTOINE LAURENT LAVOISIER was born in Paris, August 26, 1743. He was educated under the eye of his father, a man of opulence, with discernment to appreciate his son's abilities, and liberality to cultivate them without regard to cost. Lavoisier early showed a decided inclination for the physical sciences; and before he was twenty years old, had made himself master of the principal branches of natural philosophy.

In 1764 the government proposed an extraordinary premium for the best and cheapest project of lighting the streets of Paris, and other large cities. To this subject, involving a knowledge of several branches of cience, Lavoisier immediately devoted his attention.

VOL. IV.

C

He produced so able a memoir, full of the most masterly, accurate, and practical views, that the gold medal was awarded to him. This production was the means of introducing him into the Academy of Sciences, of which, after a severe contest, he was admitted a member, May 13, 1768; and he proved himself through life one of its most useful and valuable associates.

At this time the whole range of chemical and physico-chemical science was in an extremely imperfect state; and the first steps to a more improved system involved the necessity of clearing away a vast mass of error which encumber the path to truth. For instance, one of the fanciful ideas, the offspring of the alchymy of the dark ages, which still continued to haunt the regions of science, was the belief of the conversion of water into earth by gradual consolidation. This subject Lavoisier treated in the true spirit of the experimental method, and clearly showed that the pretended conversion was either a deposition of earthy particles, or a sediment arising from the action of the water on the internal surface of the retort. He also laboured on the analysis of the gypsum found in the neighbourhood of Paris, and on the crystallisation of salts. He discussed the project of conveying water from L'Yvette to Paris, and the theory of congelation; and to these researches added extensive observations on the phenomena of thunder and the Aurora Borealis.

He next directed his attention more especially to mineralogy; and made excursions, in conjunction with Guettard, into all parts of France, endeavouring to form from different districts a complete collection of their characteristic mineral productions. He made advances towards a systematic classification of facts connected with the localities of fossils, which afterwards served as the basis of his work on the revolu

tions of the globe and the formation of successive strata, of which two admirable abstracts were inserted in the Memoirs of the Academy of Sciences, for 1772 and 1787.

Thus during the earlier part of his life, Lavoisier does not seem to have devoted himself in particular to any one branch of science. But about the year 1770 the announcement of the existence of more than one species of gaseous matter, arising out of the successive researches of Black, Scheele, Priestley, and Cavendish, had the effect of fixing his attention to the subject of pneumatic chemistry. The invaluable discoveries just alluded to had opened a new world to the inquirer into nature; and the labours of those distinguished experimentalists had conspired to commence a fresh era in science. Lavoisier was one of the first to appreciate at once the importance of the results they had arrived at, and the immense field of further research to which those results had opened the way. He perceived by a sort of instinct the glorious career which lay before him; and the influence which this new science thus, as it were, created, must have over every sort of physical research. Priestley possessed precisely those qualifications which are most available for striking out new and brilliant discoveries of facts; a boundless fertility of invention; a power of rapidly seizing remote analogies; and an equal readiness in framing and in abandoning hypotheses, which have no value, but as guides to experiment. Lavoisier, less eminent in these respects, possessed in a more peculiar degree the mental characteristics which enable their owner to advance to grand generalisations and philosophical theories upon the sure basis of facts. He possessed, in its fullest sense, the true spirit of inductive caution, and even geometrical rigour; and his observations, eminently precise and luminous, always pointed to more general views.

In 1774 he published his Opuscules Chimiques,' in which, after a full and truly philosophical examination of the labours of preceding experimenters in the discovery of the gases and their characteristic properties, he proceeds to describe his own beautiful and fundamentally important researches, from which resulted the True Theory of Combustion,' which may be termed the very sun and centre of the whole modern system of chemistry.

To the vague dreams of the alchymist had succeeded the remarkable theory of Hooke, who maintained that a certain ingredient of the atmospheric air (which also enters as an ingredient into several other bodies, especially nitre) was the solvent which absorbed a portion of the combustible. This process was continued in proportion as more of the solvent was supplied. The solution took place with such rapidity, as to occasion those motions or pulsations in which Hooke believed heat and light to consist.

This near approach to the truth was thrown into discredit by the more brilliant and imposing theory of Stahl, who captivated the imaginations of chemists by his doctrine of phlogiston, the principle or element of fire, a sort of metaphysical something, which conferred the property of being combustible. Stahl taught that the process of combustion deprived bodies of their phlogiston, which, in the act of separation, exhibited its latent energies in the evolution of light and heat.

This wild chimera long maintained its ground, and received successive modifications in the hands of several distinguished chemists, the most important of which was that of Kirwan; but these all retained the fundamental error that something was abstracted from the burning body. Yet Rey, so early as 1630, and Bayer afterwards, had both shown that metals by calcination increase in weight, or have something

added to them. Lavoisier turned his attention to the defects of the existing theory about 1770; and the last-named experiments probably directed him more specifically to the essential point of the inquiry. He pursued his researches with unwearied industry; and by a long series of experiments of the most laborious and precise nature, he succeeded in determining that, in all cases of combustion, that substance which is the real combustible invariably receives an addition, or enters into a new combination; and the matter with which it combines is in all cases that same substance which had now been shown by Priestley to be one of the constituents of the atmosphere, and which was then known by the name of vital air.

It was however long before Lavoisier gained a single convert. At length M. Berthollet, at a meeting of the Academy in 1785, publicly renounced the old opinions and declared himself a convert. Fourcroy followed his example. In 1787, Morveau, during a visit to Paris, became convinced, and declared the conclusions of Lavoisier irresistible. The younger chemists speedily embraced the new views; and their establishment was thus complete. There only remained some lurking prejudices in England, where the Essay of Kirwan retained its credit. Lavoisier and his coadjutors translated this essay into French, accompanying each section by a refutation. So completely was this done, that the author himself was convinced; and, with that candour which distinguishes superior minds, gave up his views as untenable, and declared himself a convert.

These discoveries introduced Lavoisier to the notice of the most eminent persons in the State; and in 1776 Turgot engaged him to superintend the manufacture of gunpowder for the Government. He introduced many valuable improvements in the process, and many judicious reforms into the establishment.