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seems to have aroused little interest in America, some of our naturalists, familiar as they were with the quasi-evolutionary conceptions of Leibnitz, Maupertuis, Diderot, and Buffon, must have had glimmerings of the developmental hypothesis. Jefferson, with his fossils strewn over a room of the American Philosophical Society and later over the WMte House, recognized that all beings had not been created to continue for all time. The origins of physical life occupied the specific attention of Dr, Benjamin Waterhouse of Harvard, who explained the beginnings of life in terms of "the principle of vitality" or "animation'* (which in turn was related to the First Cause). The majority of American students no doubt accepted this a priori explanation; but in its studies of the phenomenon of drowning, the Massachusetts Humane Society, established in 1795, utilized the scientific method for investigating the nature of life and death.
In chemistry the eighteenth century witnessed a virtual revolution. Tables of chemical affinities, the first isolation of a gas, the discovery of new metals and acids, and the invention of instruments for precise measurement laid the foundations for the incalculably important contributions made toward the end of the century by French chemists, particularly Lavoisier. Rejecting the widely held phlogiston theory, which assumed that but one element, phlogiston, existing in combination with metals, was capable of combustion, the French, chemists set down the metals as simple substances rather than combinations of substances and phlogiston. This capital contribution, together with the new nomenclature and the new table of chemical symbols, greatly accelerated chemical advance.
The coming of Joseph Priestley to Pennsylvania in 1794 on the one hand greatly stimulated the rising group of American chemists but on the other tended to retard the reception of the new French theories. Dr. Priestley, famous not only for his espousal of Unitarianism and of materialistic philosophy but for his discovery of oxygen and for other notable chemical contributions, endeared himself all the more to liberal Americans by virtue of the fact that he had been driven out of his own country by the wave of reactionary persecution. His experiments in his little laboratory at Northumberland, Pennsylvania, led to the discovery of carbon monoxide, the liberation of air from water, and increased knowledge about spontaneous combustion and the action of caustic alkalies on flint glass. Priestley, who proved to be a vigorous stimulus to other chem-