At these meetings general discourse and philosophic discussion were agreeably intermingled; the opinions of the most eminent philosophers were freely canvassed; the most striking and novel passages in the publications of foreign countries were made known, recited, and animadverted upon; and the progress of experiment was assisted by candid comments and comparison with theory. In these assemblies might be found, mingling in instructive and delightful conversation, all those whose names made the last century memorable in the annals of science. Priestley, Fontana, Landriani, Watt, Bolton, and Ingenhouz, were associated with Laplace, Lagrange, Borda, Cousin, Monge, Morveau, and Berthollet. There was also an incalculable advantage in bringing into communication and intimacy men engaged in distinct branches of science: the intercourse of the mathematician with the geologist, of the astronomer with the chemist, of the computer with the experimenter, and of the artist with the theorist, could not fail to be of mutual advantage. In no instance were the beneficial effects of such intercourse more strikingly displayed than in the chemical sciences; which, from this sort of comparison of ideas and methods, began now to assume a character of exactness from an infusion of the spirit of geometry; and a department hitherto abandoned to the wildest speculations, and encumbered with the most vague and undefined phraseology (derived from the jargon of the alchemists), began to assume something like arrangement and method in its ideas, and precision and order in its nomenclature. This influence was strongly marked in the physical memoirs produced in France from this period downwards. The precision and severity of style, and the philosophical method of the mathematicians, was insensibly transfused into the papers of the physical and chemical philosophers. Lavoisier individually profited greatly by the sources of improvement and information thus opened. Whenever any new result presented itself to him, which, perhaps, from contradicting all received theories, seemed paradoxical, or at variance with all principles hitherto recognised, it was fully laid before these select assemblies of philosophers; the experiment was exhibited in their presence, and they were invited with the utmost candour to offer their criticisms and objections. In perfect reliance on the mutual spirit of candour, they were not backward in urging whatever difficulties occurred to them, and the truth thus elicited acquired a firmness and stability in its public reception proportioned to the severity of the test it had undergone. Lavoisier seldom announced any discovery until it had passed this ordeal.