161 - BUFFON (Georges Louis Leclerc, Count of), 1707–1788.

BUFFON (Georges Louis Leclerc, Count of), 1707–1788. Autograph letter signed “Buffon,” Paris, April 18, 1739, 2½ pages in-4 format in brown ink, trace of a red wax seal (small cut or corner tear with minor loss of text), addressed to Étienne-François Dutour, tax collector in Riom, but above all a physicist and naturalist. A fine scientific letter by the young Buffon, a true declaration of faith in the experimental method, written just three months before his appointment as director of the Jardin du Roi. To his correspondent, who had shared his reflections on optical phenomena, Buffon gently chides him for “rushing a bit too quickly to a system”: before constructing a theory, one must “have clearly observed and thoroughly gathered all the facts,” for “systems teach nothing and serve, at best, only to exercise the mind.” He therefore urges him to experiment rather than “waste [his] time systematizing”: here, ten years before the first volumes of *Natural History*, we already find one of the key tenets of Buffon’s scientific method. The discussion focuses in particular on the colored rings produced by thin sections and the phenomena of the decomposition of light. Familiar with Newton’s work—of which he would publish a translation of the “Method of Fluxions” the very next year— Buffon nevertheless does not hesitate to admit that he is “no more satisfied with Newton’s explanation” than with the one proposed by his correspondent: a significant rejection of any appeal to authority on a question he still considers too new and which, in his view, requires “a very large number of experiments.” He then suggests several experiments to be conducted using convex lenses or flat mirrors in order to study the formation of colored rings. Finally, the letter contains an early and interesting mention of his fellow Montbard native Louis Daubenton, whom people “still […] hold out hope for.” Six years later, Buffon—who had since become intendant of the King’s Garden—would admit Daubenton to the Cabinet of Natural History; Daubenton would go on to become his principal collaborator on the first fifteen volumes of *Natural History*. A fine letter in which the experimentalist, the opponent of premature theories, and the future architect of *Natural History* are all already evident. Accompanied by its original cultural property export certificate from the Ministry of Culture (noting its provenance from the Charavay catalog of February 1993, no. 43558).