Rene Antoine Ferchault De Reaumur, a French natural philosopher, born in La Rochelle, Feb. 28, 1683, died Oct. 18, 1757. He studied law at Bourges, but went to Paris in 1703, gained distinction by his philosophical researches, and in 1708 was admitted to the academy of sciences. In his L'Art de convertir le fer forgé en acier, et l'art d'adoucir le fer fondu (1722), he first made known in France the process of manufacturing steel. For this he received a pension of 12,000 livres, which he applied to the encouragement of the industrial arts. He invented a process for tinning iron, and made experiments in the manufacture of porcelain; an opaque white glass which he made is known as "Reaumur's porcelain." He also discovered the means of preserving eggs, and made experiments in artificial incubation. In 1731 he invented the thermometer which is called after him, and is still largely used in Germany and other parts of the European continent, taking as the extremes the freezing and boiling points of water, and dividing the interval into 80 degrees.
He investigated many curious topics in natural history, especially the mode of formation and growth of the scales of fishes, the development of the shells of testaceous animals, the reproduction of the claws of lobsters and crabs, and the mode of motion of star fishes and various mollusks and zoophytes. He discovered a species of mollusk that furnishes a purple dye nearly equal to that used by the ancients. His most thorough investigations were in the department of entomology, to which he devoted several years. He published Mémoires pour servir à l'histoire natu-relle des insectes (6 vols. 4to, 1734-'42), and a variety of papers in the transactions of the academy of sciences.