In 1710 King Louis XIV put Réaumur in charge of compiling a description of the industry and natural resources of France. Réaumur devised the thermometric scale bearing his name, improved techniques for making iron and steel, and discovered the phenomenon of the regeneration of lost appendages among crayfish. The cupola furnace, still the most economical and generally used process for melting gray iron, was first built by Réaumur in 1720. In 1734 he published the first volume of his Mémoires pour servir à l'histoire des insectes (1734–42; “Memoirs Serving as a Natural History of Insects”). Five more volumes were published, and, though unfinished, his work was a milestone in entomological history.

He investigated the chemical composition of Chinese porcelain and, in 1740, devised his own formula for the so-called Réaumur porcelain. In 1752 he isolated gastric juice and investigated its role in the digestion of food.