LEBLANC, Nicolas, French chemist: b. Issoudun, department of Indre, 1742; d. Saint Denis, 16 Jan. 1806. He studied medicine, was appointed surgeon to the Duke of Orleans and, after the Revolution, administrator of the de partment of the Seine. His name is associated with the process of converting common salt into carbonate of soda, a matter to which he turned his attention in 1786, after the Academy had offered a prize of 2,500 livres for the dis covery. His first endeavors did not yield a decisive result, but led to an accidental dis covery by Dize, an assistant of Jean Darcet (q.v.) at the College of France, through which success was attained. Prior to this time soda was obtained from natural deposits and the ashes of marine plants, the supply of which had become insufficient. With the Duke of Orleans and another, Leblanc and Dize formed a part nership and began to make soda. The Revolu tion wrecked their enterprise. Despite his pat ent for 15 years, secured in 1791, Leblanc was compelled by the committee of public safety to disclose the secret of the process, and the manufacture became open to all. After years
of poverty and fruitless efforts for redress, he committed suicide. The discovery of the essen tial features of the process was assigned to him in 1855 by a commission of the Academy, although the claim of Dize was strongly ad vocated. As to the value of the process itself there is no doubt. It has made soda cheap, thereby facilitating the manufacture of soap, the cleansing and bleaching of cloth, etc.; has promoted the manufacture of sulphuric acid, and thereby the utilization of metallic sul phides; and has originated the manufacture of chlorine and of bleaching-powder. The Leblanc soda-process is still in extensive use, but is now dependent more on its by-products than on its output of soda One-half of the world's soda is now made by the ammonia-soda or Solvay process. See SODA.