WILLIAM, a celebrated chemist, born at Batavia on the 8th of January 1652, was the son of a Saxon gentleman employed in the service of the Dutch East India Company. His father intended him for the army, but having afterwards settled at Amsterdam, William prosecuted his studies at that place, whence he removed to Iena, and afterwards to Leipzig, where he studied the law. In 1674 he was received as advocate at Magdeburg, which had been indebted for a new species of celebrity to the physical experiments of Otto Guericke, and there applied himself to the study of experimental philosophy. Some time afterwards he travelled into Italy, and at Padua applied himself to the study of medicine, anatomy, and botany. He afterwards studied at Bologna; and at Rome he learned optics, painting, sculpture, and music. He then travelled into France, England, and Holland; Homberg took the degree of doctor of physic at Wirtemberg; visited Germany and the North; explored the mines of Saxony, Bohemia, Hungary, and Sweden; and returned to France, where he acquired the esteem of the learned. He was on the point of returning into Germany, when Colbert being informed of his merit, made him advantageous offers, which induced him to fix his residence at Paris. But soon afterwards he lost his protector, and also incurred the odium of returning into the bosom of the Roman Catholic church; and this double misfortune was the more sensibly felt that he had never dreamed of securing for himself any independent means of subsistence. Homberg, already well known for his phosphorus, for a pneumatic machine of his own invention more perfect than that of Guericke, for his microscopes, for his discoveries in chemistry, and for the number and variety of his curious observations, was received into the Academy of Sciences in 1691, and had committed to him the laboratory of that body, of which he was one of the principal ornaments. The Duke of Orleans, afterwards regent of the kingdom, at length made him his chemist, settled upon him a pension, gave him a superb laboratory, and in 1704 made him his first physician. Homberg, having lived for thirty-three years in the Catholic faith, died in 1715. His principal works are, 1. Manière de faire le Phosphore brûlant de Kunckel, 1692; 2. Diverses Expériences du Phosphore; 3. Réflexions sur l'expérience des Larmes de Verre qui se brisent dans le Vide; 4. Expériences sur la Germination des Plantes, 1693; 5. Essais de Chimie, 1702, 1705, 1709; 6. Observations faites par le Miroir ardent, 1702; 7. Analyse du Sulfure commun, 1703; 8. Découverte d'une liqueur qui dissout le Verre, 1703; 9. Observations sur les Araignées, 1707; 10. Mémoires touchant les Végétations artificielles, 1710; 11. Manière de copier sur le Verre coloré les Pierres gravées, 1712; 12. Observations sur une séparation de l'Or d'avec l'Argent, par la fonte, 1713; 13. Tracts on different metallic vegetations, on the generation of iron, and on the vitrification of gold. Homberg had occupied himself much with metals, and was not far from believing in the philosopher's stone.