Homberg, Wilhelm (1652-1715), Dutch natural philosopher, was the son of an officer of the Dutch East India Company, and was born at Batavia (Java) on the 8th of January 1652. Coming to Europe with his family in 1670, he studied law at Jena and Leipzig, and in 1674 became an advocate at Magdeburg. In that town he made the acquaintance of Otto von Guericke, and under his influence determined to devote himself to natural science. He, therefore, travelled in various parts of Europe for study, and after graduating in medicine at Wittenberg, settled in Paris in 1682. From 1685 to 1690 he practised as a physician at Rome; then returning to Paris in 1691, he was elected a member of the Academy of Sciences and appointed director of its chemical laboratory. Subsequently he became teacher of physics and chemistry (1702), and private physician (1705) to the duke of Orleans. His death occurred at Paris on the 24th of September 1715. Homberg was not free from alchemistical tendencies, but he made many solid contributions to chemical and physical knowledge, recording observations on the preparation of Kunkel’s phosphorus, on the green colour produced in flames by copper, on the crystallization of common salt, on the salts of plants, on the saturation of bases by acids, on the freezing of water and its evaporation in vacuo, &c. Much of his work was published in the Recueil de l’Académie des Sciences from 1692 to 1714. The Sal Sedativum Hombergi is boracic acid, which he discovered in 1702, and “Homberg’s phosphorus” is prepared by fusing sal-ammoniac with quick lime.