John, a celebrated Saxon chemist, was born in the duchy of Sleswick, in 1630. He became chemist to the elector of Saxony, the elector of Brandenburg, and Charles XI, king of Sweden, who gave him the title of counsellor in metals, and letters of nobility, with the surname of Louwenfleing. He employed 50 years in chemistry; in which, by the help of the furnace of a glasshouse which he had under his care, he made several excellent discoveries, particularly of the phosphorus of urine. He died in Sweden in 1705; and left several works, some in German, and others in Latin; among which, that entitled Observations Chymicae, and the Art of Making Glas, printed at Paris in 1752, are the most esteemed.