In 1657, he was appointed professor of medicine at the
University of Mainz and physician to the archbishop-
elector. His
Metallurgia was published in 1660; and the next year appeared his
Character pro notitia linguarum universali, in which he gives 10,000 words for use as a
universal language. In 1663, he published his
Oedipum Chemicum and a book on animals, plants and minerals (
Thier- Kräuter- und Bergbuch). In 1666, he was made councillor of commerce () at
Vienna, where he had gained the powerful support of the prime minister of Emperor
Leopold I. Sent by the emperor on a mission to the
Netherlands, he wrote there in ten days his
Methodus Didactica, which was followed by the
Regeln der Christlichen Bundesgenossenschaft and the
Politischer Discurs von den eigentlichen Ursachen des Auf- und Abblühens der Städte, Länder und Republiken. In 1669, he published his
Physica subterranea; the same year, he was engaged with the
count of Hanau in a scheme to acquire
Dutch colonization of Guiana from the
Dutch West India Company. Meanwhile, he had been appointed physician to the elector of
Bavaria; but in 1670 he was again in Vienna advising on the establishment of a silk factory and propounding schemes for a great company to trade with the
Low Countries and for a canal to unite the
Rhine and
Danube. In 1678, he crossed to
England. He travelled to
Scotland where he visited the mines at the request of
Prince Rupert. He afterwards travelled for the same purpose to
Cornwall, and spent a year there. At the beginning of 1680, he presented a paper to the
Royal Society in which he attempted to deprive
Christiaan Huygens of the honour of applying the pendulum to the
measurement of time. In 1682, he returned to
London, where he wrote
Närrische Weisheit und weise Narrheit (in which, according to
Otto Mayr he made extensive references to temperature regulated furnaces), a book the
Chymischer Glücks-Hafen, Oder Grosse Chymische Concordantz Und Collection, Von funffzehen hundert Chymischen Processen and died in October of the same year. ==Legacy==