He subsequently studied medicine and took his degree at Padua in 1618, but again filled a chair of mathematics at Rostock in 1624. He was prevented by the thirty years' war from accepting a professorship of medicine at Helm-stedt, and lived in retirement at Brunswick and Rostock till 1629, when he became rector of the Hamburg Johanneum. Leibnitz ranks him, on account of his perspicacity in opposing the scholastic school of philosophy, next to Copernicus and Galileo, and not far below Descartes. His works include Geometria Empirica (Hamburg, 1688). Johann Vaget edited his MS. Joachim Jungius Isagoge Phytoscopica, etc. (Hamburg, 1678), in which he anticipated Linnaeus in suggesting technical terms relating to botany and in other respects. - See Guhrauer, Joachim Jung und sein Zeitalter (Stuttgart, 1851), and Ave-Lallemont, Des Dr. J. Jungius aus Lubeck Briefweschsel mit seinen Schulern und Freunden (Lubeck, 1863).