Johann Jakob Biedermann (Winterthur, 1763 - Zurich, 1830) THE ROSENLAUI GLACIER pen, brown ink and bodycolour, 460x750 mm on the recto, lower left, pen and brown ink: "J. J. Biedermann". THE ROSENLAUI GLACIER pen, brown ink and gouache, 460x750 mm on the recto, lower left, pen and brown ink: "J. J. Biedermann"