 His "Tour of a German artist in England" (1833 in German; 1836 translated into English by Lady Eastlake) remains a significant source for art historians, as do his catalogues of old master prints, whose numbering is still followed by some collections.In the year 1839 he became Inspektor (curator) of the Städelsches Kunstinstitut in Frankfurt.There he acquired important works in the prints and drawing area, mounted exhibitions, and taught.