Because of all these contacts the students were confronted with many opinions and views on the state of science and the world that would not normally have been part of their curriculum. Besides, we may take Poggendorff seriously when he sees Petermann as 'private secretary and librarian of H.K.W. Berghaus' in the years 1839–45, so we can assume that Petermann was at least quite up to date on many affairs to do with geography and cartography, for Berghaus had large collections of maps, books and notes to draw on.