He published his geographical, geological, economic, and ethnological findings in three volumes with an atlas, which, however, did not cover the entire field or complete the author's plan. This work appeared at Berlin in 1877-85 under the title of "China: Ergebnisse eigener Reisen und darauf gegründeter Studien". In this standard work, the author deals not only with geology but with every subject necessary to a general geographical treatise. Notably he paid close attention to the economic resources of the country he traversed. He also wrote a valuable series of letters to the Shanghai Chamber of Commerce, and first drew attention to the importance of the coalfields of Shantung, and of Kiaochow as a port.