The influence Petermann tried to wield, even as a young man, can best be illustrated by his interference, together with Bunsen and Ritter, on behalf of Heinrich Barth, who wished to take part in the Richardson expedition. He later also persuaded the English government to send Eduard Vogel after them for scientific research and astronomical observations. Petermann published the results under the title "Account of the expedition to Central-Africa". When first Barth and later Vogel failed to return at the expected time Germany frantically tried to discover their fate, much as Britain had with Franklin in the Arctic area. This led to many new German expeditions to Africa (by Theodor von Heuglin, Hermann Steudner, Theodor Kinzelbach, Karl Moritz von Beurmann, Gerhard Rohlfs, Karl Mauch and others), most financed by gifts due largely to Petermann's agitating actions and publications. Many found their death in Africa as shown in the map with the subtitle "Four martyrs of German science in Inner-Africa" shows, i.c. Overweg, Vogel, Beurmann and Steudner.