Carl Kassner

[2] After school, he enrolled in the Philosophical Faculty of the Friedrich Wilhelm University in Berlin, where he studied theology and philosophy until the seventh semester.

[2] He became acquainted with Otto Lilienthal through the German Association for the Promotion of Aviation, where he gave a lecture on cloud photography and which he joined in January 1892.

[6] In the 1890s, Kassner took part in several scientific balloon flights organized by the Association for the Promotion of Airship Travel[5] and took "sensational cloud photos".

From 1901, in addition to his work at the Prussian Meteorological Institute, Kassner was a private lecturer at the Royal Technical University of Charlottenburg.

[9] After the outbreak of the First World War, Kassner was one of the signatories of the Declaration of the University Teachers of the German Empire of 16 October 1914.

[10] Between the turn of the century and the First World War, Kassner had travelled throughout almost all of Europe, Asia Minor and Algeria.

Even after the war, Kassner was an important advocate for the Balkan state as deputy director and later honorary member of the German-Bulgarian Society, giving public lectures about the country and its people.