War and Post-War

Haas continued to teach during the first months of the war but was eventually drafted to the Army. His strong dislike of military affairs was a matter of record and the authorities charged him with the maintenance of the horse stables for the cavalry. His commanding officer had more appreciation for his academic titles and Haas enjoyed relatively peaceful but boring war years. He used the time to write a first textbook of modern physics. With the collapse of Germany and inner revolutionary struggles, Haas decided to return to Vienna. But, being from Brno, he saw himself identified as a Czech citizen.