Lang earned his doctorate from the
University of Giessen in 1859 with a thesis titled "Physikalische Verhältnisse kristallisierter Körper". From 1865 to 1909, Lang served as director of the
Physikalisches Kabinett in
Vienna. His book on introductory
theoretical physics,
Einleitung in die theoretische physik, was published in eight editions from 1867 to 1891. With
crystallographer Wilhelm Josef Grailich, he was co-author of
Untersuchungen über die Physikalischen Verhältnisse Krystallisirter Körper ("Investigations into the physical conditions of crystallized bodies"). The mineral
langite was named in his honor by
Nevil Story Maskelyne. ==References==