1853—Leipzig, Germany

Ferdinand Gleich, a German composer and author, writes his Handbuch der modernen Instrumentirung für Orchester und Militairmusikcorps. In his section on alto trombone, he mentions that music for alto trombone is notated in alto clef, that the alto trombone is an e-flat instrument (although it is non-transposing), and that it has the following chromatic range (public domain image; Gleich 48-49):