(b Darmstadt, 1819; d Vienna, 1887).
Ger. musicologist and organist. Archivist and librarian of Vienna Society of the Friends of Music (Gesellschaft der Musikfreunde) 1866–87. Began huge biography of Haydn of which he completed only Vol. I (pubd. in 2 parts 1875, 1882). Wrote book on Mozart and Haydn in London (1867), living in London 1863–6 while engaged on research, and treatise on glass armonicas (1862) (he was grandson of first maker of them).