 An advertisement for these concerts announced that "the girl" would play "the most difficult pieces by the greatest masters", while "the boy" would play a concerto on the violin and also repeat his Vienna trick of playing with the keyboard completely covered by a cloth.Finally, "he will improvise out of his head, not only on the fortepiano but also on the organ...in all the keys, even the most difficult, that he may be asked".The family proceeded by riverboat to Koblenz, Bonn and Cologne.