These two extraordinary works of late Mozart, KV 594 and KV 608, were both composed to fulfill a commission for a memorial exhibit in Vienna, to be played in a “mechanical clock organ.” The term “fantasy” or“fantasia” came to be affixed to these works later, and is more descriptive and less cumbersome than the term Mozart listed in his own catalogue, “Ein Stüke für ein Orgelwerk in ein Uhr.” They are also variouslytitled “Adagio und...