Fourth of ten programmes The violinist Jaap Schroder discusses with Christopher Hogwood the content and importance of writings by Muffat, Geminiani, Leopold Mozart and Campioni. They also talk about the differences between 18th-century violins and bows and those in use today, how ornamentation changed during the century, and the effect of these factors on the approach of a modern player to ' authentic ' performances. They illustrate their argument with music by Uccelini. Cima, Corelli, Geminiani, Bach, Boccherini and Mozart. Producer CLIVE BENNETT