Some curiosities of string sound assembled in today's programme of record requests. CHRISTOPHER hogwood explains and illustrates the baryton, the scordatura violin (Biber's Mystery Sonata No 11), the arpeggione (Schubert), plus a Bach Fugue for solo violin played by HEIFETZ, two Paganini Caprices played by PERLman, a gypsy Czardas and some early Viennese dance music.