So-na, Yueh-ch 'in and La-pa - The Chinese So-na is a copper wind instrument having seven holes above and two thumb-holes below, thus giving nine notes as in the Scotch bagpipe which it somewhat resembles in tone. The Yueh-ch in or 'Moon Guitar', so called from the shape of its sound box, has four silk strings; these are usually struck with the fingernails. The long Chinese trumpet known as the La-Pa has a sliding tube like the trombone, and although it is primarily a military instrument, knife-grinders have a privilege which enables them to use it in the streets to announce their arrival!