23ac Things especially interisting or valued because they are uncommon.(8) 19d O|rgan stop producing a bell-like sound. (8) (C?rill ) 20D rABID FLUCTUATION OF PITCH ON A SINGLE NOTE. (7) (???DA??) 21D iuN VERDI`S NABUCCO,THE KING OF JERUSALEM`S NEPHEW, IN LOVE with the King of Babylons daughter.(7) (??mea??)
22d Small metal piece suspended within a bell that causes it to sound.(7) (??a?p??) 25d Haydn mazss whose popular name includes a British naval hero.(6y) (N?l???) 31ac Abbreviation in degree titles to mean`of Oxford` (4) 32ac 6 sided prism whose sides are parallelograms. (12) (r?0?????????)