To illustrate the strength of its music collection to the Board of Visitors of the Music Department, Widener Library is opening an exhibition today of exceptionally rare and interesting manuscripts, dating from the Renaissance to the present. Forming the basis of the six-case display are a group of autographed holograph manuscripts of Beethoven, Chopin, Rubinstein, Betini, and Haydn.

By examining the exhibited printings, it is possible to trace the development of music printing. In the first fifty years after printing was invented, from 1450 to 1500, no effective system was discovered for writing notes; but, in 1503, Ottavino dei Petrucci contrived movable type of sufficient accuracy to cope with the demands of the elaborate new "florid song," or counterpoint. There is shown a unique selection of Petrucci's editions, which required separate impressions for letters, staffs, and notes.

The Library's collection is chiefly noted for a very rare group of the works of John Playford, an English music publisher of the late seventeenth century. To the casual viewer, Playford's "An Introduction to the Skill of Music" may appear very striking, since it provides first-hand information of the ideas which people held about music in 1654.

Lovers of the madrigal will take particular delight in a number of the first editions of the English composers William Byrd, Thomas Morley, Thomas Watson, and John Amner. In addition to Byrd's first editions are shown a set of four part-song manuscripts of his madrigals.

An especially noteworthy unit of the exhibition is a copy of the first edition of Gaforius's "Practical Musicae," which was the most important book on music theory in the Renaissance.