The MS. exhibited this evening by the Provost and Fellows of Eton College belongs to a class of which very few now exist in this country. It consists of a collection of motets and magnificats for several voices, the music of each part being so written upon opposite pages that when the book is open the different parts can be sung by all the singers at the same time. This was the earliest method of writing part-music. It is found in the great collection of church music formerly preserved at Trent, a collection which contains numerous specimens of the English composers of the fifteenth century; it is also found in the Modena MS. (the chief source of our knowledge of John Dunstable) at Bologna, and, indeed, in all early MSS. of mensurable music. The system was even followed by the printers of the great editions of Orlando di Lasso and of Palestrina, the arrangement of the various parts being precisely the same as in those of the MS. now before us. Subsequently superseded by the use of part-books, from which each singer could sing his own part, it was not until the seventeenth century that full scores appeared; before then they are practically non-existent, even in MS. Though we know from the evidence of the Bologna, Trent, and Modena MSS., that the early school of composition of which Dunstable was the founder must have rapidly arrived at a high degree of elaboration, if not of perfection, the traces of it now to be found in this country are extremely slight. It is this fact which makes the Eton MS. so valuable, for the compositions it contains are without exception by Englishmen, several of whom, as I shall presently hope to show, were men of high reputation in their day. So rare have collections of this sort become, that I believe I am right in saying that there are now in England only two other MSS. of the kind which, for size and importance of their contents, can at all compare with the Eton volume. These are respectively preserved in the Libraries of Lambeth Palace and of Caius College, Cambridge, both dating from a little later than the Eton book.