The tenth Duke of Hamilton was one of the most distinguished bibliophiles of his time, and commenced purchasing whilst yet Marquis of Douglas. A large portion of his library was collected in Italy and various parts of the Continent, whilst the collection of Greek and Latin manuscripts which he obtained when on a diplomatic mission to Russia formed an unrivalled series of monuments of early art. In 1810 he married Susanna Beckford, and at her father's death the whole of his splendid library came into his possession. The two collections, however, were kept quite distinct. The Hamilton collection of printed books was sold at Sotheby's in May, 1884, the eight days realizing L12,892 12s. 6d. The most important feature of the library, however, was the magnificent collection of MSS. which the Prussian Government secured by private treaty--through the intermediary, it is understood, of the Empress Frederick--for L70,000. In May, 1889, those which the authorities decided not to retain for the Royal Museum at Berlin were transferred to Messrs. Sotheby's, and ninety-one lots realized the total of L15,189 15s. 6d. The gems of the collection were a magnificent volume of the Golden Gospels in Latin of the eighth century, formerly a gift to Henry VIII., which sold for L1,500--a London bookseller once offered L5,000 for this book--and a magnificent MS. of Boccaccio, 'Les Illustres Malheureux,' on vellum, 321 leaves, decorated with eighty-four exquisite miniatures, which sold for L1,700. It may be mentioned that a large number of the Beckford and Hamilton books were purchased through the late H. G. Bohn. [Illustration: _George John, Earl Spencer._] The Althorp Library, now in the possession of Mrs. Rylands, of Manchester, was formed by George John, Earl Spencer (1758-1834), between 1790 and 1820. Until its recent removal from Althorp it was the finest private library in existence. In 1790 Lord Spencer acquired the very fine and select library of Count Rewiczki, the Emperor Joseph's Ambassador in London, for about L2,500, and for the next thirty years the Earl was continually hunting after books in the sale-rooms and booksellers' shops. The story of the Althorp Library has been so repeatedly told, from the time of its first librarian, the devil-hunting Thomas Frognall Dibdin--whose flatulent and sycophantic records are not to be taken as mirroring the infinitely superior intellect and taste of his employer--down to the present day, that any further description is almost superfluous. Besides this, the library is one which will soon be open to all. We may, however, mention a point which is of great interest in the study of books as an investment. It may reasonably be doubted whether the Althorp Library cost its founder much over L100,000; it is generally understood that the price paid for it in 1892 was not far short of L250,000. [Illustration: _John, Duke of Roxburghe, Book-collector._]