Sometimes, as we see at Peterhouse, ancient usage asserted itself so far that a seat was contrived by making the plinth of the tall case project to a sufficient distance. These bookcases were set up between 1641 and 1648. _Bookcase in Peterhouse Library._ When the necessity for still further space for books became imperative, the seat was given up, or was dropped to the height of a step, as in the bookcases in the south room of the University Library, Cambridge, put up soon after 1649. The carved wing, however, which had masked the ends of it, was retained as an ornament, both there and in the old library at Pembroke College, Cambridge, furnished soon after 1690. Meanwhile a new system of arranging bookcases had come into use on the continent. So far as I have been able to discover, the first library arranged in the way with which we are familiar, namely, with the bookcases set against the walls instead of at right angles to them, is that of the Escurial. These cases were made by Herrera, the architect of the building, in 1584. There is no indication of chaining, but, in conformity with ancient usage, the fore edge of the books, instead of their backs, is turned outwards, and the desk is represented by a shelf, carried all round the room at a convenient height. No doubt so important a structure as this, erected by so mighty a potentate as the King of Spain, would be much talked about, and provoke imitators. Among these, I feel sure, was Cardinal Mazarin, whose library was fitted up in Paris in or about 1647, as a library to be used daily by the public. After his death his books and bookcases were moved to the building in which they may still be seen. I will now shew you views of the two libraries, and you shall decide whether it is not obvious that the one was suggested by the other. _Interior of the Library of the Escurial and of the Bibliotheque Mazarine, Paris._ The new system was not accepted hastily. I believe that Sir Christopher Wren, when he built Trinity College Library in 1695, was the first English architect who ventured to build a library with windows which, as he says himself, "rise high, and give place for the deskes against the walls." I suspect that he borrowed this latter idea from France, which he visited in 1665, and most likely from the Bibliotheque Mazarine, for he has himself recorded his admiration for "the masculine furniture of the Palais Mazarin," though he does not specially mention the library. But he did not discard the ancient arrangement altogether. On the contrary he utilised it so far as to subdivide the room, and provide recesses for the convenience of students. He says: