(_The Pinacotheca._) Formed by Pius VII. As the artist's name and the subject are painted on the frame of each picture (a hint some of the other galleries might adopt), it will be only necessary to mention the most important. FIRST ROOM.--The Christian Mysteries, one of Raphael's earliest paintings; Faith, Hope, and Charity, three medallions, by Raphael; Doubting Thomas, by Guercino; Marriage of S. Catherine of Alexandria with the Infant Christ, by Murillo; Adoration of the Shepherds, by Murillo. SECOND ROOM.--The Last Communion of S. Jerome, by Domenichino; Madonna di Foligno, by Raphael; The Transfiguration, Raphael's masterpiece. THIRD ROOM.--S. Sebastian, by Titian; The Assumption of the Virgin, in two parts--the Crowning, by Giulio Romano, and the Apostles round the Tomb, by Francesco Penni; Virgin and Child, by Sassoferrato; The Entombment, by Caravaggio. FOURTH ROOM.--S. Peter's Crucifixion, by Guido; Annunciation, by Baroccio; Christ Enthroned, by Correggio. THE MOSAIC MANUFACTORY. _Orders must be obtained from the Rev. Monsignor Fiorani, at the Sacristy._ _It is entered by a corridor from the ground floor at the left-hand corner of the Court of S. Damaso._ The mosaics in S. Peter's, S. Paul's, and other churches, were manufactured here. Some mosaics take a long time to execute, as great patience and art are required in blending the shades, &c., upwards of 27,000 different shades of the coloured _vetri_ being kept in stock. A plate, generally of metal, of the required size, is first surrounded by a margin rising about three-quarters of an inch above the surface. A mastic cement, composed of powdered stone, lime, and linseed oil, is then spread over as a coating, perhaps a quarter of an inch in thickness. When set, this is again covered with plaster-of-Paris rising to a level with the margin, upon which is traced a very careful outline of the picture to be copied, and just so much as will admit of the insertion of the small pieces of smalto or glass is removed from time to time with a fine chisel. The workman then selects from the trays, in which are kept thousands of varieties of colour, a piece of the tint which he wants, and carefully brings it to the necessary shape. The piece is then moistened with a little cement, and bedded in a proper situation, the process being repeated until the picture is finished, when the whole, being ground down to an even face and polished, becomes an imperishable work of art. The process is the same for making the small mosaics so much employed at the present day for boxes, covers, or articles of jewellery, and this work is sometimes upon almost a microscopic scale. The Florentine mosaic, which is chiefly used for the decoration of altars and tombs, or for cabinets, tops of tables, coffers, and the like, is composed of precious materials, in small slices or veneers, and by taking advantage of the natural tints which characterize the marble, the agate, or the jasper,