It numbers some splendid apartments, containing many works of art; and the gardens are of considerable extent. It is the residence of King Humbert, and is accessible to the public; but should the royal family be at home, the private apartments are not shown; otherwise it may be readily viewed on presenting your card at the entrance. Guido Reni's beautiful picture of the Annunciation is in the small private chapel, as also the frescoes of the life of the Virgin, by Albani. The casino in the gardens is decorated with frescoes by Oritonti, Battoni, and Paolini. The palace was founded by Gregory XIII. in the year 1574, and completed by Clement X., several intermediate popes having done much for its extension and embellishment, notably Clement VIII. Urban VIII. enclosed and added the present garden, and Gregory XVI. and Pius IX. made the palace what it is--that is to say, one of the most sumptuous and attractive palaces in Italy. Few of our readers will require to be informed that the Quirinal was the place appointed for the conclave when the new Pope was elected, and that Pope Pius IX. was the last successor of S. Peter who was proclaimed from the balcony overhanging the principal entrance. _On the left, beyond the fountain, within the high wall, is the_ ROSPIGLIOSI PALACE. _Open on Wednesdays and Saturdays from 9 till 3; entrance upstairs to left of gate._ It is celebrated for its casino, containing Guido Reni's Aurora; it also contains many pictures, ancient sculptures, and fragments of frescoes, from the Baths of Constantine, on a portion of the site of which it is built. The principal paintings in the palace are:-- CENTRE ROOM.--Head of Christ, by Jesse; Vanity, by Titian; Mater Doloroso, by Sassoferrato. LEFT ROOM.--Our Saviour Bearing the Cross, by Daniele da Volterra; Head of Goliath, by Domenichino; the Deposition, a sketch by Rubens; Perseus Rescuing Andromeda, by Guido Reni. RIGHT ROOM.--Diana and Venus, by Lawrence Lotto; Adam and Eve, by Domenichino; Samson's Death, by Caracci. _Opposite is the entrance to_ THE COLONNA GARDENS. They contain several antiques and remains of the cornice of Aurelian's Temple of the Sun. Looking down a chasm, we see remains of the Baths of Constantine. Under the cypress trees are several sarcophagi, and the stem of the pine tree planted on the day Rienzi died. There is also a fine piece of the tufa wall that made the seven hills one city. THE CAPITOLIUM VETUS.