In considering this great feature, the most noteworthy characteristic of Umbrian art, it is impossible to avoid reference to Mr. Bernhard Berenson's pages and to his definition of what he terms "space composition," which he defines in this way: "Space composition differs from ordinary composition in the first place most obviously in that it is not an arrangement to be judged as extending only laterally, or up and down, on a flat surface, but as extending inwards in depth as well. It is composition in three dimensions and not in two, in the cube and not merely on the surface."[E] Farther on he remarks: "This art comes into existence only when we get a sense of space not as a void, as something merely negative such as we customarily have, but on the contrary as something very positive and definite, able to confirm our consciousness of being, to heighten our feeling of vitality." It is the wonderful art of space compositions which so distinguishes Perugino from his Sistine Chapel days down to the end of his life. The power is so well expressed by Mr. Berenson that nothing is needed to further define it but he still further emphasises "space composition" when he states that it is an "intrinsically religious art" capable of "communicating the religious emotion" and able to "awaken in those who looked at the pictures a consciousness of preference for a life holy and refined." In this first great picture "Christ giving the Keys to St. Peter," all the power of this marvellous capability is at once apparent. It produces a sense of vastness, of spaciousness, of broad, free, open air enclosed only by the blue arch of Heaven, and therefore gathers up and retains all the higher emotions of the spectator. There are the grand figures in the foreground, majestic and wonderful in their dignity; beyond them are others in the receding distance, smaller and smaller as the eye notes the vast distance expressed in the picture. In the centre rises the wonderful temple. Bramantesque and stately, and beyond it, disappearing away into the horizon are the everlasting hills that bound and yet seem to extend the broad space of the Umbrian landscape the utmost distance of which is lost in the blue haze of the sky. The two triumphal arches at the sides serve to emphasise the great space that the picture embraces and the effect is that of gazing through an open window in Perugia or at Montefalco. There is no sense of crowding, the space is so vast that the populace of a country could not crowd it, and the air circulates in and around every group and serves to give the greater _plein-air_ charm. There is a soothing quiet about the whole, a self-restraint and a stillness, and even though figure stands apart from figure and each one hardly notices the other, yet there is a fine thread of common interest to be seen connecting the whole of the foreground group and linking the spectators to the two central persons, Christ and the Foundation of His Church. [Illustration: