In other volumes of this series we have learned how the churches, palaces, and public buildings were filled with paintings.[3] We shall now see that sculpture also contributed much to the adornment of the cities. Statues, busts, and bas-reliefs, in marble, bronze, and terra-cotta, ornamented many buildings both without and within. Our illustration shows two panels from the series of twelve bronze reliefs on the front of a church altar. Two little boy angels are making music with their pipes. The companion panels are also filled with musical angels, some singing and others playing on various instruments. The New Testament begins and ends with the music of angels. The birth of Jesus is heralded by a multitude of the heavenly host singing "Glory to God in the highest." The golden city of St. John's vision is filled with "the voice of harpers, harping with their harps," in the new song before the throne of God. Thence has arisen the beautiful custom of artists to represent angels as musicians. The child angels of our picture have tiny pointed wings as a sign of their heavenly origin. Certainly we cannot imagine such buoyant little creatures treading the earth like mortals. One stands on tip-toe like a bird poised for flight. The other skips through the air with joyous motion. The head of one is encircled by a halo, the emblem of purity. The other wears a fillet of flowers over his curls. Each carries two little pipes, the simplest of musical instruments. [Illustration: MUSICAL ANGELS (DONATELLO) Church of San Antonio, Padua] It was long ago in the childhood of the race that some shepherd, plucking a reed from the bank of a stream, first found that the hollow stem had a voice of its own. The pipe thereafter became a favorite instrument among primitive people. We read in the Old Testament Scriptures that the ancient Hebrews used it in the celebration of their festivities. At the Greek festivals also the pipers had a place in the procession of musicians. Our angel pipers are blowing lustily with puffing cheeks-- "Such sweet Soft notes as yet musician's cunning Never gave the enraptured air." They are genuine musicians, not children playing with the pipes as with toys. They move to the rhythm of their piping, their lifted faces expressing their delight. Their thin garments cling to their figures, and the loose ends flutter about them. Every line of the modelling is beautiful, the poise of the figures full of rhythmic grace. The angel at the left stands in profile, with face slightly turned away from the spectator. The right hand figure skips directly out of his panel, swinging lithely about towards the left, as he moves. The outlines of both figures describe long fine curves, with which the edges of the drapery run parallel. In the drawing of the right hand angel we may trace delicate patterns of interlacing ovals.