[Footnote 15: This is on the authority of a French writer, A. Jourdain, quoted by William H. Tillinghast in an essay on the "Geographical Knowledge of the Ancients," in the _Narrative and Critical History of America_. In the same essay an anonymous poem of the thirteenth century is quoted to show the prevalent belief in the sphericity of the earth.] [Footnote 16: In Didron's _Christian Iconography_, several interesting illustrations from old miniatures, etc., show the globe in the hand of the Creator. It is curious that this supposedly exhaustive authority on church symbolism gives no account of the origin and history of this emblem.] [Footnote 17: See Madonna pictures by Raphael, Titian, Correggio, and Michelangelo in other volumes of the Riverside Art Series.] [Footnote 18: _Eps_, with the curious mark above, stands for _episcopus_.] V BOYS WITH CYMBALS BY LUCA DELLA ROBBIA The bas-relief of our illustration is one of a series of marble panels designed to ornament the singing-gallery of a church. The children moving forward with song and cymbal remind us of the bands of singers and musicians who took part in religious processions of ancient times. We read of such processions among both the Greeks[19] and the Hebrews. [20] The custom of singing was adopted by the Christian church from its foundation,[21] and gradually the musical part of the service was developed into a fine art. There was a famous system of choral chanting under Pope Gregory I.,[22] and in the eleventh century part singing was introduced. At length the organ came into use, and by the fifteenth century it had become an important part of the church furnishings. It was early in this century when the wardens of the cathedral at Florence had an organ constructed on what the old writer Vasari called "a very grand scale." In connection with this an organ loft, such as the Italians call a _cantoria_, was needed to accommodate the singers. The Florentine sculptor, Luca della Robbia, received the order for this work, and was occupied with it some nine years (1431-1440). The cantoria is entirely of marble, built like a balcony, with the upper part or balustrade supported on five consoles or brackets. Four square bas-reliefs, separated by pilasters, ornament the front of the balustrade, and four more fill the corresponding spaces below, separated by the consoles. The artist took as the motive of his decorative scheme the one hundred and fiftieth psalm. This hymn of praise furnished his imagination with a series of pictures illustrating many kinds of music. The entire psalm is quoted in the Latin version on the gallery, the inscriptions running in narrow bands across the top and bottom and between the two rows of panels. These are the verses in the familiar English version of King James, grouped in the three sections into which they are divided:--