The seraphim immediately surround the throne of God, and are ever lost in adoration and love, which is expressed in their very name, seraph coming from a Hebrew root, meaning love. The cherubim also worship the Creator, and are assigned to some special duties; they are superior in knowledge, and the word cherub, also from the Hebrew, signifies to know. Thrones sustain the seat of the Almighty. The second hierarchy governs the elements and the stars. Princedoms protect earthly monarchies, while archangels and angels are the agents of God in his dealings with humanity. The title of angel, signifying a messenger, may be, and is, given to a man bearing important tidings. Thus the Evangelists are represented with wings, and John the Baptist is, in this sense, an angel. The Greeks sometimes represent Christ with wings, and call him “The Great Angel of the Will of God.” Very early in the history of Art a system of religious symbolism existed, a knowledge of which greatly enhances the pleasure derived from representations of sacred subjects. In no case was this symbolism more carefully observed than in the representations of angels. The aureole or nimbus is never omitted from the head of an angel, and is always, wherever used, the symbol of sanctity. Wings are the distinctive angelic symbol, and are emblematic of spirit, power, and swiftness. Seraphim and cherubim are usually represented by heads with one, two, or three pairs of wings, which symbolize pure spirit, informed by love and intelligence; the head is an emblem of the soul, the love, the knowledge, while the wings have their usual significance. This manner of representing the two highest orders of angels is very ancient, and in the earliest instances in existence the faces are human, thoughtful, and mature. Gradually they became child-like, and were intended to express innocence, and later they degenerated into absurd little baby heads, with little wings folded under the chin. These in no sense convey the original, spiritual significance of the seraphic and cherubic head. The first Scriptural mention of cherubim with wings occurs after the departure of the Israelites from Egypt, Exodus xxv., 20: “And the cherubim shall stretch forth their wings on high, covering the mercy seat.” Isaiah gives warrant for six wings, as frequently represented in Art, and so vividly described by Milton: “A seraph winged; six wings he wore to shade His lineaments divine; the pair that clad Each shoulder broad, came mantling o’er his breast [Illustration: PERUGINO.--A SIX-WINGED CHERUB. (FROM THE ASSUMPTION OF THE VIRGIN.)] With regal ornament; the middle pair Girt like a starry zone his waist, and round Skirted his loins and thighs with downy gold And colors dipp’d in heaven; the third, his feet Shadow’d from either heel with feather’d mail, Sky-tinctured grain.”