beauty of nature. Rooted to one place like a tree, it shares the beauty of its site, and responds to the ever varying effects of light and shadow, rain and mist and snow. The abstract beauty of architecture can be understood without any knowledge of the purposes of buildings. A Hindu who knows nothing of our civilization cannot fail to be responsive to Notre Dame, any more than we can fail to admire the beauty of Taj Mahal. The very simplest architectural forms, like the pyramids or the Washington monument, provided they are of sufficient size and mass, speak an eloquent language which is immediately understood. And the content of their speech is not so abstract as might be judged from our previous studies of it; for in architecture, as in music, concrete emotions and sentiments flow into the channel cut by the form. Longing, aspiration, and mystery have universally been felt into a form pointing skyward; and the feeling of incompleteness has been lost, and security regained, in an overarching dome. There is, however, this difference between architecture and music. In music, the emotional content is purely personal; while in architecture, it may become social and historical. Architectural purposes are all social: the purposes of a family, a nation, a cult. And the purposes of the greatest of buildings--of those which serve the nation and religion--are also historical; about them gather the traditions of a community. Centers of the life of a people, created by it and enduring with it, they become its symbols; or outlasting it, memorials and witnesses to it. The vague emotions aroused by the architectural forms are pointed and enriched by this spirit: the vastness, seclusion, magnificence, mystery, and aspiration of the Gothic cathedral become associated with the life of the medieval Catholic church; the fine balance, clarity, and simplicity of the Greek temple with the best in Greek culture. This interpretation of a building in terms of its purpose and history is necessary to a complete aesthetic appreciation. Without it, a building may have many beauties, all the beauties which we have analyzed; but they are all separate, and there is no beauty of the whole. It is the life which the many parts and aspects serve that makes them into one. I shall close this chapter with a brief discussion of architectural composition. The unity of a building is constituted primarily by the necessary adjustment of part to part which makes possible the life that it incloses. How the parts serve this purpose is not immediately evident to intuition; nor can it be; yet it should be intelligible to a thoughtful study. The knowledge thus gained may then enter into an imaginative vision, for which the building will seem like an organism pulsing with life.