The idea of the Macrocosm, then, which presents itself in the style- problem as simplified and capable of treatment, poses a multitude of tasks for the future to tackle. To make the form-world of the arts available as a means of penetrating the spirituality of entire Cultures— by handling it in a thoroughly physiognomic and symbolic spirit—is an undertaking that has not hitherto got beyond speculations of which the inadequacy is obvious. We are hardly as yet aware that there may be a psychology of the metaphysical bases of all great architectures. We have no idea what there is to discover in the change of meaning that a form of _pure extension_ undergoes when it is taken over into another Culture. The history of the column has never yet been written, nor have we any notion of the deeply symbolic significances that reside in the means and the instruments of art. Consider mosaic. In Hellenic times it was made up of pieces of marble, it was opaque and corporeal-Euclidean (e.g., the famous Battle of Issus at Naples), and it adorned the floor. But with the awakening of the Arabian soul it came to be built up of pieces of glass and set in fused gold, and it simply covered the walls and roofs of the domed basilica. This Early-Arabian Mosaic-picturing corresponds exactly, as to phase, with the glass-picturing of Gothic cathedrals, both being “early” arts ancillary to religious architectures. The one by letting in the light enlarges the church-space into world-space, while the other transforms it into the magic, gold-shimmering sphere which bears men away from earthly actuality into the visions of Plotinus, Origen, the Manichæans, the Gnostics and the Fathers, and the Apocalyptic poems.