And it renders the dilemma, or multilemma, more embarrassing, that whatever teaching is to be had from the founders and masters of art is quite unpractical. The first source from which we should naturally seek for guidance would, of course, be the sayings of great workmen; but a sorrowful perception presently dawns on us that the great workmen have nothing to say. They are silent, absolutely in proportion to their creative power. The contributions to our practical knowledge of the principles of Art, furnished by the true captains of its hosts, may, I think, be arithmetically summed by the +O+ of Giotto: the inferior teachers become didactic in the degree of their inferiority; and those who can do nothing have always much to advise. 36. This however, observe, is only true of advice direct. You never, I grieve to say, get from the great men a plain answer to a plain question; still less can you entangle them in any agreeable gossip, out of which something might unawares be picked up. But of enigmatical teaching, broken signs and sullen mutterings, of which you can understand nothing, and may make anything;--of confused discourse in the work itself, about the work, as in Duerer's Melancolia;--and of discourse not merely confused, but apparently unreasonable and ridiculous, about all manner of things _except_ the work,--the great Egyptian and Greek artists give us much: from which, however, all that by utmost industry may be gathered, comes briefly to this,--that they have no conception of what modern men of science call the "Conservation of forces," but deduce all the force they feel in themselves, and hope for in others, from certain fountains or centers of perpetually supplied strength, to which they give various names: as, for instance, these seven following, more specially:-- 1. The Spirit of Light, moral and physical, by name the "Physician-Destroyer," bearing arrows in his hand, and a lyre; pre-eminently the destroyer of human pride, and the guide of human harmony. Physically, Lord of the Sun; and a mountain Spirit, because the sun seems first to rise and set upon hills. 2. The Spirit of helpful Darkness--of shade and rest. Night the Restorer. 3. The Spirit of Wisdom in _Conduct_, bearing, in sign of conquest over troublous and disturbing evil, the skin of the wild goat, and the head of the slain Spirit of physical storm. In her hand, a weaver's shuttle, or a spear. 4. The Spirit of Wisdom in _Arrangement_; called the Lord or Father of Truth: throned on a four-square cubit, with a measuring-rod in his hand, or a potter's wheel. 5. The Spirit of Wisdom in _Adaptation_; or of serviceable labor: the Master of human effort in its glow; and Lord of useful fire, moral and physical.