WHO does not know Turners picture of the Golden Bough? The scene, suffused with the golden glow of imagination in which the divine mind of Turner steeped and transfigured even the fairest natural landscape, is a dream-like vision of the little woodland lake of Nemi Dianas Mirror, as it was called by the ancients. No one who has seen that calm water, lapped in a green hollow of the Alban hills, can...