It was the opinion of Leonardo that the temporary nature of music caused its inferiority to painting. Although durability was in itself no absolute test,--else the work of coppersmiths would be the highest art,--yet in any final scale, permanence could not altogether be disregarded. Music perished in the very act of its creation, {xviii} while painting preserved the beautiful from the hand of time. "Helen of Troy, gazing in a mirror, in her old age, wondered how she had twice been ravished." Mortal beauty would thus vanish, if it were not rescued by art from destroying age and death. Leonardo contrasted painting with sculpture, for he had practised both, and thought himself peculiarly qualified to judge their merit. He considered the former the nobler art of the two, for sculpture involved bodily toil and fatigue, while by its very nature it lacked perspective and atmosphere, colour, and the feeling of space. Painting, on the other hand, caused by an illusion, was in itself the result of deeper thought. An even broader test served to convince him of its final superiority. That art was of highest excellence, he wrote, which possessed most elements of variety and universality. Painting contained and reproduced all forms of nature; it made its appeal by the harmonious balance of parts which gratified all the senses. By its very duality it fulfilled the highest purpose. The painter was able to visualize the beauty which enchanted him, to bring to reality the fancy of his dreams, and give outward expression to the ideal within.