His passion for twisting movement

Dürer's water-colour drawing shows a column of black water, without weight or movement, standing over a peaceful landscape, while the other waterspouts hang like dark aprons in the distant sky. It is a conception at the furthest remove from Leonardo. Compared to Dürer's account of his dream, his very natural fear for his own safety, his pious prayer to God, Leonardo seems to glory in the triumph of natural forces and to dwell with gusto on every detail of destruction. His descriptions of the Deluge are found as early as the Ashburnham Codex of 1494 and as late as MS. G, but the most famous of them is on a sheet at Windsor, 12,665, where, on the pretext of instructing the painter how to represent a storm (the sheet is headed come si deve figurare una fortuna) Leonardo gives free rein to his imagination. Parts of this passage are literary and dramatic.

You might see on many of the hill-tops terrified animals of different kinds collected together and subdued to tameness, in company with men and women who had fled there with their children. The waters which covered the fields were strewn with tables, bedsteads, boats and various other contrivances made from necessity and the fear of death, and on these were men and women with their children, weeping, terrified by the fury of the winds which, with tempestuous violence, rolled the waters under and over and about the bodies of the drowned. Nor was there any object lighter than the water which was not covered with a variety of animals, among them wolves, foxes, snakes and others which, having come to a truce, stood together in a frightened crowd seeking to escape death.

You might have seen assemblages of men who, with weapons in their hands, defended the small spots that remained to them against lions, wolves and beasts of prey who sought safety there. Ah! what dreadful noises were heard in the air rent by the fury of the thunder and the lightnings it flashed forth, which darted from the clouds dealing ruin and striking all that opposed its course. Ah! how many you might have seen closing their ears with their hands to shut out the tremendous sounds made in the darkened air by the raging of the winds mingling with the rain, the thunders of heaven and the fury of the thunder-bolts.

Other parts of his description are more closely connected with his studies of moving water, and dwell on that aspect of the Deluge which appealed to his sense of form.

Let there be first represented the summit of a rugged mountain with valleys surrounding its base, and on its sides, let the surface of the soil be seen to slide, together with the small roots of the bushes, denuding great portions of the surrounding rocks. And descending ruinous from these precipices in its boisterous course, let it dash along and lay bare the twisted and gnarled roots of large trees turning up their roots; and let the mountains, as they are scoured bare, discover the profound fissures made in them by ancient earthquakes. The base of the mountains may be partly covered with ruins of shrubs, and these will be mixed with mud, roots, boughs of trees, and with all sorts of leaves thrust in with the mud and earth and stones. Into the depth of some valley may have fallen the fragments of a mountain damming up the swollen waters of its river; which, having already burst its banks, will rush on in monstrous waves; and the greatest will strike upon and destroy the walls of the cities and farmhouses in the valley. Then the ruins of the high buildings in these cities will throw up a great dust, rising up in shape like smoke or wreathed clouds against the falling rain. But the swollen waters will sweep round the pool which contains them striking in eddying whirlpools against the different obstacles, and leaping into the air in muddy foam; then, falling back, the beaten water will again be dashed into the air. . . .

The drawings at Windsor in which Leonardo illustrates these visions are the most personal in the whole range of his work. They express, with a freedom which is almost disturbing, his passion for twisting movement, and for sequences of form fuller and more complex than anything in European art. They are so far from the classical tradition that our first term of comparison might be one of the great Chinese paintings of cloud and storm, for example, the Dragon Scroll in the Boston Museum. Only in Oriental art do we find a similar mastery of the convention, by which forces and directions are reduced to visible linear curves. Yet, as with his landscape, closer study shows that Leonardo's scientific attitude has given his drawings a character fundamentally different from Chinese painting.