The Notebooks of Leonardo da Vinci

establishing him as a thinker with very precise powers of analysis as well as a productive investigator whose work shows a firm grasp of the principles of experimental science. For example, among the anatomical investigations recorded in the Windsor Manuscripts is that of the spinal cord and intestines of the frog. ‘The frog,’ he says, ‘remains alive for several hours when the head, the heart, and all the intestines have been removed. And if you prick the said cord, it instantly twitches and dies’ (Quaderni V 21 r.). On the back of the same sheet is written: ‘the frog dies instantly when the spinal cord is pierced; and before this, it lived without a head, without a heart, or any bowels, intestines, or skin; and here, therefore, it would seem, lies the foundation of movement and life.’

The originality of his methods of anatomical investigation is illustrated by the details he provides regarding the making of wax casts in order to discover the true shape of the ventricles of the brain:

‘Make two air holes in the horns of the great ventricles and insert melted wax by means of a syringe, making a hole in the ventricle of the memoria; through this hole, fill the three ventricles of the brain. Afterwards, when the wax has set, remove the brain and you will see the shape of the three ventricles exactly. But first, insert thin tubes into the air holes so that the air within these ventricles may escape and thus make room for the wax entering the ventricles’ (Quaderni V 7 r.).

Leonardo, as the learned editors of the Quaderni d’Anatomia inform us, was the first to make casts of the cerebral ventricles, and several hundred years passed before the idea occurred to any other anatomist.

It is on the edge of this unexplored knowledge that his gift of expression often lingers and teases us with its beauty.

‘Every weight tends to fall toward the center by the shortest path’ (C 28 v.) is the core of Newton’s law of gravitation. ‘The earth is moved from its position by the weight of a tiny bird resting upon it. The surface of the sphere of water is moved by a tiny drop of water falling upon it’ (B.M. 19 r.). Is this also the language of mechanics?

In the section of his treatise on ‘Painting,’ in which he compares painting with the other arts, he has no divided loyalty; but in ‘the Prophecies,’ he has expressed his sense of the potential of literature, though somewhat cryptically: ‘Feathers