 Hello, I'm Stephen Parkin and I'm one of the curators on the British Libraries Exhibition on Leonardo, along with my colleague Andrea Clark and Giuliana Barroni from Birkbeck College in the University of London. The manuscripts that we put together in the exhibition show us the extraordinary range of his working methods, the experimental way that he approached the observation, the analysis and the understanding of nature. In the Codex Leicester we have drawings which show him inventing devices to measure the speed and the current of water flow. There are also thought experiments where that he is sort of thinking through something and he does that in his notebooks on paper and we can see Leonardo thinking a possibility, a hypothesis through. What I wanted to point out here in terms of the themes of the exhibition, which as we've said is studying water in motion, but motion more generally also in terms of human bodies and human facial features, is Leonardo's interest in hair and in the way it moves and in the way it curls and in particular this head of lader at the bottom where the spirals of her curls of her platted hair are studied with extraordinary detail. If we refer back for a moment to the Codex Leicester, the treatise on water he was preparing and if we look at the small drawings in the margin of the Codex Leicester, here we see how the obstacle, the rectangular obstacle which is placed in the water flow creates again curls and spirals in the flow of the current as it tries to get past the obstacle. Putting the drawings together with the drawings in the Codex Leicester show us how Leonardo was interested in what connected multiple natural phenomena, the underlying patterns of natural phenomena and also how his interest in motion affected his work as a painter.