Molly Longlegs has remarkably long legs, even for a Newmarket champion. But these, together with her small head and big eyes, are what mark her out as a thoroughbred. They're the characteristics of the Arab stallions from which she's descended. So the artist, George Stubbs, can be forgiven for a bit of artistic license. Liverpool-born Stubbs is regarded as one of the greatest-ever painters of animals. He's captured Molly's every muscle, tendon and sinew. You can almost see the blood pumping through her veins. His understanding of anatomy was the result of observation. This was the Age of Enlightenment, with its philosophy that knowledge comes from the study of nature, guided by reason. Stubbs spent a year and a half dissecting and drawing horses, holed up in a Lincolnshire farmhouse. He eventually published the results in 1766, a few years after this painting. His scientific approach appealed to a circle of London aristocrats who had a passion both for science and art - and for horseracing and breeding, itself a scientific experiment. One of these, Lord Bolingbroke, was Molly's owner and one of Stubbs' first patrons. But Molly's so much more than a textbook study. Her laid-back ears and flashing eyes hint at her highly-strung character. And the jockey's an individual too, even though we don't know who he is. Stubbs' patrons had huge respect for their jockeys' skills. So he was particularly interested in conveying the relationship between jockey and horse. Stubbs was also a superb painter of delicate landscapes, as you can see. In all his work he insisted nature was 'superior to art'. But his compositions nevertheless have harmony. This painting's like a classical frieze - with the careful balance of three pairs of feet, and tiny pinpricks of light on shoe-nail, bridle and button. On this wall you'll find other Stubbs pictures demonstrating his inventiveness, imagination, interest in the exotic and sense of humour. 'Horse Frightened by a Lion' started a whole new type of painting - animal terror. And there's the massive Lincolnshire Ox - which eventually collapsed and died under its own weight.