NARRATOR: This sketch dates from a period in Turner’s life in 1805, when he retreated from London and rented a house at Isleworth, to the west of London. Curator Amy Concannon. AMY CONCANNON: It’s a wonderful period in his work, this Thames period. He sketched and painted from the banks of the Thames or, crucially, from a little boat, and he would sometimes sleep in this little boat between stop offs on the Thames. It’s thought that this picture depicts Guildford Castle. Crucially what I think ‘Tree Tops and Sky’ shows is this intense period of experimentation that this period on the Thames became. It was when he was opening up his mind to new possibilities, particularly working outside in oil paint. This was not something that Turner did so often because the equipment required for painting out of doors at this time would involve at the very minimum things like spirit, linseed oil, brushes, a pallet, pencils, all kinds of paint, containers, boards, rags. So with so much paraphernalia it’s no wonder that Turner, who famously liked to travel light, didn’t want to be encumbered with all of that clunky equipment. But I think, happily for Turner, sketching in a boat on the River Thames enabled him to combine his favourite activity, painting, with his other favourite activity, fishing. So all in all it was a very happy time.