Peter Lanyon was the only native-born Cornishman among the leading figures of the . He studied at Penzance School of Art 1936-7 and then spent four months at the in 1938. He met Nicholson, Hepworth and Gabo when they arrived in Cornwall at the outbreak of war in 1939, received twice-weekly lessons from Nicholson for a time and was much encouraged by Gabo. He made constructions during the war, but afterwards increasingly developed a based art in both and constructions which provides one of the touchstones of the St Ives approach. The writer and poet David Lewis has recorded how in the years 1950 and 1951 Lanyon 'began a journey into a landscape-seascape experience that became utterly his own and consuming' and quotes Lanyon's own words: 'The sea then became something which was down towards my feet ... as I looked out from the beach. I then walked over the Western Hill ... I lay down and looked over the edge and watched the sea coming in ... I came back ... under the lea and the shelter, and there I sat down in the grass ... the sun began to come out at that time and the grass blew and the sea and the sky became bluer.' Lanyon goes on to describe his ambition to make paintings as 'a recreation of experience in immediacy, a process of being, made now.' This recreation would be through a free gesture 'The mark of hand and arm ... extracted from a soil-based and rooted knowledge.' 'Thermal' with its fluid swirls and strokes of paint, clear light and intense colour, evoking not so much sea, sky and cloud as the artist's sensation of them, is an example of this painting at its most assured. It dates from after Lanyon's discovery of gliding which became a passion, giving him a new view of the landscape he loved. He wrote: 'The experience in "Thermal" does not only refer to glider flight. It belongs to pictures which I have done before e.g. "Bird-Wind" and which are concerned with birds describing the invisible, their flight across cliff faces and their soaring activity ... The picture refers to cloud formation and to a spiral rising activity which is the way a glider rises in an up-current. There is also a reference to storm conditions and down currents. These are all things that arise in connection with thermals.'
Lanyon had a one-man exhibition in New York in 1957 which was well received and became friends with Mark Rothko, whom he brought to St Ives in 1958. Like others of the St Ives School his work with its emphasis on gesture and the expression of inner feeling in purely terms has much in common with . Lanyon died as a result of a gliding accident in 1964.
Simon Wilson, Tate Gallery: An Illustrated Companion, Tate Gallery, London, revised edition 1991, p.225