Turner did not begin oils until he was about twenty-one, his first exhibited oil-painting apparently being The Fishermen at Sea, off the Needles of 1796. It is typical of Turner to have begun the medium by attacking the difficult problem of moonlight. Profound as Turner's love of the mountains was, it was scarcely so fundamental as his love of the sea. He had been feeding his eyes on waves and storms, upon clouds and vapour. Here the value of his splendid visual memory is evident. A wave cannot be drawn slowly and stolidly; it will not sit still to have its portrait painted. For this reason most painters reduce their waves as a whole to a formula. Turner alone by constant observation and by a consequent thorough knowledge of wave forms and of the rules that they obey, has given to his seas mass and weight as well as movement. The sea in itself absorbed him, but especially the sea as it affected ships. To a sailor, and Turner was at heart a sailor, a ship is a living creature, courageous and loyal, resourceful, yet pathetically in need of help. Her curves, like those of a human figure, are beautiful because they are of use. In drawing ships Turner shows a knowledge that springs from love; his actual manual dexterity, which is always remarkable, being never more astonishing than when he is firmly yet delicately delineating masts and rigging. If Turner sympathised with ships, he sympathised equally with the men within them and loved to depict fishermen pulling at oars or sailors grappling with ropes. He only cared in fact to portray the mood of the sea as it affected the experiences of man. After his continental tour in 1802, his eyes seemed to have been opened to the beauty of a type of English scenery that he had hitherto neglected. Up till now he had painted mainly ruins, stormy seas, and frowning mountains, now he began to choose subjects from agricultural or pastoral country and often from scenes with trees and water. If the spirit of his earlier works was akin to Byron's, this new mood might be called Wordsworthian, though Turner had probably not read Wordsworth's poetry, but ratherwas inspired, like the poet, by the spirit belonging to the age. His greatest masterpieces of the period are Windsor and Sun Rising through Vapour. After over forty years of severe discipline as a draughtsman, his hold upon structure has began to relax; and he is now absorbed exclusively in rendering colour, light and atmosphere. The vast total quantity of Turner's work is one of the marks of his genius. (From English Painting from the 17th Century to the Present Day by Ch.Johnson)