No one ever painted watercolors like the English. That cosseted landscape with its succulent meadows, venerable oaks and elms, its hedgerows, streams, and gently unfolding vistas; those noble cloudscapes shot through with light, are subjects, as the author says, well suited to watercolor; just as watercolor, with its freshness and delicacy, is the happiest medium for rendering air and light and cultivated nature.

In its beginnings the art was a far cry from the painterly lengths to which Turner took it, rendering pure light and little else. At first it was employed in accurate topograhical impressions of country sensitive perspective drawings in pen or pencil, enlivened by small genre figures, and delicately sweetened with transparent color washes.

In a long, illuminating essay, where he discusses the masters, Sandby, Rowlanson, Blake, Cozens, Girtin, Cotman, Constable, Bonington, Turner, and some of their distinguished disciples, Andrew Wilton shows how the medium evolved from these origins as an expressions of artistic purpose, different in the case of each of the 170 paintings represented, 58 of them happily in color - among these a sketch of Sandby's charming little studio with a tender spring sky full of birds, people at work in the next door garden, and maids busy in the courtyard; some Blakes, with their visionary white figures (looking skinned, someone said) floating in an atmosphere of lovely pinks and blues and greens; a stunning romantic view in the Alps by Francis Towne - huge abstract blue shapes occupying most of the paper, with a rim of sun-gilded peaks at the dismasted brig in a heavy grey sea, with a vault of stormy blue sky above - a picture that seems the work of an inspired instant; Robinson's magical mountains in the highlands, among threatening clouds and at their feet tiny figures of people and animals, birds, a puff of smoke, illuminated by stormy silver light; Turner's Caernarvon Castle in the lumimous gold, violet, and green haze of warm summer evening, with girls bathing from a boat. It's nice to note that Paul Mellon collected some of the gemsillustrated and they can be seen at Yale. (Phaidon, $24.95)

Eve Auchincloss