Bringing out the hippy

Of all the subjects that have traditionally exercised the eyes and minds of artists, it is nature that gets the shortest shrift in contemporary art.

Richard Long - though in formal terms, very much a child of Sixties conceptualism - is somewhat old-fashioned. For more than 35 years Long, who won the Turner Prize in 1988, has been making art by walking in wilderness across the world and recording and evoking his journeys in photographs and terse wall texts, sculptures and simple paintings.

Together these works articulate a world view in which nature is an elemental force with which man has an instinctive emotional connection.

Unsurprisingly, for one who graduated from art school just in time for the Summer of Love, Long's vision owes much to hippy sensibilities, but also lays claim to the tradition of Romanticism (hippies are, after all, low-grade Romantics) and the far older cultural forms encompassed by animism.

Obviously such an attitude is markedly at odds with the amused cynicism of much contemporary work. It is a difference that serves to give his work a distinguished air, but also generates an interesting level of risk, for his creations function only if you are willing to tune into his wavelength.

The fact that the work does succeed says much for Long's ability to utilise and manipulate still-powerful, collectively held perceptions and clichés about our world.

In this exhibition, one wall text celebrates an eight-day walk in Galicia, another a walk in Brittany, both Celtic areas, while the photographs record his activities in India. All these locations are still redolent, despite masstourism and the general availability of Celtic bagpipe music, of the exotic and preternatural power.

Similarly, the two sculptural pieces here invoke ancient, symbolic stone works. Cornwall Slate Lines consists of two almost parallel lines of slate blocks that snake in gentle undulations from one corner of the gallery towards another.

In the gallery upstairs, the curves of an elliptical formation made from flint and chalk happily complement the circular wall-painting, whose form is the I-Ching hexagram for mountain, made with mud from the River Avon.

Strangely, these forms, like the wall texts, achieve a level of interest that exceeds their simplicity. They are among the few art objects that truly deserve to be called poetic, since they function on the same lines as poetry, generating aesthetic power from their constituent elements, while simultaneously deriving meaning, though imprecise, from the language from which they borrow. They also imply that most of us have a little hippy in our hearts.

Until 30 August. Information: 020 7495 5050.