The Courtauld Gallery's new exhibition, A Dialogue with Nature, takes its title from the German Romantic painter Caspar David Friedrich's description of drawing the natural world. This is a small show, of only 26 drawings, watercolours and oil sketches, but it is an intense one. The pictures demonstrate the ways landscape affected British and German artists of the period from the 1760s to the 1840s. 

The likes of Friedrich and Samuel Palmer were not interested in topography but in the natural world as a spiritual aid and an inspiration for the imagination. Landscape for them was essentially numinous ("God is everywhere," said Friedrich, "in the smallest grain of sand. I also wanted to show him in the reeds.") For late Turner the reality of a scene was merely a template on which to build or record painterly and atmospheric effects. Other artists, however, such as Constable and Johann Georg von Dillis, sought the essence of nature through accurately depicting clouds or trees. All in their different ways showed man's insignificance.

The exhibition is a collaboration between the Courtauld, with its holdings of British works, and the Morgan Library and Museum in New York, which has supplied the German pictures. These last are the most fascinating. German Romantic works are rare in Britain (there is only one Friedrich in the National Gallery and nothing by the extraordinary Philipp Otto Runge) so three drawings and watercolours by Friedrich and pictures by lesser but nevertheless distinctive artists, such as Karl Friedrich Lessing and Carl Philipp Fohr, represent riches.

"The artist should not only paint what he sees before him, but also what he sees in himself," said Friedrich and this goes to the heart of the Romantic landscape. The pictures here — small-scale, beautiful, saturated with feeling and the intensity of vision — are full of ruins, woods and moonlight; the places and atmospheres that in sensitive souls encourage reflection. We may know that such motifs are simple triggers to feeling, but the Romantic legacy remains potent and the 26 pictures in the show are thus self-portraits of their artists' sensibility in which we, Everyman, can still recognise ourselves.