Cornelius Varley devoted most of his life to scientific instrument making. In the first decade or so of the nineteenth century however, he was equally active as an artist. This watercolour was made on a visit to Wales in 1805, when he also wrote detailed descriptions of atmospheric phenomena. In one account he traced 'the gradual progress from a cloudless morning to universal rain' in the region of Snowdon. Varley combined his precise observation of nature with a personal, almost spiritual interpretation of the landscape, which he expressed by eliminating detail to create an effect of mystery and grandeur.