Among the aspects of Jacob van Ruisdael's work that interested Constable was the Dutch painter's frequent use of a low horizon line. In 1819, Constable measured the proportion of land to sky in several Dutch landscapes in a London exhibition. In this view of Hampstead Heath, the main subject is the sky and its looming storm clouds. Unlike Ruisdael's sweeping, panoramic compositions, Constable here has chosen to emphasize the rising, mound-like shape of the land. [Philadelphia Museum of Art - Oil on paper, mounted on canvas, 30.8 x 51.1 cm]