In the history of nineteenth-century landscape painting in the United States, the Luminists are distinguished by their focus on atmosphere and light. The accepted view of Luminist paintings is that they are basically spiritual and imply a tranquil mysticism that contrasts with earlier American artists' concept of nature as dynamic and energetic. According to this view, the Luminist atmosphere, characterized by "pure and constant light," guides the onlooker toward a lucid transcendentalism, an idealized vision of the world. What this view fails to do is to identify the true significance of this transcendental atmosphere in Luminist paintings. The prosaic factors that are revealed by a closer examination of these works suggest that the glowing appearance of nature in Luminism is actually a sign of nature's domestication, its adaptation to human use. The idealized Luminist atmosphere thus seems to convey, not an intensification of human responses to nature, but rather a muting of those emotions, like awe and fear, which untamed nature elicits. One critic, in describing the spiritual quality of harbor scenes by Fitz Hugh Lane, an important Luminist, carefully notes that "at the peak of Luminist development in the 1850s and 1860s, spiritualism in America was extremely widespread." It is also true, however, that the 1850s and 1860s were a time of trade expansion. From 1848 until his death in 1865, Lane lived in a house with a view of the harbor of Gloucester, Massachusetts, and he made short trips to Maine, New York, Baltimore, and probably Puerto Rico. In all of these places he painted the harbors with their ships – the instruments of expanding trade. Lane usually depicts places like New York Harbor, with ships at anchor, but even when he depicts more remote, less commercially active harbors, nature appears pastoral and domesticated rather than primitive or unexplored. The ships, rather than the surrounding landscapes – including the sea – are generally the active element in his pictures. For Lane the sea is, in effect, a canal or a trade route for commercial activity, not a free powerful element, as it is in the early pictures of his predecessor, Cole. For Lane nature is subdued, even when storms are approaching; thus, the sea is always a viable highway for the transport of goods. In sum, I consider Lane's sea simply an environment for human activity – nature no longer inviolate. The luminescence that Lane paints symbolizes nature's humbled state, for the light itself is as docile as the Luminist sea, and its tranquility in a sense signifies no more than good conditions on the highway to progress. Progress, probably even more than transcendence, is the secret message of Luminism. In a sense, Luminist pictures are an ideological justification of the atmosphere necessary for business, if also an exaggerated, idealistic rendering of that atmosphere.