Tonalism and Whistler

whistler, originally uploaded by nrillustration.

I'm taking a class on Tonalist painting right now so was browsing some of James McNeill Whistler's work. Tonalism is a turn-of-the-century American painting style conjuring atmospheric landscapes using limited tones (thus the name). Whistler was a major proponent of Tonalism and I'm particularly struck by the paintings here:
left-Nocturne in Black and Gold: The Falling Rocket
right-Nocturne: Blue and Gold - Old Battersea Bridge