in Thoreau’s Journal:

Our Vernal lakes have a beauty to my mind which they would not possess if they were more permanent. Everything is in rapid flux here, suggesting that nature is alive to her extremities and superficies. Today we sail swiftly on dark rolling waves or paddle over a sea as smooth as a mirror, unable to touch the bottom, where mowers work and hide their jugs in August, coasting the edge of maple swamps where alder tassels and white maple flowers are kissing the tide that has risen to meet them. But this particular phase of beauty is fleeting. Nature has so many shows for us, she cannot afford to give much time to this. In a few days, per chance, these lakes will have runaway to the sea.

Such are the pictures which she paints. When we look at our masterpieces we see only dead paint and its vehicle, which suggests no liquid life rapidly flowing off from beneath. But in nature it is constant surprise and novelty…