A field of water betrays the spirit that is in the air. It is continually receiving new life and motion from above. It is intermediate between land and sky.

This description of Walden Pond from the chapter entitled “The Ponds” shows how insufficient the label “nature writer” is when applied to the mystical vision of Thoreau when he regards the landscape around him. It is true that he describes the flora and fauna of Concord with a level of vibrancy and specificity to which nature writers aspire, but he does more than merely observe and take notes. He also, at times, transforms the physical environment into a spiritual vision, with religious rather than practical or scientific meaning. Here the phrase “the spirit that is in the air” is more reminiscent of a preacher or poet than a naturalist. It is hard scientifically to define what exactly the “new life” is that comes to the water from the sky, but in a transcendental, intuitive, spiritual context it makes perfect sense. Even the description of the pond as an “intermediate between land and sky” has more of an allegorical meaning than a physical one, since in physical terms the pond is not between land and sky at all. Allegorically, the pond is the human soul at the juncture between earth and heaven, living in an earthly realm but reflecting a peaceful world above just as the pond reflects the sky. Thoreau makes this parallel almost explicit when he compares the depth of the pond to the depth of the soul.