re where you
can see the sand, then a light green, which gradually deepens to a
uniform dark green in the body of the pond. In some lights, viewed even
from a hilltop, it is of a vivid green next the shore. Some have
referred this to the reflection of the verdure; but it is equally green
there against the railroad sand-bank, and in the spring, before the
leaves are expanded, and it may be simply the result of the prevailing
blue mixed with the yellow of the sand. Such is the color of its iris.
This is that portion, also, where in the spring, the ice being warmed by
the heat of the sun reflected from the bottom, and also transmitted
through the earth, melts first and forms a narrow canal about the still
frozen middle. Like the rest of our waters, when much agitated, in clear
weather, so that the surface of the waves may reflect the sky at the
right angle, or because there is more light mixed with it, it appears at
a little distance of a darker blue than the sky itself; and at such a
time, being on its surface, and looking with divided vision, so as to
see the reflection, I have discerned a matchless and indescribable light
blue, such as watered or changeable silks and sword blades suggest, more
cerulean than the sky itself, alternating with the original dark green
on the opposite sides of the waves, which last appeared but muddy in
comparison. It is a vitreous greenish blue, as I remember it, like those
patches of the winter sky seen through cloud vistas in the west before
sundown. Yet a single glass of its water held up to the light is as
colorless as an equal quantity of air. It is well-known that a large
plate of glass will have a green tint, owing, as the makers say, to its
"body," but a small piece of the same will be colorless. How large a
body of Walden water would be required to reflect a green tint I have
never proved. The water of our river is black or a very dark brown to
one looking directly down on it, and like that of most ponds, imparts to
the body of one bathing in it a yellowish tinge; but this water is of
such crystalline purity that the body of the bather appears of an
alabaster whiteness, still more unnatural, which, as the limbs are
magnified and distorted withal, produces a monstrous effect, making fit
studies for a Michael Angelo.

The water is so transparent that the bottom can easily be discerned at
the depth of twenty-five or thirty feet. Paddling over it, you may see
many feet beneath the surfa