In such a day, in September or October, Walden is a perfect forest mirror, set round with stones as precious to my eye as if fewer or rarer. Nothing so fair, so pure, and at the same time so large, as a lake, perchance, lies on the surface of the earth. Sky water. It needs no fence. Nations come and go without defiling it. It is a mirror which no stone can crack, whose quicksilver will never wear off, whose gilding Nature continually repairs; no storms, no dust, can dim its surface ever fresh;Ma mirror in which all impurity presented to it sinks, swept and dusted by the sun's hazy brush,—this the light-dust cloth,—which retains no breath that is breathed on it, but sends its own to float as clouds high above its surface, and be reflected in its bosom still.