Page:Excursions (1863) Thoreau.djvu/210

202 and physically, if, instead of sitting up so very late, he honestly slumbered a fool's allowance.

There may be an excess even of informing light. Niépce, a Frenchman, discovered "actinism," that power in the sun's rays which produces a chemical effect,—that granite rocks, and stone structures, and statues of metal, "are all alike destructively acted upon during the hours of sunshine, and, but for provisions of Nature no less wonderful, would soon perish under the delicate touch of the most subtile of the agencies of the universe," But he observed that "those bodies which underwent this change during the daylight possessed the power of restoring themselves to their original conditions during the hours of night, when this excitement was no longer influencing them." Hence it has been inferred that "the hours of darkness are as necessary to the inorganic creation as we know night and sleep are to the organic kingdom." Not even does the moon shine every night, but gives place to darkness.

I would not have every man nor every part of a man cultivated, any more than I would have every acre of earth cultivated: part will be tillage, but the greater part will be meadow and forest, not only serving an immediate use, but preparing a mould against a distant future, by the annual decay of the vegetation which it supports.