tenacious than that of the plains, and if the sheltering forest has been
destroyed, it is contined by few of the threads and ligaments by which
nature had bound it together, and attached it to the rocky groundwork.
Hence every considerable shower lays bare its roods of rock, and the
torrents sent down by the thaws of spring, and by occasional heavy
discharges of the summer and autumnal rains, are seas of mud and rolling
stones that sometimes lay waste and bury beneath them acres, and even
miles, of pasture and field and vineyard. [Footnote: The character of
geological formation is an element of very great importance in
determining the amount of erosion produced by running water, and, of
course, in measuring the consequences of clearing off the forests. The
soil of the French Alps yields very readily to the force of currents,
and the declivities of the northern Apennines, as well as of many minor
mountain ridges in Tuscany and other parts or Italy, are covered with
earth which becomes itself almost a fluid when saturated with water.
Hence the erosion of such surfaces is vastly greater than on many other
mountains of equal steepness of inclination. The traveller who passes
over the route between Bologna and Florence, and the Perugia and the
Siena roads from the latter city to Rome, will have many opportunities
of observing such localities.]


Destructiveness of Man.

Man has too long forgotten that the earth was given to him for usufruct
alone, not for consumption, still less for profligate waste. Nature has
provided against the absolute destruction of any of her elementary
matter, the raw material of her works; the thunderbolt and the tornado,
the most convulsive throes of even the volcano and the earthquake, being
only phenomena of decomposition and recomposition. But she has left it