e water will keep it in
motion, even if there were no declivity at all. Many great rivers,
in fact, flow with an almost interruptible declivity. Rivers which
descend from primitive mountains into secondary lands, often form
_cascades and cataracts_. Such are the cataracts of the Nile,
of the Ganges, and some other great rivers, which, according to
Desmarest, evidently mark the limits of the ancient land.
Cataracts are also formed by lakes: of this description are the
celebrated Falls of the Niagara; but the most picturesque falls
are those of rapid rivers, bordered by trees and precipitous
rocks. Sometimes we see a body of water, which, before it arrives
at the bottom, is broken and dissipated into showers, like the
Staubbach, (see _Mirror,_ vol. xiv. p. 385.); sometimes it forms
a watery arch, projected from a rampart of rock, under which the
traveller may pass dryshod, as the "falling spring" of Virginia;
in one place, in a granite district, we see the Trolhetta, and the
Rhine not far from its source, urge on their foaming billows
among the pointed rocks; in another, amidst lands of a calcareous
formation, we see the Czettina and the Kerka, rolling down
from terrace to terrace, and presenting sometimes a sheet, and
sometimes a wall, of water. Some magnificent cascades have been
formed, at least in part, by the hands of man: the cascades of
Velino, near Terni, have been attributed to Pope Clement VIII.;
other cataracts, like those of Tunguska, in Siberia, have
gradually lost their elevation by the wearing away of the rocks,
and have now only a rapid descent."--_Maltebrun_, vol. i.

The Engraving includes the falls of the river, with the village
of Rochester, seven miles south of Lake Ontario. This place, for
population, extent, and trade, will soon rank among the American
cities: it was not settled until about the close of the last war;
its progress was slow until the year 1820, from which period it has
rapidly improved. In 1830 it contained upwards of 12,000 inhabitants:
the first census of the village was taken in December, 1815, when the
number of inhabitants was three hundred and thirty-one. The aqueduct
which takes the Erie canal across the river forms a prominent object
of interest to all travellers. It is of hewn sto