between the great lakes of Canada and the country of the Miamis. At
the time of floods, the waters flowing into the lakes communicate with
those which run into the Mississippi; and it is practicable to proceed
by boats from the sources of the river St. Mary to the Wabash, as well
as from the Chicago to the Illinois. These analogous facts appear to
me well worthy of the attention of hydrographers.

The land that surrounds the lake of Valencia being entirely flat and
even, a diminution of a few inches in the level of the water exposes
to view a vast extent of ground covered with fertile mud and organic
remains.* (* This I observed daily in the Lake of Mexico.) In
proportion as the lake retires, cultivation advances towards the new
shore. These natural desiccations, so important to agriculture, have
been considerable during the last ten years, in which America has
suffered from great droughts. Instead of marking the sinuosities of
the present banks of the lake, I have advised the rich landholders in
these countries to fix columns of granite in the basin itself, in
order to observe from year to year the mean height of the waters. The
Marquis del Toro has undertaken to put this design into execution,
employing the fine granite of the Sierra de Mariara, and establishing
limnometers, on a bottom of gneiss rock, so common in the lake of
Valencia.

It is impossible to anticipate the limits, more or less narrow, to
which this basin of water will one day be confined, when an
equilibrium between the streams flowing in and the produce of
evaporation and filtration, shall be completely established. The idea
very generally spread, that the lake will soon entirely disappear,
seems to me chimerical. If in consequence of great earthquakes, or
other causes equally mysterious, ten very humid years should succeed