elliptical orbits by the great law of gravitation, some few in
turn possess satellites. Uranus has eight, Saturn eight, Jupiter
four, Neptune possibly three, and the Earth one. This last, one
of the least important of the entire solar system, we call the
Moon; and it is she whom the daring genius of the Americans
professed their intention of conquering.

The moon, by her comparative proximity, and the constantly
varying appearances produced by her several phases, has always
occupied a considerable share of the attention of the
inhabitants of the earth.

From the time of Thales of Miletus, in the fifth century B.C.,
down to that of Copernicus in the fifteenth and Tycho Brahe in
the sixteenth century A.D., observations have been from time to
time carried on with more or less correctness, until in the
present day the altitudes of the lunar mountains have been
determined with exactitude. Galileo explained the phenomena of
the lunar light produced during certain of her phases by the
existence of mountains, to which he assigned a mean altitude of
27,000 feet. After him Hevelius, an astronomer of Dantzic,
reduced the highest elevations to 15,000 feet; but the
calculations of Riccioli brought them up again to 21,000 feet.

At the close of the eighteenth century Herschel, armed with a powerful
telescope, considerably reduced the preceding measurements.
He assigned a height of 11,400 feet to the maximum elevations,
and reduced the mean of the different altitudes to little more
than 2,400 feet. But Herschel's calculations were in their turn
corrected by the observations of Halley, Nasmyth, Bianchini,