t their oaths.
Every twenty-nine or thirty days we see a silver crescent in the
west, and are glad if it comes over the right shoulder--so [Page
152] much tribute does habit pay to superstition. The next night it
is thirteen degrees farther east from the sun. We note the stars it
occults, or passes by, and leaves behind as it broadens its disk,
till it rises full-orbed in the east when the sun sinks in the west.
It is easy to see that the moon goes around the earth from west to
east. Afterward it rises later and smaller each night, till at
length, lost from sight, it rises about the same time as the sun,
and soon becomes the welcome crescent new moon again.

The same peculiarities are always evident in the visible face of
the moon; hence we know that it always presents the same side to
the earth. Obviously it must make just one axial to one orbital
revolution. Hold any body before you at arm's-length, revolve it
one-quarter around you until exactly overhead. If it has not revolved
on an axis between the hands, another quarter of the surface is
visible; but if in going up it is turned a quarter over, by the
hands holding it steady, the same side is visible. Three causes
enable us to see a little more than half the moon's surface: 1. The
speed with which it traverses the ellipse of its orbit is variable.
It sometimes gets ahead of us, sometimes behind, and we see farther
around the front or back part. 2. The axis is a little inclined to
the plane of its orbit, and its orbit a little inclined to ours;
hence we see a little over its north pole, and then again over
the south pole. 3. The earth being larger, its inhabitants see
a little more than half-way around a smaller body. These causes
combined enable us to see 576/1000 of the moon's surface. Our eyes
will never see the other side of the moon. If, now, being solid,
her axial revolution could [Page 153] be increased enough to make
one more revolution in two or three years, that difference between
her axial and orbital revolution would give the future inhabitants
of the earth a view of the entire circumference of the moon. Yet if
the moon were once in a fluid state, or had oceans on the surface,
the enormous tide caused by the earth would produce friction enough,
as they moved over the surface, to gradually retard the axial
revolution till the two tidal elevations remained fixed toward and
opposite the earth, and then the axial and orbital revolutions would
correspond, a