The Etymologies of Isidore of Seville - Pot-pourri

third has a half, thus: (fig.). The fourth is full, thus: (fig.).
The fifth is half again, [from the full side], thus: (fig.).
The sixth is a section again, thus (fig.). The seventh is
two-horned, thus: (fig.). 2.Theseventh lunar day, when
the moon is a half, and the twenty-second, when it is a
half, are the midpoints of its orbit (fig.), and the other
days are proportional.
lv. Interlunar intervals (De interluniis) The interlunar
interval of the moon is the time between the waning
and the waxing moon. This is the thirtieth day, when the
moon does not shine. At that time the moon cannot be
seen, because it is in conjunction with the sun and darkened.
But it is seen the moment it isrebornbymoving
gradually away from the sun.
lvi. The path of the moon (De cursu lunae) 1. The
moon measures out the span of a month in its alternations
of losing and receiving light. Therefore, it proceeds
on an oblique path, not a straight one like the sun,
indeed, lest it fall into the central plane of the earth and
frequently undergo eclipse. 2.For its circular path is close
to the earth. When it is waxing, its horns look to the east,
and when it is waning they look to the west, and justly
so, since it is about to set and lose its light.
lvii. The proximity of the moon to the earth (De vicinitate
lunae ad terras) The moon is nearer to the earth
than the sun is. Whence, due to its shorter orbit, it completes
its course more quickly, for the journey that the
sun completes in 365 days the moon runs through in
thirty days. Whence the ancients established months
based on the moon, and years based on the course of
the sun.
lviii. Eclipse of the sun (De eclipsi solis) An eclipse
of the sun occurs whenever the moon, on the thirtieth
lunar day, comes to that line where the sun travels, and
by interposing itself before the sun, conceals it. Thus to
us the sun appears to vanish when the orb of the moon
is set before it.
lix. Eclipse of the moon (De eclipsi lunae) 1.Aneclipse
of the moon occurs whenever the moon runs into the
32 Isidore himself is among those who do not observe these differentiae.
The Etymologies III.liv.2–lxv 103
shadow of the earth. The moon is thought not to have
its own light, but to be illuminated by the sun; hence it
disappears if the earth’s shadow comes between it and
the sun. 2. Thishappens to the moon on the fifteenth
lunar day, until it leaves the central part and the shadow
of the intervening earth and sees the sun, or is seen by
the sun.
lx. The differences between stars, star clusters, and
constellations (De differentia stellarum, siderum, et
astrorum) 1. Stars (stella), star clusters (sidus), and constellations
(astrum)aredifferentfromeachother.Thusa
star is any individual body, but star clusters are made up
of several stars, such as the Hyades and the Pleiades. 2.
Constellations are large patterns of stars, such as Orion
and Bootes. But writers confuse these terms, and use
astrum instead of stella,andstella instead of sidus. 32
lxi. The light of stars (De lumine stellarum) Stars are
said not to possess their own light, but to be illuminated
by the sun, as the moon is.
lxii. The location of the stars (De stellarum situ) Stars
are unmoving and, being fixed, are carried with the heavens
in perpetual motion. They do not set during the day,
but they are obscured by the brightness of the sun.
lxiii. Thecourseofthestars(Destellarumcursu) Stars
are either carried or move. The ones that are fixed in the
sky and turn with the sky are carried. But some [like]
planets, that is, ‘wanderers,’ move. However, they carry
out their roaming courses within a defined boundary.
lxiv. The changing course of the stars (De vario cursu
stellarum) Because they are carried across the various
orbits of the heavenly planets, some stars rise earlier and
set later, while others rise later and reach the point of
setting sooner. Some rise together but do not set at the
same time. But all return to their proper course in their
own time.
lxv. The distances between the stars (De stellarum
intervallis) The stars differ from each other in their distance
from the earth, and for this reason they appear
unequal to our eyes, being either brighter or less bright.
Thus many stars are larger than the ones that we see as