The Ten Books on Architecture
shortest. Consequently, this season, from the shortness of the day, is
called bruma or dies brumales. Crossing from Capricornus into Aquarius,
he causes the days to increase to the length which they had when he was
in Sagittarius. From Aquarius he enters Pisces at the time when Favonius
begins to blow, and here his course is the same as in Scorpio. In this
way the sun passes round through the signs, lengthening or shortening
the days and hours at definite seasons.
I shall next speak of the other constellations formed by arrangements of
stars, and lying to the right and left of the belt of the signs, in the
southern and northern portions of the firmament.
CHAPTER IV
THE NORTHERN CONSTELLATIONS
1. The Great Bear, called in Greek [Greek: arktos] or [Greek: helikê],
has her Warden behind her. Near him is the Virgin, on whose right
shoulder rests a very bright star which we call Harbinger of the
Vintage, and the Greeks [Greek: protrygêtês]. But Spica in that
constellation is brighter. Opposite there is another star, coloured,
between the knees of the Bear Warden, dedicated there under the name of
Arcturus.
2. Opposite the head of the Bear, at an angle with the feet of the
Twins, is the Charioteer, standing on the tip of the horn of the Bull;
hence, one and the same star is found in the tip of the left horn of the
Bull and in the right foot of the Charioteer. Supported on the hand of
the Charioteer are the Kids, with the She-Goat at his left shoulder.
Above the Bull and the Ram is Perseus, having at his right...[11] with
the Pleiades moving beneath, and at his left the head of the Ram. His
right hand rests on the likeness of Cassiopea, and with his left he
holds the Gorgon's head by its top over the Ram, laying it at the feet
of Andromeda.
[Note 11: From this point to the end of section 3 the text is often
hopelessly corrupt. The translation follows, approximately, the
manuscript reading, but cannot pretend to be exact.]
3. Above Andromeda are the Fishes, one above her belly and the other
above the backbone of the Horse. A very bright star terminates both the
belly of the Horse and the head of Andromeda. Andromeda's right hand
rests above the likeness of Cassiopea, and her left above the Northern
Fish. The Waterman's head is above that of the Horse. The Horse's hoofs
lie close to the Waterman's knees. Cassiopea is set apart in the midst.
High above the He-Goat are the Eagle and the Dolphin, and near them is
the Arrow. Farther on is the Bird, whose right wing grazes the head and
sceptre of Cepheus, with its left resting over Cassiopea. Under the tail
of the Bird lie the feet of the Horse.
4. Above the Archer, Scorpion, and Balance, is the Serpent, reaching to
the Crown with the end of its snout. Next, the Serpent-holder grasps the
Serpent about the middle in his hands, and with his left foot treads
squarely on the foreparts of the Scorpion. A little way from the head of
the Serpent-holder is the head of the so-called Kneeler. Their heads are
the more readily to be distinguished as the stars which compose them are
by no means dim.
5. The foot of the Kneeler rests on the temple of that Serpent which is
entwined between the She-Bears (called Septentriones). The little
Dolphin moves in front of the Horse. Opposite the bill of the Bird is
the Lyre. The Crown is arranged between the shoulders of the Warden and
the Kneeler. In the northern circle are the two She-Bears with their
shoulder-blades confronting and their breasts turned away from one
another. The Greeks call the Lesser Bear [Greek: kynosoura], and the
Greater [Greek: elikê]. Their heads face different ways, and their tails
are shaped so that each is in front of the head of the other Bear; for
the tails of both stick up over them.
6. The Serpent is said to lie stretched out between their tails, and in
it there is a star, called Polus, shining near the head of the Greater
Bear. At the nearest point, the Serpent winds its head round, but is
also flung in a fold round the head of the Lesser Bear, and stretches
out close to her feet. Here it twists back, making another fold, and,
lifting itself up, bends its snout and right temple from the head of the
Lesser Bear round towards the Greater. Above the tail of the Lesser Bear
are the feet of Cepheus, and at this point, at the very top, are stars
forming an equilateral triangle. There are a good many stars common to
the Lesser Bear and to Cepheus.
I have now mentioned the constellations which are arranged in the heaven
to the right of the east, between the belt of the signs and the north. I
shall next describe those that Nature has distributed to the left of the
east and in the southern regions.
CHAPTER V
THE SOUTHERN CONSTELLATIONS
1. First, under the He-Goat lies the Southern Fish, facing towards the
tail of the Whale. The Censer is under the Scorpion's sting. The fore
parts of the Centaur are next to the Balance and the Scorpion, and he
holds in his hands the figure which astronomers call the Beast. Beneath
the Virgin, Lion, and Crab is the twisted girdle formed by the Snake,
extending over a whole line of stars, his snout raised near the Crab,
supporting the Bowl with the middle of his body near the Lion, and
bringing his tail, on which is the Raven, under and near the hand of the
Virgin. The region above his shoulders is equally bright.
2. Beneath the Snake's belly, at the tail, lies the Centaur. Near the
Bowl and the Lion is the ship named Argo. Her bow is invisible, but her
mast and the parts about the helm are in plain sight, the stern of the
vessel joining the Dog at the tip of his tail. The Little Dog follows
the Twins, and is opposite the Snake's head. The Greater Dog follows the
Lesser. Orion lies aslant, under the Bull's hoof; in his left hand
grasping his club, and raising the other toward the Twins.
3. At his feet is the Dog, following a little behind the Hare. The Whale
lies under the Ram and the Fishes, and from his mane there is a slight
sprinkling of stars, called in Greek [Greek: harpedonai], regularly
disposed towards each of the Fishes. This ligature by which they hang is
carried a great way inwards, but reaches out to the top of the mane of
the Whale. The River, formed of stars, flows from a source at the left
foot of Orion. But the Water, said to pour from the Waterman, flows
between the head of the Southern Fish and the tail of the Whale.
4. These constellations, whose outlines and shapes in the heavens were
designed by Nature and the divine intelligence, I have described
according to the view of the natural philosopher Democritus, but only
those whose risings and settings we can observe and see with our own
eyes. Just as the Bears turn round the pivot of the axis without ever
setting or sinking under the earth, there are likewise stars that keep
turning round the southern pivot, which on account of the inclination of
the firmament lies always under the earth, and, being hidden there, they
never rise and emerge above the earth. Consequently, the figures which
they form are unknown to us on account of the interposition of the
earth. The star Canopus proves this. It is unknown to our vicinity; but
we have reports of it from merchants who have been to the most distant
part of Egypt, and to regions bordering on the uttermost boundaries of
the earth.
CHAPTER VI
ASTROLOGY AND WEATHER PROGNOSTICS
1. I have shown how the firmament, and the twelve signs with the
constellations arranged to the north and south of them, fly round the
earth, so that the matter may be clearly understood. For it is from this
revolution of the firmament, from the course of the sun through the
signs in the opposite direction, and from the shadows cast by
equinoctial gnomons, that we find the figure of the analemma.
2. As for the branch of astronomy which concerns the influences of the
twelve signs, the five stars, the sun, and the moon upon human life, we
must leave all this to the calculations of the Chaldeans, to whom
belongs the art of casting nativities, which enables them to declare the
past and the future by means of calculations based on the stars. These
discoveries have been transmitted by the men of genius and great
acuteness who sprang directly from the nation of the Chaldeans; first of
all, by Berosus, who settled in the island state of Cos, and there
opened a school. Afterwards Antipater pursued the subject; then there
was Archinapolus, who also left rules for casting nativities, based not
on the moment of birth but on that of conception.
3. When we come to natural philosophy, however, Thales of Miletus,
Anaxagoras of Clazomenae, Pythagoras of Samos, Xenophanes of Colophon,
and Democritus of Abdera have in various ways investigated and left us
the laws and the working of the laws by which nature governs it. In the
track of their discoveries, Eudoxus, Euctemon, Callippus, Meto,
Philippus, Hipparchus, Aratus, and others discovered the risings and
settings of the constellations, as well as weather prognostications from
astronomy through the study of the calendars, and this study they set
forth and left to posterity. Their learning deserves the admiration of
mankind; for they were so solicitous as even to be able to predict, long
beforehand, with divining mind, the signs of the weather which was to
follow in the future. On this subject, therefore, reference must be made
to their labours and investigations.
CHAPTER VII
THE ANALEMMA AND ITS APPLICATIONS
1. In distinction from the subjects first mentioned, we must ourselves
explain the principles which govern the shortening and lengthening of
the day. When the sun is at the equinoxes, that is, passing through
Aries or Libra, he makes the gnomon cast a shadow equal to eight ninths
of its own length, in the latitude of Rome. In Athens, the shadow is
equal to three fourths of the length of the gnomon; at Rhodes to five
sevenths; at Tarentum, to nine elevenths; at Alexandria, to three
fifths; and so at other places it is found that the shadows of
equinoctial gnomons are naturally different from one another.
2. Hence, wherever a sundial is to be constructed, we must take the
equinoctial shadow of the place. If it is found to be, as in Rome, equal
to eight ninths of the gnomon, let a line be drawn on a plane surface,
and in the middle thereof erect a perpendicular, plumb to the line,
which perpendicular is called the gnomon. Then, from the line in the
plane, let the line of the gnomon be divided off by the compasses into
nine parts, and take the point designating the ninth part as a centre,
to be marked by the letter A. Then, opening the compasses from that
centre to the line in the plane at the point B, describe a circle. This
circle is called the meridian.
3. Then, of the nine parts between the plane and the centre on the
gnomon, take eight, and mark them off on the line in the plane to the
point C. This will be the equinoctial shadow of the gnomon. From that
point, marked by C, let a line be drawn through the centre at the point
A, and this will represent a ray of the sun at the equinox. Then,
extending the compasses from the centre to the line in the plane, mark
off the equidistant points E on the left and I on the right, on the two
sides of the circumference, and let a line be drawn through the centre,
dividing the circle into two equal semicircles. This line is called by
mathematicians the horizon.
4. Then, take a fifteenth part of the entire circumference, and, placing
the centre of the compasses on the circumference at the point where the
equinoctial ray cuts it at the letter F, mark off the points G and H on
the right and left. Then lines must be drawn from these (and the centre)
to the line of the plane at the points T and R, and thus, one will