THE TERRESTRIAL WORLD OF THE ANCIENTS.--COSMOGRAPHY AND GEOGRAPHY.
With respect to the shape and position of the earth itself in the
material universe, and the question of its motion or immobility, we
cannot go so far back as in the case of the heavens, since it obviously
requires more observation, and is not so pressing for an answer.
Amongst the Greeks several authors appear to have undertaken the
subject, but only one complete work has come down to us which undertakes
it directly. This is a work attributed to Aristotle, _De Mundo_. It is
addressed to Alexander, and by some is considered to be spurious,
because it lacks the majestic obscurity that in his acknowledged works
repels the reader. Although, however, it is not as obscure as it might
be, for the writer, it is quite bad enough, and its dryness and
vagueness, its mixture of metaphysical and physical reasoning, logic and
observation, and the change that has naturally passed over the meanings
of many common words since they were written, render it very tedious
and unpleasant reading.
Nevertheless, as presenting us with the first recorded ideas on these
questions of the nature and properties of the earth, it deserves
attentive study. It is not a system of observations like those of
Ptolemy and the Alexandrian School, but an entirely theoretical work. It
is founded entirely on logic; but unfortunately, if the premisses are
bad, the better the syllogism the more erroneous will be the conclusion;
and it is just this which we find here. Thus if he be asked whether the
earth turns or the heavens, he will reply that the earth is _evidently_
in repose, and that this is the case not only because we observe it to
be so, but because it is a necessity that it should be; because repose
is _natural_ to the earth, and it is _naturally_ in equilibrium. This
idea of "natural" leads very often astray. He is guided to his idea of
what is natural by seeing what is, and then argues that what is, or
appears to be, must be, because it is natural--thus arguing in a circle.
Another example may be given in his answer to the question, Why must the
stars move round the earth? He says it is natural, because a circle is a
more perfect line, and must therefore be described by the perfect stars,
and a circle is perfect because it has no ends! Unfortunately there are
other curves that have no ends; but the circle was considered, without
more reason, the most perfect curve, and therefore the planets must move
in circles--an idea which had to wait till Kepler's time to be
exploded. One more specimen of this style may be quoted, namely, his
proof that every part of heaven must be eternally moving, while the
earth must be in the centre and at rest. The proof is this. Everything
which performs any act has been made for the purpose of that act. Now
the work of God is immortality, from which it follows that all that is
divine must have an eternal motion. But the heavens have a divine
quality, and for this reason they have a spherical shape and move
eternally in a circle. Now when a body has a circular motion, one part
of it must remain at rest in its place, namely, that which is in the
centre; the earth is in the centre--therefore it is at rest.
Aristotle says in this work that there are two kinds of simple motion,
that in a circle and that in a straight line. The latter belongs to the
elements, which either go up or down, and the former to the celestial
bodies, whose nature is more divine, and which have never been known to
change; and the earth and world must be the only bodies in existence,
for if there were another, it must be the contrary to this, and there is
no contrary to a circle; and again, if there were any other body, the
earth would be attracted towards it, and move, which it does not. Such
is the style of argument which was in those days thought conclusive, and
which with a little development and inflation of language appeared
intensely profound.
But what brings these speculations to the subject we have now in hand
is this: that when Aristotle thus proves the earth to be immovable in
the centre of the universe, he is led on to inquire how it is possible
for it to remain in one fixed place. He observed that even a small
fragment of earth, when it is raised into the air and then let go,
immediately falls without ever stopping in one place--falling, as he
supposed, all the quicker according to its weight; and he was therefore
puzzled to know why the whole mass of the earth, notwithstanding its
weight, could be kept from falling.
Aristotle examines one by one the answers that have been given to this
question. Thus Xenophanes gave to the earth infinitely extended roots,
against which Empedocles uses such arguments as we should use now.
Thales of Miletus makes the earth rest upon water, without finding
anything on which the water itself can rest, or answering the question
how it is that the heavier earth can be supported on the lighter water.
Anaxemenes, Anaxagoras, and Democritus, who make the earth flat,
consider it to be sustained by the air, which is accumulated below it,
and also presses down upon it like a great coverlet. Aristotle himself
says that he agrees with those philosophers who think that the earth is
brought to the centre by the primitive rotation of things, and that we
may compare it, as Empedocles does, to the water in glasses which are
made to turn rapidly, and which does not fall out or move, even though
upside down. He also quotes with approval another opinion somewhat
similar to this, namely, that of Anaximander, which states that the
earth is in repose, on account of its own equilibrium. Placed in the
centre and at an equal distance from its extremities, there is no reason
why it should move in one direction rather than the other, and rests
immovable in the centre without being able to leave it.
The result of all is that Aristotle concludes that the earth is
immovable, in the centre of the universe, and that it is not a star
circulating in space like other stars, and that it does not rotate upon
its axis; and he completes the system by stating that the earth is
spherical, which is proved by the different aspects of the heavens to a
voyager to the north or to the south.
Such was the Aristotelian system, containing far more error than truth,
which was the first of any completeness. Scattered ideas, however, on
the shape and method of support of the earth and the cause of various
phenomena, such as the circulation of the stars, are met with besides in
abundance.
The original ideas of the earth were naturally tinged by the
prepossessions of each race, every one thinking his own country to be
situated in the centre. Thus among the Hindoos, who lived near the
equator, and among the Scandinavians, inhabiting regions nearer the
pole, the same meaning attaches to the words by which they express their
own country, _medpiama_ and _medgard_, both meaning the central
habitation. Olympus among the Greeks was made the centre of the earth,
and afterwards the temple of Delphi. For the Egyptians the central point
was Thebes; for the Assyrians it was Babylon; for the Indians it was the
mountain Mero; for the Hebrews Jerusalem. The Chinese always called
their country the central empire. It was then the custom to denote the
world by a large disc, surrounded on all sides by a marvellous and
inaccessible ocean. At the extremities of the earth were placed
imaginary regions and fortunate isles, inhabited by giants or pigmies.
The vault of the sky was supposed to be supported by enormous mountains
and mysterious columns.
Numerous variations have been suggested on the earliest supposed form of
the earth, which was, as we have seen in a former chapter, originally
supposed to be an immense flat of infinite depth, and giving support to
the heavens.
As travels extended and geography began to be a science, it was remarked
that an immense area of water circumscribed the solid earth by irregular
boundaries--whence the idea of a universal ocean.
When, however, it was perceived that the horizon at sea was always
circular, it was supposed that the ocean was bounded, and the whole
earth came to be represented as contained in a circle, beneath which
were roots reaching downwards without end, but with no imagined
support.
[Illustration: FIG. 25.--THE EARTH FLOATING.]
[Illustration: FIG. 26.--THE EARTH WITH ROOTS.]
The Vedic priests asserted that the earth was supported on twelve
columns, which they very ingeniously turned to their own account by
asserting that these columns were supported by virtue of the sacrifices
that were made to the gods, so that if these were not made the earth
would collapse.
[Illustration: FIG. 27.--THE EARTH OF THE VEDIC PRIESTS.]
These pillars were invented in order to account for the passing of the
sun beneath the earth after his setting, for which at first they were
obliged to imagine a system of tunnels, which gradually became enlarged
to the intervals between the pillars.
The Hindoos made the hemispherical earth to be supported upon four
elephants, and the four elephants to stand on the back of an immense
tortoise, which itself floated on the surface of a universal ocean. We
are not however to laugh at this as intended to be literal; the
elephants symbolised, it may be, the four elements, or the four
directions of the compass, and the tortoise was the symbol for strength
and for eternity, which was also sometimes represented by a serpent.
[Illustration: FIG. 28.--HINDOO EARTH.]
The floating of the earth on water or some other liquid long held
ground. It was adopted by Thales, and six centuries later Seneca adopts
the same opinion, saying that the humid element that supports the
earth's disc like a vessel may be either the ocean or some liquid more
simple than water.
Diodorus tells us that the Chaldeans considered the earth hollow and
boat-shaped--perhaps turned upside down--and this doctrine was
introduced into Greece by Heraclitus of Ephesus.
[Illustration: FIG. 29.--THE EARTH OF ANAXIMANDER.]
Anaximander represents the earth as a cylinder, the upper face of which
alone is inhabited. This cylinder, he states, is one-third as high as
its diameter, and it floats freely in the centre of the celestial vault,
because there is no reason why it should move to one side rather than
the other. Leucippus, Democritus, Heraclitus, and Anaxagoras all adopted
this purely imaginary form. Europe made the northern half, and Lybia
(Africa) and Asia the southern, while Delphi was in the centre.
Anaximenes, without giving a precise opinion as to the form of the
earth, made it out to be supported on compressed air, though he gave no
idea as to how the air was to be compressed.
Plato thought to improve upon these ideas by making the earth cubical.
The cube, which is bound by six equal faces, appeared to him the most
perfect of solids, and therefore most suitable for the earth, which was
to stand in the centre of the universe.
[Illustration: FIG. 30.--PLATO'S CUBICAL EARTH.]
Eudoxus, who in his long voyages throughout Greece and Egypt had seen
new constellations appear as he went south, while others to the north
disappeared, deduced the sphericity of the earth, in which opinion he
was followed by Archimedes, and, as we have seen, by Aristotle.
According to Achilles Tatius, Xenophanes gave to the earth the shape of
an immense inclined plane, which stretched out to infinity. He drew it
in the form of a vast mountain. The summit only was inhabited by men,
and round it circulated the stars, and the base was at an infinite
depth. Hesiod had before this obscurely said: "The abyss is surrounded
by a brazen barrier; above it rest the roots of the earth." Epicurus and
his school were well pleased with this representation. If such were the
foundations of the earth, then it was impossible that the sun, and moon,
and stars should complete their revolutions beneath it. A solid and
indefinite support being once admitted, the Epicurean ideas about the
stars were a necessary consequence; the stars must inevitably be put out
each day in the west, since they are not seen to return to the place
whence they started, and they must be rekindled some hours afterwards in
the east. In the days of Augustus, Cleomedes still finds himself obliged
to combat these Epicurean ideas about the setting and rising of the sun
and stars. "These stupid ideas," he says, "have no other foundation than
an old woman's story--that the Iberians hear each night the hissing
noise made by the burning sun as it is extinguished, like a hot iron in
the waters of the ocean." Modern travellers have shown us that similar
ideas about the support of the earth have been entertained by more
remote people. Thus, in the opinion of the Greenlanders, handed down
from antiquity to our own days, the earth is supported on pillars, which
are so consumed by time that they often crack, and were it not that they
are supported by the incantations of the magicians, they would long
since have broken down. This idea of the breaking of the pillars may
possibly have originated in the known sinking of the land beneath the
sea, which is still going on even at the present day.
[Illustration: FIG. 31.--EGYPTIAN REPRESENTATION OF THE EARTH.]
An ancient Egyptian papyrus in the library of Paris gives a very curious
hieroglyphical representation of the universe. The earth is here figured
under the form of a reclining figure, and is covered with leaves. The
heavens are personified by a goddess, which forms the vault by her
star-bespangled body, which is elongated in a very peculiar manner. Two
boats, carrying, one the rising sun, and the other the setting sun, are
represented as moving along the heavens over the body of the goddess. In
the centre of the picture is the god, Maon, a divine intelligence, which
presides over the equilibrium of the universe.
We will now pass on from the early ideas of the general shape and
situation of the world to inquire into the first outlines of
geographical knowledge of details.
Of all the ancient writings which deal with such questions, the Hebrew
Scriptures have the greatest antiquity, and in them are laid down many
details of known countries, from which a fair map of the world as known
to them might be made out. The prophet Esdras believed that six-sevenths
of the earth was dry land--an idea which could not well be exploded till
the great oceans had been traversed and America discovered.
More interesting, as being more complete, and written to a certain
extent for the very purpose of relating what was known of the geography
of the earth, are the writings of the oldest Grecian poets. The first
elements of Grecian geography are contained in the two national and
almost sacred poems, the _Iliad_ and _Odyssey_. So important have these
writings been considered in regard to ancient geography, that for many
centuries discussions have been carried on with regard to the details,
though evidently fictitious, of the voyage of Ulysses, and twenty lines
of the _Iliad_ have furnished matter for a book of thirty volumes.
The shield of Achilles, forged by Vulcan and described in the eighteenth
book of the _Iliad_, gives us an authentic representation of the
primitive cosmographical ideas of the age. The earth is there figured as
a disc, surrounded on all sides by the _River Ocean_. However strange it
may appear to us, to apply the term _river_ to the ocean, it occurs too
often in Homer and the other ancient poets to admit of a doubt of its
being literally understood by them. Hesiod even describes the sources of
the ocean at the western extremity of the world, and the representation
of these sources was preserved from age to age amongst authors posterior
to Homer by nearly a thousand years. Herodotus says plainly that the
geographers of his time drew their maps of the world according to the
same ideas; the earth was figured with them as a round disc, and the
ocean as a river, which washed it on all sides.
The earth's disc, the _orbis terrarum_, was covered according to Homer
by a solid vault or firmament, beneath which the stars of the day and
night were carried by chariots supported by the clouds. In the morning
the sun rose from the eastern ocean, and in the evening it declined into
the western; and a vessel of gold, the mysterious work of Vulcan,
carried it quickly back by the north, to the east again. Beneath the
earth Homer places, not the habitation of the dead, the caverns of
Hades, but a vault called Tartarus, corresponding to the firmament. Here
lived the Titans, the enemies of the gods, and no breath of wind, no
ray of light, ever penetrated to this subterranean world. Writers
subsequent to Homer by a century determined even the height of the
firmament and the depth of Tartarus. An anvil, they said, would take
nine days to fall from heaven to earth, and as many more to fall from
earth to the bottom of Tartarus. This estimate of the height of heaven
was of course far too small. If a body were to fall for nine days and
nights, or 777,600 seconds under the attraction of the earth, it would
only pass over 430,500 miles, that is not much more than half as far
again as the moon. A ray of light would only take two seconds to pass
over that distance, whereas it takes eight minutes to reach us from the
sun, and four hours to come from Neptune--to say nothing of the distance
of the stars.
The limits of the world in the Homeric cosmography were surrounded by
obscurity. The columns of which Atlas was the guardian were supported on
unknown foundations, and disappeared in the systems subsequent to Homer.
Beyond the mysterious boundary where the earth ended and the heavens
began an indefinite chaos spread out--a confused medley of life and
inanity, a gulf where all the elements of heaven, Tartarus, and earth
and sea are mixed together, a gulf of which the gods themselves are
afraid.
Ideas such as these prevailed long after geometers and astronomers had
proved the spherical form of the globe, and they were revived by the
early Christian geographers and have left their trace even on the
common language of to-day.
[Illustration: FIG. 32.--HOMERIC COSMOGRAPHY.]
The centre of the terrestrial disc was occupied by the continent and
isles of Greece, which in the time of Homer possessed no general name.
The centre of Greece passed therefore for the centre of the whole world;
and in Homer's system it was reckoned to be Olympus in Thessaly, but the
priests of the celebrated Temple of Apollo at Delphi (known then under
the name of Python) gave out a tradition that that sacred place was the
real centre of the habitable world.
The straits which separate Italy from Sicily were so to speak the
vestibule of the fabulous world of Homer. The threefold ebb and flow,
the howling of the monster Scylla, the whirlpools of Charybdis, the
floating rocks--all tell us that we are quitting here the region of
truth. Sicily itself, although already known under the name of
_Trinacria_, was filled with marvels; here the flocks of the Sun
wandered in a charming solitude under the guardianship of nymphs; here
the Cyclops, with one eye only, and the anthropophagous Lestrigons
scared away the traveller from a land that was otherwise fertile in corn
and wine. Two historical races were placed by Homer in Sicily, namely
the _Sicani_, and the _Siceli_, or _Siculi_.
To the west of Sicily we find ourselves in the midst of a region of
fables. The enchanted islands of Circe and Calypso, and the floating
island of Eolus can no longer be found, unless we imagine them to have
originated, like Graham's Island in this century, from volcanic
eruptions or elevations, and to have disappeared again by the action of
the sea.
The Homeric map of the world terminated towards the west by two fabulous
countries which have given rise to many traditions among the ancients,
and to many discussions among moderns. Near to the entrance of the
ocean, and not far from the sombre caverns where the dead are
congregated, Ulysses found the _Cimmerians_, "an unhappy people, who,
constantly surrounded by thick shadows, never enjoyed the rays of the
sun, neither when it mounted the skies, nor when it descended below the
earth." Still farther away, and in the ocean itself, and therefore
beyond the limits of the earth, beyond the region of winds and seasons,
the poet paints for us a Fortunate Land, which he calls _Elysium_, a
country where tempests and winter are unknown, where a soft zephyr
always blows, and where the elect of Jupiter, snatched from the common
lot of mortals, enjoy a perpetual felicity.
Whether these fictions had an allegory for their basis, or were founded
on the mistaken notions of voyagers--whether they arose in Greece, or,
as the Hebrew etymology of the name Cimmerian might seem to indicate, in
the east, or in Phenicia, it is certain that the images they present,
transferred to the world of reality, and applied successively to various
lands, and confused by contradictory explanations, have singularly
embarrassed the progress of geography through many centuries. The Roman
travellers thought they recognised the Fortunate Isles in a group to the
west of Africa, now known as the Canaries. The philosophical fictions of
Plato and Theopompus about Atlantes and Meropis have been long
perpetuated in historical theories; though of course it is possible that
in the numerous changes that have taken place in the surface of the
earth, some ancient vast and populous island may have descended beneath
the level of the sea. On the other side, the poetic imagination created
the _Hyperboreans_, beyond the regions where the northern winds were
generated, and according to a singular kind of meteorology, they
believed them for that reason to be protected from the cold winds.
Herodotus regrets that he has not been able to discover the least trace
of them; he took the trouble to ask for information about them from
their neighbours, the _Arimaspes_, a very clear-sighted race, though
having but a single eye; but they could not inform him where the
Hyperboreans dwelt. The Enchanted Isles, where the Hesperides used to
guard the golden fruit, and which the whole of antiquity placed in the
west, not far from the Fortunate Isles, are sometimes called Hyperborean
by authors well versed in the ancient traditions. It is also in this
sense that Sophocles speaks of the Garden of Phoebus, near the vault
of heaven, and not far from the _sources of the night_, _i.e._ of the
setting of the sun.
Avienus explains the mild temperature of the Hyperborean country by the
temporary proximity of the sun, since, according to the Homeric ideas,
it passes during the night by the northern ocean to return to its palace
in the east. This ancient tradition was not entirely exploded in the
time of Tacitus, who states that on the confines of Germany might be
seen the veritable setting of Apollo beyond the water, and he believes
that as in the east the sun gives rise to incense and balm by its great
proximity to the earth, so in the regions where it sets it makes the
most precious of juices to transude from the earth and form amber. It is
this idea that is embedded in the fables of amber being the tears of
gold that Apollo shed when he went to the Hyperborean land to mourn the
loss of his son AEsculapius, or by the sisters of Phaeton, changed into
poplars; and it is denoted by the Greek name for amber, _electron_--a
sun-stone. The Grecian sages, long before the time of Tacitus, said that
this very precious material was an exhalation from the earth that was
produced and hardened by the rays of the sun, which they thought came
nearer to the earth in the west and in the north.
Florus, in relating the expedition of Decimus Brutus along the coast of
Spain, gives great effect to the Epicurean views about the sun, by
declaring that Brutus only stopped his conquests after having witnessed
the actual descent of the sun into the ocean, and having heard with
horror the terrible noise occasioned by its extinction. The ancients
also believed that the sun and the other heavenly bodies were nourished
by the waters--partly the fresh water of the rivers, and partly the salt
water of the sea. Cleanthes gave the reason for the sun returning
towards the equator on reaching the solstices, that it could not go too
far away from the source of its nourishment. Pytheas relates that in the
Island of Thule, six days' journey north of Great Britain, and in all
that neighbourhood, there was no land nor sea nor air, but a compound of
all three, on which the earth and the sea were suspended, and which
served to unite together all the parts of the universe, though it was
not possible to go into these places, neither on foot nor in ships.
Perhaps the ice floating in the frozen seas and the hazy northern
atmosphere had been seen by some navigator, and thus gave rise to this
idea. As it stands, the history may be perhaps matched by that of the
amusing monk who said he had been to the end of the world and had to
stoop down, as there was not room to stand between heaven and earth at
their junction.
Homer lived in the tenth century before our era. Herodotus, who lived in
the fifth, developed the Homeric chart to three times its size. He
remarks at the commencement of his book that for several centuries the
world has been divided into three parts--Europe, Asia, and Libya; the
names given to them being female. The exterior limits of these countries
remained in obscurity notwithstanding that those boundaries of them that
lay nearest to Greece were clearly defined.
One of the greatest writers on ancient geography was Strabo, whose ideas
we will now give an account of. He seems to have been a disciple of
Hipparchus in astronomy, though he criticises and contradicts him
several times in his geography. He had a just idea of the sphericity of
the earth; but considered it as the centre of the universe, and
immovable. He takes pains to prove that there is only one inhabited
earth--not in this refuting the notion that the moon and stars might
have inhabitants, for these he considered to be insignificant meteors
nourished by the exhalations of the ocean; but he fought against the
fact of there being on this globe any other inhabited part than that
known to the ancients.
It is remarkable to notice that the proofs then used by geographers of
the sphericity of the earth are just those which we should use now. Thus
Strabo says, "The indirect proof is drawn from the centripetal force in
general, and the tendency that all bodies have in particular towards a
centre of gravity. The direct proof results from the phenomena observed
on the sea and in the sky. It is evident, for example, that it is the
curvature of the earth that alone prevents the sailor from seeing at a
distance the lights that are placed at the ordinary height of the eye,
and which must be placed a little higher to become visible even at a
greater distance; in the same way, if the eye is a little raised it will
see things which previously were hidden." Homer had already made the
same remark.
On this globe, representing the world, Strabo and the cosmographers of
his time placed the habitable world in a surface which he describes in
the following way: "Suppose a great circle, perpendicular to the
equator, and passing through the poles to be described about the sphere.
It is plain that the surface will be divided by this circle, and by the
equator into four equal parts. The northern and southern hemispheres
contain, each of them, two of these parts. Now on any one of these
quarters of the sphere let us trace a quadrilateral which shall have for
its southern boundary the half of the equator, for northern boundary a
circle marking the commencement of polar cold, and for the other sides
two equal and opposite segments of the circle that passes through the
poles. It is on one such quadrilateral that the habitable world is
placed." He figures it as an island, because it is surrounded on all
sides by the sea. It is plain that Strabo had a good idea of the nature
of gravity, because he does not distinguish in any way an upper or a
lower hemisphere, and declares that the quadrilateral on which the
habitable world is situated may be any one of the four formed in this
way.
The form of the habitable world is that of a "chlamys," or cloak. This
follows, he says, both from geometry and the great spread of the sea,
which, enveloping the land, covers it both to the east and to the west
and reduces it to a shortened and truncated form of such a figure that
its greatest breadth preserved has only a third of its length. As to the
actual length and breadth, he says, "it measures seventy thousand stadia
in length, and is bounded by a sea whose immensity and solitude renders
it impassable; while the breadth is less than thirty thousand stadia,
and has for boundaries the double region where the excess of heat on
one side and the excess of cold on the other render it uninhabitable."
The habitable world was thus much longer from east to west than it was
broad from north to south; from whence come our terms _longitude_, whose
degrees are counted in the former direction, and _latitude_, reckoned in
the latter direction.
Eratosthenes, and after him Hipparchus, while he gives larger numbers
than the preceding for the dimensions of the inhabited part of the
earth, namely, thirty-eight thousand stadia of breadth and eighty
thousand of length, declares that physical laws accord with calculations
to prove that the length of the habitable earth must be taken from the
rising to the setting of the sun. This length extends from the extremity
of India to that of Iberia, and the breadth from the parallel of
Ethiopia to that of Ierne.
That the earth is an island, Strabo considers to be proved by the
testimony of our senses. For wherever men have reached to the
extremities of the earth they have found the sea, and for regions where
this has not been verified it is established by reasoning. Those who
have retraced their steps have not done so because their passage was
barred by any continent, but because their supplies have run short, and
they were afraid of the solitude; the water always ran freely in front
of them.
It is extraordinary that Strabo and the astronomers of that age, who
recognised so clearly the sphericity of the earth and the real
insignificance of mountains, should yet have supposed the stars to have
played so humble a part, but so it was; and we find Strabo arguing in
what we may call quite the contrary direction. He says, "the larger the
mass of water that is spread round the earth, so much more easy is it to
conceive how the vapours arising from it are sufficient to nourish the
heavenly bodies."
[Illustration: FIG. 33.--THE EARTH OF THE LATER GREEKS.]
Among the Latin cosmographers we may here cite one who flourished in the
first century after Christ, Pomponius Mela, who wrote a treatise, called
_De Situ Orbis_. From whatever source, whether traditional or otherwise,
he arrived at the conclusion, he divided the earth into two continents,
our own and that of the Antichthones, which reached to our antipodes.
This map was in use till the time of Christopher Columbus, who modified
it in the matter of the position of this second continent, which till
then remained a matter of mystery.
[Illustration: FIG. 34.--POMPONIUS MELA'S COSMOGRAPHY.]
Of those who in ancient times added to the knowledge then possessed of
cosmography, we should not omit to mention the name of Pytheas, of
Marseilles, who flourished in the fourth century before our era. His
chief observations, however, were not so closely related to geography as
to the relation of the earth with the heavenly bodies. By the
observation of the gnomon at mid-day on the day of the solstice he
determined the obliquity of the ecliptic in his epoch. By the
observation of the height of the pole, he discovered that in his time it
was not marked by any star, but formed a quadrilateral with three
neighbouring stars, [Greek: b] of the little Bear and [Greek: k] and
[Greek: a] of the Dragon.