Popular Science Monthly/Volume 10/March 1877/How the Earth was Regarded in Old Times
|HOW THE EARTH WAS REGARDED IN OLD TIMES.|
WE are too apt in these times of popular education, and the cheap diffusion of knowledge, to forget the cost of scientific truth. We formulate a fact or principle, and administer it in the school-room, with but little regard to the circumstance that it may have cost thousands of years of toil to discover and establish it. We have found out, for example, a great deal about the figure, motions, and astronomical relations of the earth, with such exactness that, as Prof. Young tells us, we know the semi-diameter of our globe at the equator within two hundred feet—while to go "around the world" is now a mere frolic; and all this knowledge is given to children in an hour's lesson. But how few appreciate the long struggle of the human intellect in arriving at these simple results! Let us hastily glance at the early efforts of the human mind in trying to find out what sort of thing this earth is, in its form, extent, and relation to the heavenly bodies that surround it.
The history of the growth of any branch of knowledge has a double interest: that which comes from the knowledge itself, and its relation to the history of the operations of the human mind. Men think under the limitations of their times both as regards the extent of knowledge and the intellectual processes to which they are habituated. They reason as they can on such materials as they have. If they have not learned to observe, they come to conclusions without observations. If they do not know that there are such things as laws of Nature, their inquiries are not directed to find them. If they
think that the mind is the measure of Nature, they will search in their own reflections for the explanations of Nature; and when they have got out plausible results, or which agree with logic, they will impose their conclusions upon Nature as if they represented the truth. The human mind is essentially active and will make theories; and the
less its knowledge the feebler are the restraints of reason and the bolder the spirit of speculation. We must therefore expect that, in regard to the knowledge of the earth when nothing was actually known about it in early times, there must have been an enormous amount of crude conjecture, futile reasoning, and absurd fancy, or rather much that so appears to us now, although it may have been put forth at first as sober and honest belief.
Aristotle, who lived in the fourth century b. c., and studied Nature with great earnestness and assiduity, held many views concerning the earth that were very reasonable for his time. Yet, in the absence of facts, nothing was left for him but to rely upon logic. He had certain ideas of what is natural and what is perfect, and from
these he reasoned as to what must be and therefore what is. To the question whether the earth turns or the heavens turn, he replies that the earth is evidently in repose, not only because we see it to be so, but because it is a necessity that it should be, that is, because repose is natural to the earth. If it be asked why the stars must move around
the earth, he replies, it is natural that they should, because a circle is the most perfect line, because it has no ends, and it must therefore be described by the perfect stars. That the earth is the centre of the universe, and is at rest, is furthermore proved by Aristotle from logical considerations: thus, 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. 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 the centre; the earth is in the centre, and therefore motionless.
Aristotle, however, entertained many sensible views regarding the earth which were of course greatly "in advance of his times," and, among others, that the earth was spherical, for which he offered reasons
that are valid now. But how it could remain suspended in one place without any foundation to rest upon, puzzled him.
Among the various causes which in the absence of facts determined men's geographical opinions, one was the patriotic sentiment by which ignorant people were led to magnify their native country. According to the prepossessions of race, each one thought his own country to be located at the centre of the earth. Thus the Hindoos, who lived near the equator, and the Scandinavians, who lived nearer the pole, apply each a term to their own country which means "the central habitation." The Greeks made Olympus the centre; the Egyptians, Thebes; the Assyrians, Babylon; the Hebrews, Jerusalem; while the Chinese always called their country the central empire. This is natural enough (as Aristotle would say), because most people regard their neighborhood as the centre of the universe, and the number of central railroads shows the continued force of this geometric idea.
One of the most primitive ideas concerning the earth represented it as a vast plain or flat island, surrounded on all sides by an inaccessible and interminable ocean. At the extremities and around the borders were placed the "fortunate isles," or imaginary regions, peopled by giants, pygmies, and extraordinary beings. The circumscribing
water surrounding the irregular outlines of the land led to the idea of a universal ocean. But, when men began to have experience of the sea by early navigation, the idea of a circular horizon always observed led to the notion that the ocean was bounded, and the whole earth came to be represented as contained in a circle, beneath which were roots reaching downward without end.
The priests of Veda, the scriptures of Buddhism, asserted that the earth was supported on twelve columns, which they very ingeniously turned to their own account by asserting that these columns were sustained by virtue of the sacrifices that were made to the gods, so that if these were not made the earth would collapse.
"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 that gradually became enlarged to the intervals between the pillars."
The Hindoos held the earth to be hemispherical, and to be supported like a boat turned upside down upon the heads of four elephants, which stood on the back of an immense tortoise. It is usually said that the tortoise rested on nothing, but the Hindoos maintained that it floated on the surface of the universal ocean. The learned Hindoos, however, say that these animals were merely symbolical, the four elephants meaning the four directions of the compass, and the tortoise meaning eternity. The idea that the earth floated long prevailed, and was adopted by Thales, the early Greek philosopher, and by Seneca several centuries later.
Anaximander, a philosopher of the sixth century before Christ, represented the earth as a cylinder, the upper face alone of which is inhabited. He computed its proportions, and stated that it is one-third as high as its diameter; and he declared that it floats freely in
the centre of the celestial vault, because there is no reason why it should move to one side rather than to the other. Leucippus, Democritus, Heraclitus, and Anaxagoras, all agreed with him, and Anaximenes added the opinion, in consequence of the importance of air in the world, that the earth is supported on compressed air.
Plato was a mathematician, and excogitated the universe out of the depths of his geometrical consciousness. In explaining how things came about, he said that matter in itself had no form or properties, but God in the beginning invested it with a sort of triangular constitution. Afterward, taking a certain number of these primitive triangles, be composed the four primary elements. Fire, the most subtile, is made up of the smallest number of triangles, and has the figure of a pyramid. Water-particles are solids of twenty faces, while the earth-element is cubical or bounded by right-angled triangles. The cube with its six equal faces appeared to Plato to be the most perfect of solids, and therefore most suitable for the earth, which was to stand in the centre of the universe.
How the earth is supported was ever a perplexing question among ignorant nations. Thus, in the opinion of the old Greenlanders, as handed down from antiquity, the earth is upheld by pillars, which are so consumed by time that they often crack, and, were it not that they are sustained by the incantations of the magicians, the earth would long since have broken down.
It is hardly possible for us now to enter into that gross anthropomorphic state of mind by which, in primitive times, the phenomena of the universe were all represented in terms of human personality; nor can we even say how literally such views were held. But certainly
some of the representations are funny and fantastic. Thus, "an ancient Egyptian papyrus in the Library of Paris gives a very curious hieroglyphical representation of the universe. The earth is here imaged under the form of a reclining figure, and is covered with leaves. The heavens are personified by a goddess, who 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."
Strabo, one of the greatest geographers of antiquity—born a. d. 19—held to the sphericity of the earth, but of course regarded it as the motionless centre of the universe. He considered the moon and stars as only meteors, nourished by the exhalations of the ocean, and firmly maintained that no part of the earth can be inhabited save that which was known to the ancients. The form of the habitable world he held to be like that of a cloak, measuring in length from east to west 70,000 stadia (about 8,000 miles), while its breadth is less than 30,000 stadia (3,600 miles). It is bounded by regions habitable, on the one side from excessive heat and on the other from excessive cold. "The habitable world was thus much longer from east to west than it was broad from north to south: whence come our terms longitude, whose degrees are counted in the former direction, and latitude, reckoned in the latter direction."
In the fifth, sixth, and seventh centuries of the Christian era science made little progress in any direction, and, in regard to the ideas of the earth, the fathers of the Church contented themselves with pouring out their invective upon the idea that it is a globe, employing Scriptural reasons, which continued to be used even in the fifteenth century by the monks of Salamanca. In the year a. d. 535, Cosmas, surnamed Indicopleustes, after his voyage to India, wrote a work entitled "Christian Topography," in which he propounded the system of a square earth, with solid walls for supporting the heavens. He undertook to bring the opinions of the fathers into a methodical
shape, and to explain the heavens and the earth in accordance with Scripture. We quote M. Flammarion's description of his system:
"After the fall, Adam was driven from paradise, but he and his descendants remained on the coasts until the deluge carried the ark of Noah to our present earth.
"On the four outsides of the earth rise four perpendicular walls which surround it and join together at the top in a vault, the heavens forming the cupola of this singular edifice.
"The world according to Cosmas was, therefore, a large oblong box, and it was divided into two parts. The first, the abode of men, reaches from the earth
to the firmament, above which the stars accomplish their revolutions; there dwell the angels, who cannot go any higher. The second reaches upward from the firmament to the upper vault, which crowns and terminates the world. On this firmament rest the waters of the heavens.
"Cosmas justifies this system by declaring that, according to the doctrine of the fathers and the commentators on the Bible, the earth has the form of the tabernacle that Moses erected in the desert; which was like an oblong box, twice as long as broad. But we may find other similarities—for this land beyond the ocean recalls the Atlantic of the ancients, and the Mohammedans, and Orientals in general, say that the earth is surrounded by a high mountain, which is a similar idea to the walls of Cosmas.
"God, he says, in creating the earth, rested it on nothing. The earth is, therefore, sustained by the power of God, creator of all things, supporting all things by the word of his power. If below the earth or outside of it anything existed, it would fall of its own accord. So God made the earth the base of the universe, and ordained that it should sustain itself by its own proper gravity."
Cosmas says that the earth, a sort of great square box circumscribed on all sides by high walls, is divided into three parts: first, the habitable earth, which occupies the middle; secondly, the ocean, which surrounds this on all sides; and, thirdly, another dry land, which surrounds the ocean, terminated itself by these high walls, on which the firmament rests. The habitable earth is always higher as we go north, and the southern countries much lower, so that the Tigris and the Euphrates, which run south, are more rapid than the Nile, which runs northward. The sun, moon, planets, and comets, all set behind a large conical mountain; and accordingly as the sun disappears and emerges at points higher or lower is the varying length of day and night. On his view the stars were impelled by angels, who either carried them on their shoulders, rolled them in front of them, or drew them behind, it being remarked that "each angel that pushes a star takes great care to observe what the others are doing, so that the relative distances between the stars may always remain what they ought to be."
The learned Bede, known as the Venerable, who lived in the eighth century, regarded the earth as formed upon the model of an egg. He says:
It is said that a great number of the maps of the world, at the period of Bede, followed this idea, although the necessity was perceived that the great earth-egg should not be left without some kind of support. To meet this requirement Edrisi, an Arabian geographer of the eleventh century, broached the idea that the earth is like an egg, with one-half plunged in water. According to him, the known world forms only a single half of the egg, which floats in the great ocean like an egg in a basin. This notion got currency with artists and map-makers, and continued, it is said, as a mode of representing the earth for many centuries.
"In a manuscript commentary on the Apocalypse, which is in the library of Turin, is a very curious chart, referred to the tenth, but belonging possibly to the eighth century. It represents the earth as a circular planisphere. The four sides of the earth are each accompanied by a figure of a wind, as a horse on a bellows, from which air is poured out, as well as from a shell in his mouth. Above, or to the east, are Adam and Eve, with the serpent. To their right is Asia, with two very elevated mountains—Cappadocia and Caucasus. Thence comes the river Eusis, and the sea into which it falls forms an arm of the ocean which surrounds the earth. This arm joins the Mediterranean, and separates Europe from Asia. Toward the middle is Jerusalem, with two curious arms of the sea running past it; while to the south there is a long and straight sea in an east and west direction. The various islands of the Mediterranean are put in a square patch, and Rome, France, and Germany, are indicated, while Thula, Britannia, and Scotia, are marked as islands in the northwest of the ocean that surrounds the whole world."
And so the history goes on, geographical facts being mingled with fable, superstition, ancient mythology, and modern theology, until the era of maritime discovery, inaugurated by adventurers like Columbus, who discovered a new continent, and Magalhaens, who first circumnavigated the globe. From that period the advance of geographical knowledge has been in a great measure freed from the embarrassments of superstition, and has been steady and rapid in all the various fields of exploration.
- The cuts of this article are from Flammarion's "History of the Heavens," and we have made free use of the text of Blake's "Astronomical Myths," which is based on Flammarion's work.