Part 8

In Painting, see Müller's Ancient Art; Fuseli's Lectures; Sir Joshua Reynolds's Lectures; Lanzi's History of Painting in Italy (translated by Roscoe); and the Article on "Painting," Encyclopaedia Britannica, and Article "Pictura," Smith's Dictionary, both of which last mentioned refer to numerous German, French, and other authorities, should the reader care to pursue the subject. Vitruvius (on Architecture, translated by Gwilt) writes at some length on ancient wall-paintings. The finest specimens of ancient paintings are found in catacombs, the baths, and the ruins of Pompeii. On this subject Winckelmann is the great authority.

ANCIENT SCIENTIFIC KNOWLEDGE.

ASTRONOMY, GEOGRAPHY, ETC.

2000-100 B.C.

It would be absurd to claim for the ancients any great attainments in science, such as they made in the field of letters or the realm of art. It is in science, especially when applied to practical life, that the moderns show their great superiority to the most enlightened nations of antiquity. In this great department of human inquiry modern genius shines with the lustre of the sun. It is this which most strikingly attests the advance of civilization. It is this which has distinguished and elevated the races of Europe, and carried them in the line of progress beyond the attainments of the Greeks and Romans. With the magnificent discoveries and inventions of the last three hundred years in almost every department of science, especially in the explorations of distant seas and continents, in the analysis of chemical compounds, in the wonders of steam and electricity, in mechanical appliances to abridge human labor, in astronomical researches, in the explanation of the phenomena of the heavens, in the miracles which inventive genius has wrought,--seen in our ships, our manufactories, our printing-presses, our observatories, our fortifications, our laboratories, our mills, our machines to cultivate the earth, to make our clothes, to build our houses, to multiply our means of offence and defence, to make weak children do the work of Titans, to measure our time with the accuracy of the planetary orbits, to use the sun itself in perpetuating our likenesses to distant generations, to cause a needle to guide the mariner with assurance on the darkest night, to propel a heavy ship against wind and tide without oars or sails, to make carriages ascend mountains without horses at the rate of thirty miles an hour, to convey intelligence with the speed of lightning from continent to continent and under oceans that ancient navigators never dared to cross,--these and other wonders attest an ingenuity and audacity of intellect which would have overwhelmed with amazement the most adventurous of Greeks and the most potent of Romans.

But the great discoveries and inventions to which we owe this marked superiority are either accidental or the result of generations of experiment, assisted by an immense array of ascertained facts from which safe inductions can be made. It is not, probably, the superiority of the European races over the Greeks and Romans to which we may ascribe the wonderful advance of modern society, but the particular direction which genius was made to take. Had the Greeks given the energy of their minds to mechanical forces as they did to artistic creations, they might have made wonderful inventions. But it was not so ordered by Providence. At that time the world was not in the stage of development when this particular direction of intellect could have been favored. The development of the physical sciences, with their infinite multiplicity and complexity, required more centuries of observation, collection and collation of facts, deductions from known phenomena, than the ancients had had to work with; while the more ethereal realms of philosophy, ethics, aesthetics, and religion, though needing keen study of Nature and of man, depended more upon inner spiritual forces, and less upon accumulated detail of external knowledge. Yet as there were some subjects which the Greeks and Romans seemed to exhaust, some fields of labor and thought in which they never have been and perhaps never will be surpassed, so some future age may direct its energies into channels that are as unknown to us as clocks and steam-engines were to the Greeks. This is the age of mechanism and of science; and mechanism and science sweep everything before them, and will probably be carried to their utmost capacity and development. After that the human mind may seek some new department, some new scope for its energies, and an age of new wonders may arise,--perhaps after the present dominant races shall have become intoxicated with the greatness of their triumphs and have shared the fate of the old monarchies of the East. But I would not speculate on the destinies of the European nations, whether they are to make indefinite advances until they occupy and rule the whole world, or are destined to be succeeded by nations as yet undeveloped,--savages, as their fathers were when Rome was in the fulness of material wealth and grandeur.

I have shown that in the field of artistic excellence, in literary composition, in the arts of government and legislation, and even in the realm of philosophical speculation, the ancients were our school-masters, and that among them were some men of most marvellous genius, who have had no superiors among us. But we do not see among them the exhibition of genius in what we call science, at least in its application to practical life. It would be difficult to show any department of science which the ancients carried to any considerable degree of perfection. Nevertheless, there were departments in which they made noble attempts, and in which they showed large capacity, even if they were unsuccessful in great practical results.

Astronomy was one of these. In this science such men as Eratosthenes, Aristarchus, Hipparchus, and Ptolemy were great lights of whom humanity may be proud; and had they been assisted by our modern inventions, they might have earned a fame scarcely eclipsed by that of Kepler and Newton. The old astronomers did little to place this science on a true foundation, but they showed great ingenuity, and discovered some truths which no succeeding age has repudiated. They determined the circumference of the earth by a method identical with that which would be employed by modern astronomers; they ascertained the position of the stars by right ascension and declination; they knew the obliquity of the ecliptic, and determined the place of the sun's apogee as well as its mean motion. Their calculations on the eccentricity of the moon prove that they had a rectilinear trigonometry and tables of chords. They had an approximate knowledge of parallax; they could calculate eclipses of the moon, and use them for the correction of their lunar tables. They understood spherical trigonometry, and determined the motions of the sun and moon, involving an accurate definition of the year and a method of predicting eclipses; they ascertained that the earth was a sphere, and reduced the phenomena of the heavenly bodies to uniform movements of circular orbits. We have settled by physical geography the exact form of the earth, but the ancients arrived at their knowledge by astronomical reasoning. Says Whewell:--

"The reduction of the motions of the sun, moon, and five planets to circular orbits, as was done by Hipparchus, implies deep concentrated thought and scientific abstraction. The theories of eccentrics and epicycles accomplished the end of explaining all the known phenomena. The resolution of the apparent motions of the heavenly bodies into an assemblage of circular motions was a great triumph of genius, and was equivalent to the most recent and improved processes by which modern astronomers deal with such motions."

Astronomy was probably born in Chaldaea as early as the time of Abraham. The glories of the firmament were impressed upon the minds of the rude primitive races with an intensity which we do not feel, with all the triumphs of modern science. The Chaldaean shepherds, as they watched their flocks by night, noted the movements of the planets, and gave names to the more brilliant constellations. Before religious rituals were established, before great superstitions arose, before poetry was sung, before musical instruments were invented, before artists sculptured marble or melted bronze, before coins were stamped, before temples arose, before diseases were healed by the arts of medicine, before commerce was known, those Oriental shepherds counted the anxious hours by the position of certain constellations. Astronomy is therefore the oldest of the ancient sciences, although it remained imperfect for more than four thousand years. The old Assyrians, Egyptians, and Greeks made but few discoveries which are valued by modern astronomers, but they laid the foundation of the science, and ever regarded it as one of the noblest subjects that could stimulate the faculties of man. It was invested with all that was religious and poetical.

The spacious level and unclouded horizon of Chaldaea afforded peculiar facilities of observation; and its pastoral and contemplative inhabitants, uncontaminated by the vices and superstitions of subsequent ages, active-minded and fresh, discovered after a long observation of eclipses--some say extending over nineteen centuries--the cycle of two hundred and twenty-three lunations, which brings back the eclipses in the same order. Having once established their cycle, they laid the foundation for the most sublime of all the sciences. Callisthenes transmitted from Babylon to Aristotle a collection of observations of all the eclipses that preceded the conquests of Alexander, together with the definite knowledge which the Chaldaeans had collected about the motions of the heavenly bodies. Such knowledge was rude and simple, and amounted to little beyond the fact that there were spherical revolutions about an inclined axis, and that the poles pointed always to particular stars. The Egyptians also recorded their observations, from which it would appear that they observed eclipses at least sixteen hundred years before the beginning of our era,--which is not improbable, if the speculations of modern philosophers respecting the age of the world are entitled to credit. The Egyptians discovered by the rising of Sirius that the year consists of three hundred and sixty-five and one-quarter days; and this was their sacred year, in distinction from the civil, which consisted of three hundred and sixty-five days. They also had observed the courses of the planets, and could explain the phenomena of the stations and retrogradations; and it is asserted too that they regarded Mercury and Venus as satellites of the sun. Some have maintained that the obelisks which the Egyptians erected served the purpose of gnomons for determining the obliquity of the ecliptic, the altitude of the pole, and the length of the tropical year. It is thought even that the Pyramids, by the position of their sides toward the cardinal points, attest Egyptian acquaintance with a meridional line. The Chinese boast of having noticed and recorded a series of eclipses extending over a period of thirty-eight hundred and fifty-eight years; and it is probable that they anticipated the Greeks two thousand years in the discovery of the Metonic cycle,--or the cycle of nineteen years, at the end of which time the new moons fall on the same days of the year. The Chinese also determined the obliquity of the ecliptic eleven hundred years before our era. The Hindus at a remote antiquity represented celestial phenomena with considerable exactness, and constructed tables by which the longitude of the sun and moon were determined, and dials to measure time. Bailly thinks that thirty-one hundred and two years before Christ astronomy was cultivated in Siam which hardly yields in accuracy to that which modern science has built on the theory of universal gravitation.

But the Greeks after all were the only people of antiquity who elevated astronomy to the dignity of a science. They however confessed that they derived their earliest knowledge from the Babylonian and Egyptian priests, while the priests of Thebes claimed to be the originators of exact astronomical observations. Diodorus asserts that the Chaldaeans used the Temple of Belus, in the centre of Babylon, for their survey of the heavens. But whether the Babylonians or the Egyptians were the earliest astronomers is of little consequence, although the pedants make it a grave matter of investigation. All we know is that astronomy was cultivated by both Babylonians and Egyptians, and that they made but very limited attainments. They approximated to the truth in reference to the solar year, by observing the equinoxes and solstices and the heliacal rising of particular stars.

The early Greek philosophers who visited Egypt and the East in search of knowledge, found very little to reward their curiosity or industry,--not much beyond preposterous claims to a high antiquity, and to an esoteric wisdom which has not yet been revealed. Plato and Eudoxus spent thirteen years in Heliopolis for the purpose of extracting the scientific knowledge of the Egyptian priests, yet they learned but little beyond the fact that the solar year was a trifle beyond three hundred and sixty-five days. No great names have come down to us from the priests of Babylon or Egypt; no one gained an individual reputation. The Chaldaean and Egyptian priests may have furnished the raw material of observation to the Greeks, but the latter alone possessed the scientific genius by which undigested facts were converted into a symmetrical system. The East never gave valuable knowledge to the West; it gave the tendency to religious mysticism, which in its turn tended to superstition. Instead of astronomy, it gave astrology; instead of science, it gave magic, incantations, and dreams. The Eastern astronomers connected their astronomy with divination from the stars, and made their antiquity reach back to two hundred and seventy thousand years. There were soothsayers in the time of Daniel, and magicians, exorcists, and interpreters of signs. They were not men of scientific research, seeking truth; it was power they sought, by perverting the intellect of the people. The astrology of the East was founded on the principle that a star or constellation presided over the birth of an individual, and that it either portended his fate, or shed a good or bad influence upon his future life. The star which looked upon a child at the hour of his birth was called the "horoscopus," and the peculiar influence of each planet was determined by the astrologers. The superstitions of Egypt and Chaldaea unfortunately spread among both the Greeks and Romans, and these were about all that the Western nations learned from the boastful priests of occult Oriental science. Whatever was known of real value among the ancients is due to the earnest inquiries of the Greeks.

And yet their researches were very unsatisfactory until the time of Hipparchus. The primitive knowledge was almost nothing. The Homeric poems regarded the earth as a circular plain bounded by the heaven, which was a solid vault or hemisphere, with its concavity turned downward. This absurdity was believed until the time of Herodotus, five centuries after; nor was it exploded fully in the time of Aristotle. The sun, moon, and stars were supposed to move upon or with the inner surface of the heavenly hemisphere, and the ocean was thought to gird the earth around as a great belt, into which the heavenly bodies sank at night. Homer believed that the sun arose out of the ocean, ascended the heaven, and again plunged into the ocean, passing under the earth, and producing darkness. The Greeks even personified the sun as a divine charioteer driving his fiery steeds over the steep of heaven, until he bathed them at evening in the western waves. Apollo became the god of the sun, as Diana was the goddess of the moon. But the early Greek inquirers did not attempt to explain how the sun found his way from the west back again to the east; they merely took note of the diurnal course, the alternation of day and night, the number of the seasons, and their regular successions. They found the points of the compass by determining the recurrence of the equinoxes and solstices; but they had no conception of the ecliptic,--of that great circle in the heaven formed by the sun's annual course,--and of its obliquity when compared with our equator. Like the Egyptians and Babylonians, the Greeks ascertained the length of the year to be three hundred and sixty-five days; but perfect accuracy was lacking, for want of scientific instruments and of recorded observations of the heavenly bodies. The Greeks had not even a common chronological era for the designation of years. Herodotus informs us that the Trojan War preceded his time by eight hundred years: he merely states the interval between the event in question and his own time; he had certain data for distant periods. The Greeks reckoned dates from the Trojan War, and the Romans from the building of their city. The Greeks also divided the year into twelve months, and introduced the intercalary circle of eight years, although the Romans disused it afterward, until the calendar was reformed by Julius Caesar. Thus there was no scientific astronomical knowledge worth mentioning among the primitive Greeks.

Immense research and learning have been expended by modern critics to show the state of scientific astronomy among the Greeks. I am amazed equally at the amount of research and its comparative worthlessness; for what addition to science can be made by an enumeration of the puerilities and errors of the Greeks, and how wasted and pedantic the learning which ransacks all antiquity to prove that the Greeks adopted this or that absurdity!

The earliest historic name associated with astronomy in Greece was Thales, the founder of the Ionic school of philosophers. He is reported to have made a visit to Egypt, to have fixed the year at three hundred and sixty-five days, to have determined the course of the sun from solstice to solstice, and to have calculated eclipses. He attributed an eclipse of the moon to the interposition of the earth between the sun and moon, and an eclipse of the sun to the interposition of the moon between the sun and earth,--and thus taught the rotundity of the earth, sun, and moon. He also determined the ratio of the sun's diameter to its apparent orbit. As he first solved the problem of inscribing a right-angled triangle in a circle, he is the founder of geometrical science in Greece. He left, however, nothing to writing; hence all accounts of him are confused,--some doubting even if he made the discoveries attributed to him. His philosophical speculations, which science rejects,--such as that water is the principle of all things,--are irrelevant to a description of the progress of astronomy. That he was a great light no one questions, considering the ignorance with which he was surrounded.

Anaximander, who followed Thales in philosophy, held to puerile doctrines concerning the motions and nature of the stars, which it is useless to repeat. His addition to science, if he made any, was in treating the magnitudes and distances of the planets. He constructed geographical charts, and attempted to delineate the celestial sphere, and to measure time with a gnomon, or time-pillar, by the motion of its shadow upon a dial.

Anaximenes of Miletus taught, like his predecessors, crude notions of the sun and stars, and speculated on the nature of the moon, but did nothing to advance his science on true grounds, except by the construction of sun-dials. The same may be said of Heraclitus, Xenophanes, Parmenides, and Anaxagoras: they were great men, but they gave to the world mere speculations, some of which are very puerile. They all held to the idea that the heavenly bodies revolved around the earth, and that the earth was a plain; but they explained eclipses, and supposed that the moon derived its light from the sun. Some of them knew the difference between the planets and the fixed stars. Anaxagoras scouted the notion that the sun was a god, and supposed it to be a mass of ignited stone,--for which he was called an atheist.

Socrates, who belonged to another school, avoided all barren speculations concerning the universe, and confined himself to human actions and interests. He looked even upon geometry in a very practical way, valuing it only so far as it could be made serviceable to land-measuring. As for the stars and planets, he supposed it was impossible to arrive at a true knowledge of them, and regarded speculations upon them as useless.

It must be admitted that the Greek astronomers, however barren were their general theories, laid the foundation of science. Pythagoras taught the obliquity of the ecliptic, probably learned in Egypt, and the identity of the morning and evening stars. It is supposed that he maintained that the sun was the centre of the universe, and that the earth revolved around it; but this he did not demonstrate, and his whole system was unscientific, assuming certain arbitrary principles, from which he reasoned deductively. "He assumed that fire is more worthy than earth; that the more worthy place must be given to the more worthy; that the extremity is more worthy than the intermediate parts,--and hence, as the centre is an extremity, the place of fire is at the centre of the universe, and that therefore the earth and other heavenly bodies move round the fiery centre." But this was no heliocentric system, since the sun moved, like the earth, in a circle around the central fire. This was merely the work of the imagination, utterly unscientific, though bold and original. Nor did this hypothesis gain credit, since it was the fixed opinion of philosophers that the earth was the centre of the universe, around which the sun, moon, and planets revolved. But the Pythagoreans were the first to teach that the motions of the sun, moon, and planets are circular and equable. Their idea that the celestial bodies emitted a sound, and were combined into a harmonious symphony, was exceedingly crude, however beautiful "The music of the spheres" belongs to poetry, as well as to the speculations of Plato.

Eudoxus, in the fifth century before Christ, contributed to science by making a descriptive map of the heavens, which was used as a manual of sidereal astronomy to the sixth century of our era.

The error of only one hundred and ninety days in the periodic time of Saturn shows that there had been for a long time close observations. Aristotle--whose comprehensive intellect, like that of Bacon, took in all forms of knowledge--condensed all that was known in his day into a treatise concerning the heavens. He regarded astronomy as more intimately connected with mathematics than any other branch of science. But even he did not soar far beyond the philosophers of his day, since he held to the immobility of the earth,--the grand error of the ancients. Some few speculators in science (like Heraclitus of Pontus, and Hicetas) conceived a motion of the earth itself upon its axis, so as to account for the apparent motion of the sun; but they also thought it was in the centre of the universe.

The introduction of the gnomon (time-pillar) and dial into Greece advanced astronomical knowledge, since they were used to determine the equinoxes and solstices, as well as parts of the day. Meton set up a sun-dial at Athens in the year 433 B.C., but the length of the hour varied with the time of the year, since the Greeks divided the day into twelve equal parts. Dials were common at Rome in the time of Plautus, 224 B.C.; but there was a difficulty in using them, since they failed at night and in cloudy weather, and could not be relied on. Hence the introduction of water-clocks instead.

Aristarchus is said to have combated (280 B.C.) the geocentric theory so generally received by philosophers, and to have promulgated the hypothesis "that the fixed stars and the sun are immovable; that the earth is carried round the sun in the circumference of a circle of which the sun is the centre; and that the sphere of the fixed stars, having the same centre as the sun, is of such magnitude that the orbit of the earth is to the distance of the fixed stars as the centre of the sphere of the fixed stars is to its surface." Aristarchus also, according to Plutarch, explained the apparent annual motion of the sun in the ecliptic by supposing the orbit of the earth to be inclined to its axis. There is no evidence that this great astronomer supported his heliocentric theory with any geometrical proof, although Plutarch maintains that he demonstrated it. This theory gave great offence, especially to the Stoics; and Cleanthes, the head of the school at that time, maintained that the author of such an impious doctrine should be punished. Aristarchus left a treatise "On the Magnitudes and Distances of the Sun and Moon;" and his methods to measure the apparent diameters of the sun and moon are considered theoretically sound by modern astronomers, but practically inexact owing to defective instruments. He estimated the diameter of the sun at the seven hundred and twentieth part of the circumference of the circle which it describes in its diurnal revolution, which is not far from the truth; but in this treatise he does not allude to his heliocentric theory.

Archimedes of Syracuse, born 287 B.C., is stated to have measured the distance of the sun, moon, and planets, and he constructed an orrery in which he exhibited their motions. But it was not in the Grecian colony of Syracuse, but of Alexandria, that the greatest light was shed on astronomical science. Here Aristarchus resided, and also Eratosthenes, who lived between the years 276 and 196 B.C. The latter was a native of Athens, but was invited by Ptolemy Euergetes to Alexandria, and placed at the head of the library. His great achievement was the determination of the circumference of the earth. This was done by measuring on the ground the distance between Syene, a city exactly under the tropic, and Alexandria, situated on the same meridian. The distance was found to be five thousand stadia. The meridional distance of the sun from the zenith of Alexandria he estimated to be 7° 12', or a fiftieth part of the circumference of the meridian. Hence the circumference of the earth was fixed at two hundred and fifty thousand stadia,--which is not very different from our modern computation. The circumference being known, the diameter of the earth was easily determined. The moderns have added nothing to this method. He also calculated the diameter of the sun to be twenty-seven times greater than that of the earth, and the distance of the sun from the earth to be eight hundred and four million stadia, and that of the moon seven hundred and eighty thousand stadia,--a close approximation to the truth.

Astronomical science received a great impulse from the school of Alexandria, the greatest light of which was Hipparchus, who flourished early in the second century before Christ. He laid the foundation of astronomy upon a scientific basis. "He determined," says Delambre, "the position of the stars by right ascensions and declinations, and was acquainted with the obliquity of the ecliptic. He determined the inequality of the sun and the place of its apogee, as well as its mean motion; the mean motion of the moon, of its nodes and apogee; the equation of the moon's centre, and the inclination of its orbit. He calculated eclipses of the moon, and used them for the correction of his lunar tables, and he had an approximate knowledge of parallax." His determination of the motions of the sun and moon, and his method of predicting eclipses evince great mathematical genius. But he combined with this determination a theory of epicycles and eccentrics which modern astronomy discards. It was however a great thing to conceive of the earth as a solid sphere, and to reduce the phenomena of the heavenly bodies to uniform motions in circular orbits. "That Hipparchus should have succeeded in the first great steps of the resolution of the heavenly bodies into circular motions is a circumstance," says Whewell, "which gives him one of the most distinguished places in the roll of great astronomers." But he did even more than this: he discovered that apparent motion of the fixed stars round the axis of the ecliptic, which is called the Precession of the Equinoxes,--one of the greatest discoveries in astronomy. He maintained that the precession was not greater than fifty-nine seconds, and not less than thirty-six seconds. Hipparchus also framed a catalogue of the stars, and determined their places with reference to the ecliptic by their latitudes and longitudes. Altogether he seems to have been one of the greatest geniuses of antiquity, and his works imply a prodigious amount of calculation.

Astronomy made no progress for three hundred years, although it was expounded by improved methods. Posidonius constructed an orrery, which exhibited the diurnal motions of the sun, moon, and five planets. Posidonius calculated the circumference of the earth to be two hundred and forty thousand stadia, by a different method from Eratosthenes. The barrenness of discovery from Hipparchus to Ptolemy,--the Alexandrian mathematician, astronomer, and geographer in the second century of the Christian era,--in spite of the patronage of the royal Ptolemies of Egypt, was owing to the want of instruments for the accurate measure of time (like our clocks), to the imperfection of astronomical tables, and to the want of telescopes. Hence the great Greek astronomers were unable to realize their theories. Their theories however were magnificent, and evinced great power of mathematical combination; but what could they do without that wondrous instrument by which the human eye indefinitely multiplies its power? Moreover, the ancients had no accurate almanacs, since the care of the calendar belonged not so much to the astronomers as to the priests, who tampered with the computation of time for sacerdotal objects. The calendars of different communities differed. Hence Julius Caesar rendered a great service to science by the reform of the Roman calendar, which was exclusively under the control of the college of pontiffs, or general religious overseers. The Roman year consisted of three hundred and fifty-five days; and in the time of Caesar the calendar was in great confusion, being ninety days in advance, so that January was an autumn month. He inserted the regular intercalary month of twenty-three days, and two additional ones of sixty-seven days. These, together with ninety days, were added to three hundred and sixty-five days, making a year of transition of four hundred and forty-five days, by which January was brought back to the first month in the year after the winter solstice; and to prevent the repetition of the error, he directed that in future the year should consist of three hundred and sixty-five and one-quarter days, which he effected by adding one day to the months of April, June, September, and November, and two days to the months of January, Sextilis, and December, making an addition of ten days to the old year of three hundred and fifty-five. And he provided for a uniform intercalation of one day in every fourth year, which accounted for the remaining quarter of a day.

Caesar was a student of astronomy, and always found time for its contemplation. He is said even to have written a treatise on the motion of the stars. He was assisted in his reform of the calendar by Sosigines, an Alexandrian astronomer. He took it out of the hands of the priests, and made it a matter of pure civil regulation. The year was defined by the sun, and not as before by the moon.