at the Olympic games with a golden thigh, and | which have stamped his character as the most that he could write in letters of blood whatever subtile and flowery writer of antiquity. At the he pleased on a looking-glass, and that by setting age of twenty, he was introduced to Socrates, it opposite to the moon, when full, all the charac- whose pupil he continued for eight years; and ters which were on the glass became legible on after that great philosopher was unjustly conthe moon's disc. They also support, that, by some demned to death, Plato retired from Athens, and magical words, he tamed a bear, stopped the flight traveled over a large portion of Greece, visiting of an eagle, and appeared on the same day and at Magara, Thebes, and Elis, where he met with the the same instant in the cities of Crotona and kindest reception. Attracted by the fame of the Metapontum, etc.-The time and the place of the Pythagorean philosophy, he afterwards visited death of this great philosopher are unknown; yet Magna Græcia, and thence passed into Sicily to many suppose that he died at Metapontum, about examine the eruptions and fires of the volcano of 497 B. C. and so great was the veneration of the that island. He next went to Egypt, where the people of Magna Græcia for him, that he received accomplished mathematician Theodorus then the same honors as were paid to the immortal gods, flourished, and where he knew that the Pythagoand his house became a sacred temple. Succeed- rean and metempsychosian tenets had been widely ing ages likewise acknowledged his merits; and cherished. After finishing his travels, he settled in when the Romans, A. U. c. 411, were commanded the groves of Academus, near Athens, where his by the oracle of Delphi to erect a statue to the lectures were soon attended by crowds of learned bravest and wisest of the Greeks, the distinguished and noble pupils. With the exception of a brief nonor was conferred on Alcibiades and Pythagoras. absence, during which he was basely betrayed and Plato, whose writings are still held in high esti- sold into slavery by the tyrant Dionysius II. of mation, was a descendant of Codrus,* the last king Syracuse, he presided for forty years at the head of Athens; and, as the offspring of an illustrious of the academy, and there he composed those and opulent family, received an education well Dialogues which have since been the admiration calculated to enlighten his mind and invigorate of every age and country. According to Cicero, his body, and from which he derived that acute- he expired on his birth-day, while writing, aged ness of judgment and warmth of imagination 81 years, about 348 B. c. In his system of the * When the Heraclidæ made war against Athens, the oracle universe, he seems to have wavered between two declared that the victory would be granted to that nation ideas-at one time adopting the theory that the whose king was killed in battle. The Heraclide upon this earth neither rotates nor advances in space, but gave strict orders to spare the life of Codrus, but the patriotic that, fixed to one central point, it merely oscilking disguised himself, and attacked one of the enemy, bylates from side to side; and at another, maintain whom he was killed. The Athenians obtained the victory, and Codrus was deservedly called the father of his country. He reigned 22 years, and was killed 1070 years before the Christian era. To pay greater honor to his memory, the Athenians made a resolution that no man after Codrus should reign in Athens under the name of king, and therefore the government was put into the hands of perpetual archons. ing that the earth is immovable in the centre, which theory was subsequently called the Hipparchian or Ptolemaic. His system of philosophy, however, was in strict accordance with the physics of Heraclitus, the metaphysical opinions he can recover those immaculate powers with which he was naturally endowed. Hicetas, of Syracuse, about 340 B. c., accord ing to Cicero, taught that the sun and stars were motionless, and that the earth moved round them; and although he failed in gaining many proselytes in his own times, his labors have since been justly appreciated. This doctrine nearly proved fatal to him, as he was accused of disturbing the peace of the gods Lares.* He maintained that the sun was nineteen times further distant from the earth than the moon, and that the moon was fifty-six semi-diameters of our globe, a little more than one-third, and the diameter of the sun six or seven times more than that of the earth. The age in which he flourished is not precisely known, but his treatise on the largeness and the distance of the sun and moon is still extant, of which the best edition is that of Oxford, 1688. of Pythagoras, and the morals of Socrates. He maintained the existence of two beings, one selfexistent, and the other formed by the hand of a pre-existent creature, God and man. The world was created by that self-extistent cause, from the rude, undigested mass of matter which had existed from all eternity, and which had even been animated by an irregular principle of motion. The origin of evil could not be traced under the government of a deity, without admitting a stubborn, intractability and wildness congenial to matter; and from these, consequently, could be demonstrated the deviations from the laws of nature, and from thence the extravagant passions and appetites of men. From materials like these were formed the four elements, and the beautiful structure of the heavens and the earth; and into the active but irrational principle of matter, the divinity infused a rational soul. The souls of men were formed from the remainder of the rational soul of the world, which had previously given existence to the invisible gods and demons. The philosopher, therefore, supported the doctrine of ideal forms, and the pre-existence of the human mind, which he considered as emanations of the Deity, which can never remain satisfied with ob-rii, etc. According to the opinion of some, the worship jects or things unworthy of their divine original. Men could perceive with their corporeal senses the types of immutable things, and the fluctuating and from their belief that their spirits continually hovered objects of the material world; but the sudden changes to which these are continually obnoxious, create innumerable disorders, and hence arises deception, and, in short, all the errors and miseries of human life. Yet, in whatever situation man may be, he is still an object of divine concern; and also offered on particular days. Their festivals were observed to recommend himself to the favor of the preexistent cause, he must comply with the purposes of his creation, and by proper care and diligence * At Rome, the gods Lares (two in number, sons of Mercury and Lara) were originally supposed to preside over houses and families. In process of time their power was extended not only over houses, but also over the country and sea; and we find Lares Urbani to preside over the cities, Familiares over roads, Marini over the sea, Viales over the roads, Patellahouses, Rustici over the country. Campitales over cross of the gods Lares, who are supposed to be the same as the Manes, arises from the ancient custom, among the Romans and other nations, of burying their dead in their houses, over the houses for the protection of its inhabitants. The statues of the Lares, resembling monkeys, and covered with the skin of a dog, were placed in a niche behind the doors of the houses, or around the hearths. At the feet of the Lares was the figure of a dog barking, to intimate their care and vigilance. Incense was burned on their altars, and a sow was at Rome in the month of May, when their statues were crowned with garlands of flowers, and offerings of fruit presented. The word Lares seems to be derived from the Etruscan word Lars, which signifies conductor or leader. Aristarchus, of Samos, appears to have been the most prominent philosopher, if not the first, who maintained that the earth not only rotated on its own axis, but also moved round the sun as the centre of the whole planetary system. Seleucus, of Babylon, who lived 150 years after Alexander, and who is mentioned by Strabo 'among several very honorable men, as a Chaldean, skilled in the study of the heavenly bodies," became an advocate of the hypothesis of Aristarchus, which he strenuously endeavored to establish, but met with very little encouragement during his age. in the heavens, were such as appeared marvelous to the ancients, and were esteemed by Pliny as "achievements worthy of a god." He appears to have first conceived the idea of transferring the observed latitudes and longitudes of the stars to their corresponding places on the earth's surfacethus fixing the latter with a degree of precision which no itinerary measurements could ever attain. He made also several observations of latitude, in addition to the very few previously existing, and pointed out the mode of ascertaining longitudes by observing the eclipses of the sun and moon, which he is said to have calculated for 600 years, includHipparchus, of Nice, in Bythnia, whom Hum- ing the moment of their appearance at different boldt calls "the founder of scientific astronomy, places. In his new map of the world, founded and the greatest astronomical observer of anti- upon that of Eratosthenes, the geographical dequity," flourished between 160 and 125 B. C. Hegrees of longitude and latitude were based on lunar first discovered that the interval between the ver- observations and on the measurements of shadows, nal and the autumnal equinox is 186 days, 7 days wherever such an application of astronomical oblonger than between the autumnal and vernal, oc- servations was admissible. But, as the extent of casioned by the eccentricity of the earth's orbit. the earth's surface became developed, it was perHe divided the heavens into 49 constellations-12 ceived how rarely the imperfect method of lunar in the ecliptic, 21 in the northern, and 16 in the eclipses could be employed, and the use of lunar southern hemisphere, and gave names to all the distances was recommended as early as 1514 by stars, but makes no mention of comets. From the Nuremberg astronomer, Johann Werner, and viewing a tree on a plain from different situations, others. Unfortunately, however, these methods which changed its apparent position, he was led to remained impracticable until the mirror-sextant the discovery of the parallax of the planets, or the was invented by the ingenuity of Newton in 1700, distance between their real or apparent position, and was brought into use among scamen by Hadviewed from the centre and from the surface of the ley in 1731. carth. He was the originator of astronomical tables among the Greeks, and likewise made some valuable improvements in geography, by determining the latitudes and longitudes of places from celestial observation, and thereby illustrated the intimate connection which exists between geography and astronomy. His labors in numbering the stars, and arranging them according to their place During the reigns of Adrian and Marcus Antoninus, Claudius Ptolemy, an Egyptian astronomer, geographer, and mathematician, born at Alexandria, A. D. 138, acquired still more celebrity than Hipparchus, though as an astronomer he occupies a far inferior rank. His principal astronomical discovery is the inequality of the moon's motion, technically called the evection; but his fame chiefly rests on his planetary work called "Syntax, or Composition," in which he explains the apparent motion of the sun, moon, and planets, according to an hypothesis invented by Apollonius of Perga, some centuries before, and which consists in supposing each of these bodies to be carried by a uniform motion round the circumference of a circle called the epicycle, the centre of which is carried uniformly forward in the circumference of another circle, called the deferent. This second circle may be the epicycle of a third, and so on, as long as inequalities remain to be explained the earth occupying a position near, but not at, the centre of the last circle. Of course this hypothesis has been demolished by the light of modern science, but in the time of Ptolemy it served to explain all the deviations from circular motion then known, particularly the phenomena of the stations and retrogradations of the planets; and it was even of service to astronomy, by offering a means of reducing the apparent irregularities of the planetary motions to arithmetical calculation. His share of the merit belonging to the invention of this ingenious hypothesis consists in the determination of the proportion between the radius of the epicycle and that of its deferent circle, and between the velocity of the planet and the velocity of the centre of its epicyle. Besides his planetary system and his geography--the last of which is valued for its learning, and will be noticed in another place-he wrote several other books, in one of which is an account of the fixed stars, of which he gives the certain and definite latitude and longitude of 1,022. The Ptolemaic system continued in vogue till the revival of astronomy and the other sciences in the fifteenth century, when it gave place to theories founded on more enlarged views and more accurate observations. Fourteen centuries elapsed between Ptolemy and Copernicus, a Prussian astronomer, born at Thorn in 1472; and during this long interval astronomy made but inconsiderable advances. The elements of the solar and lunar tables had, indeed, received many corrections, and various improvements in the methods of observing and calculating had been introduced, principally by the Arabs; but in respect of theory, no change had taken place. Copernicus, guided perhaps in some measure by the opinions of Pythagoras, but more by his own meditations on the planetary phenomena, in the latter half of the fifteenth century, had the glory of establishing that system of the world which is now universally recognized. The age in which he lived-the age of great maritime enterprises—of Columbus, Gama, and Magellan-wonderfully coincided with many great events: it was characterized by the awakening of a feeling of religious freedom, by the development of nobler sentiments for art, by the unfolding of comparatively illimitable regions hitherto unknown, and by the diffusion of his own inestimable theory regarding the system of the universe. He was engaged in making observations with the astronomer Albert Brudzewski, at Cracow, when Columbus discovered America. He subsequently pursued his investigations at Padua, Bologna, and Rome, in which cities he spent six years, and then returned to Cracow, where he soon became busily engaged in bringing about a thorough revolution in the astronomical views then prevalent. In 1510 he became canon of Frauenburg, where he labored for thirty-one years on the completion of his " De Revolutionibus Orbium Calestium," in which he showed that all the apparent motions are easily explained by simply attributing a double motion to the carth, a diur The doctrine of nal rotation about its axis, and an annual motion | stars that revolve around him.' the earth's motion was opposed to the religious Tycho Brahe, an excellent observer, and one to whom astronomy is under the greatest obligations, made a vain attempt to save the ancient prejudices; but, on account of the physical improbability of his system, he never obtained many followers. Kepler (born in 1571, died in 1630) made the most important step in astronomy by discovering that the orbits of the planets are not circles, but ellipses, having the sun in one of the foci. He also found that the motion of any planet in its elliptic orbit is so regulated, that the spaces passed over by a straight line drawn from the planet to the sun are equal in equal times; and that the periodic times of the different planets are in a certain given ratio to their distances from the sun. This bold and original proposition, combined with the description of equal areas in equal times, led to the discovery of universal gravitation, and all the sublime results of physical astronomy. The idea conceived by Copernicus, and more clearly expressed by Kepler, in his admirable work "De Stella Martis," received a new impulse and a more extended application, through the sagacity of the ingenious Robert Hooke, an English mathematician and astronomer (born in the Isle of Wight, 1635, died in 1702), who not only invented pendulum 'watches, but also several astronomical instruments for making observations both at sea and on land. |