All opinions expressed on the nature of the universe are those of Pliny the Elder
Pliny the Elder, the 'martyr of nature', who died investigating the eruption of Mount Vesuvius in 79 AD, left as his memorial several treatises, including one on the use of the javelin by cavalry and a history of the German wars; but his greatest work, and the only one to survive to the present, was the Natural History (Historia Naturalis), which he completed in 77 A.D. Pliny said that this encyclopaedia of astronomy, meteorology, geography and zoology dealt with 20,000 important subjects from 2,000 works by 100 chosen authors. In fact, a total of 473 authors are quoted. Pliny “deemed every moment lost which was not devoted to study”. Even while he was eating a servant read to him. He has been criticised for his love of 'marvellous' stories, but this is a narrow, hindsight-oriented view. Pliny knew the limitations of human knowledge, and preferred to tell the story and let others judge rather than reject it because it was not a matter of commonplace experience.
Book II of the Natural History deals with the Earth and the Universe (Book I is a table of contents). The Universe is made up of four elements;
Fire, which composes the stars.
Air, the source of life, which permeates all the Universe.
Earth, at the centre of the Universe.
Water; the waters of the Earth.
The Earth is a perfect sphere, and revolves with 'indescribable velocity', once every 24 hours. Although the Earth is at the centre of the Universe, Pliny seemed to consider the Sun a more important body. He calls it the “greatest...the soul, or...the mind of the whole world, the supreme ruling principle and divinity of nature.” The fixed stars are attached to the firmament. They do not influence human fortunes, and are “not assigned to each of us in the way in which the ignorant believe”.
The philosopher Posidonius of Apamea, about 50 BC, aspired to measure the universe. He said that mists, clouds, and winds reach to a height of not less than five miles above the Earth. Beyond this the air is clear, liquid, and luminous. From the cloudy air to the Moon the distance is 250,000 miles and from the moon to the sun 625,000 miles; “it being due to this distance that the Sun's vast magnitude does not burn up the Earth” Pliny was dubious about all such measurements, describing them as 'impudence' based on guesswork.
Between the firmament and the Earth, upheld by the air, are the seven stars called, because of their motion, planetai or wanderers. The planet furthest from the Earth is frozen Saturn, which takes 30 years to complete an orbit. Next comes Jupiter, much below it, as shown by its 12-year orbit. Next comes Mars, also called Hercules; it revolves in about two years, and owing to its nearness to the Sun has a fiery glow.
Next in order of revolution about the Earth is the Sun, a body 'immeasurably large'. The vast size, and the equally vast distance, of the Sun is demonstrated by four facts. Thre shadows of rows of trees are an equal distance apart for many miles. The shadows of those who live on the Tropic of Capricorn all point northwards at midday but westwards at sunrise. During the equinoxes the Sun is overhead at midday for all Tropic of Cancer inhabitants. When the Sun is rising behind Mount Ida near Troy, its disc is visible on each side of the mountain, even though the Sun is so much further away.
Below the Sun revolves the brilliant planet Venus, called by some Juno, and by others Isis. “It surpasses all the other stars in magnitude, and is so brilliant that alone among stars it casts a shadow by its rays.” Venus completes a circuit of the Zodiac every 348 days, and, according to Timaeus, it is never more than 46 degrees away from the Sun. Therefore Venus is only visible before sunrise or after sunset. In ancient times the morning and evening appearances of Venus were thought to be due to different bodies, called Lucifer and Vesper respectively. Pliny says that the fact of their single identity was discovered by Pythagoras of Samos, about 612 BC.
Below Venus is Mercury, or Apollo. It has a similar orbit to Venus, but is much inferior in magnitude, revolving in 339 days and never more than 22 degrees away from the Sun.
The nearest heavenly body to the Earth is the Moon. “By the riddle of her transformations she has racked the wits of observers, who are ashamed that the star which is nearest should be the one about which we know least”. The Moon has the smallest orbit of all the stars, completing one circuit every 27 and a third days. The Moon's light is merely reflected sunlight; this is the reason for her phases. At new Moon she is between us and the Sun, with her dark side turned towards us; at full Moon, we are between the Sun and her, and we see all her illuminated face. Pliny says, “The first human being to observe all these facts about her was Endymion – which accounts for the traditional story of his love for her.” Pliny grumbles, “We forsooth feel no gratitude towards those whose assiduous toil has given us illumination on the subject of this luminary, while owing to a curious disease of the human mind we are pleased to enshrine in history records of bloodshed and slaughter, so that persons ignorant of the facts of the world may be acquainted with the crimes of mankind.”
Eclipses of the Sun and Moon, 'the most marvellous and indeed portentous occurrence in the whole of our observation of nature” are easily explained, Pliny says. Solar eclipses occur when the Moon passes before the Sun, and casts a shadow upon the Earth. They can happen only at new Moon. Lunar eclipses occur when the full Moon passes into the shadow cast by the Earth.
As well as the fixed stars and the planets, sometimes there appear in the heavens 'long-haired stars' or comets. There are many kinds of comets. Pliny describes at least ten different types, in the form of javelins, daggers, torches, quoits and tubs. There is also the mysterious 'Zeus's Comet', a brilliant comet “whose silvery tresses glow so brightly that is scarcely possible to look at it, and which displays within it a shape in the likeness of a man's countenance.” Comets have been visible for up to 80 days, and Aristotle claimed that several have been visible at the same time, “a fact,” Pliny says, 'not observed by anyone else, as far as I am aware”. Some philosophers said that comets were everlasting, and travelled in orbits similar to those of planets. Others believed that they were evanescent creations of moisture and fiery force.
Once, when Germanicus Caesar was giving a show of gladiators, a ball of fire raced across the sky at midday – a meteor. Meteors, according to Pliny, are of two kinds, lampades or torches, and bolides or missiles. Lampades appear as globes of fire, and bolides leave a luminous trail. A bolis was seen in 44 BC, when Decimus Brutus was besieged by Antony at Modena.
Sometimes beams of light, called in Greek dokoi, appear in the northern sky at night. A more terrible appearance is a chasma, when the sky itself seems to open and spill out fire and blood; “the most alarming possible cause of terror to mankind”.
Haloes and Parhelia
Rings of changing colour are sometimes seen around the Sun and Moon. A luminous bow appeared round the Sun in 121 BC, a hoop in 114 BC, and a red ring in 90 BC. At times, false suns are are seen near the Sun. Several suns were once seen at the Bosphorus, and were visible from dawn to sunset. Three suns were seen at once in 174 BC, 118 BC, 44 BC, 42 BC, and in AD 51. In 222 BC, three moons were seen together.
Even more mysterious phenomena have sometimes been recorded. After the murder of Julius Caesar, there was protracted obscuration of the Sun, “which caused a whole year's continuous gloom.” A light from the sky at night, described as a 'night-sun', was seen in 113 BC, and Pliny says that 'apparent daylight in the night' has been seen often on other occasions. In 86 BC, 'a burning shield scattering sparks sped across the sky at sunset from west to east – this was probably a bolis. An unique and hitherto unrecorded phenomenon was the proconsul Sylannus' 'spark' which fell from a star in 66 BC, and grew to the size of the Moon; it illuminated the earth with 'a sort of cloudy daylight', and then returned to the sky in the form of a torch. All these things, Pliny says, “admit of no certain explanation; they are hidden away in the grandeur of nature.”
Surrounding the Earth is the air, which gives humanity the breath of life and causes most of its misfortunes. The air we breathe is a mixture of the heavenly aerial element (ether) and terrestrial vapours. The velocity of the world's rotation creates turmoil in the opposing elements, forming clouds, storms, rain, lightning, hail, frost, and whirlwinds. As the Sun controls the world's seasons, so the other stars create effects upon the Earth according to their nature. It might be argued that the stars are to small to affect the Earth, but Pliny says, “it must not be thought that the stars are of the size they appear to the sight, since the consideration of their immense altitude proves that none of them is smaller than the Moon.” It is a well-known fact that Saturn and the Hyades produce rain, and that the rising of Arcturus is nearly always accompanied by a hailstorm.
Storms, whirlwinds and lightning occur when exhalations rising from the earth fall back, drawing over themselves a curtain of cloud. A widespread downward rush causes a storm. A narrower downrush, which rotates as it descends, forms a tornado, 'shifting from place to place with a rapid whirl'. At sea, this whirl forms a waterspout, fatal to ships. The only defence against a waterspout is to pour vinegar, a very cold substance, before it. Pliny admits that this is a 'slender remedy'. A still narrower downrush, more compressed and hotter, forms a fiery whirlwind called a prester, which as well as “sweeping away the things it comes into contact with, also scorches them up.”
Thunder and Lightning
A very narrow rush, which catches fire as soon as it leaves the cloud, is a lightning flash or thunderbolt. Pliny describes several kinds of thunderbolt. 'Smoky' bolts blacken objects but do not burn them. The most remarkable are the 'bright' thunderbolts: “this kind drains casks dry without damaging their lids and...melts gold and copper and silver in their bags without singeing the bags. A high-born Roman lady, Marcia, was struck by lightning while pregnant. She was unharmed, but the child was killed. Pliny says that man is the only creature who his not always killed when struck by lightning. A man does not die unless the force of the blow turns him right round. Great damage has been done to inanimate objects by lightning; an 'inflammatory' thunderbolt entirely destroyed by fire Bosena, the richest town in Tuscany.
Thunder is the sound of the lightning bolt beginning iots flight, not striking. We see the flash before hearing the sound, “this being not surprising, as light travels faster than sound”.
Other sounds from the sky include “a noise of clanging armour and the sounding of a trumpet” which was heard during the war against the German Cimbrii (103 – 101 BC). Similar sounds from the sky have been often heard before and since.
Matter has frequently fallen from the sky. Pliny gives as examples a rain of milk and blood (114 BC), a fall of unputrefying flesh (461 BC), a fall of sponge-like iron (54 BC), wool and baked bricks (49 BC).
In 467 BC, as a comet shone at night, Anaxagoras of Clazomenae predicted, from his knowledge of astronomy, that in a certain number of days a stone would fall from the Sun. The stone fell in Thrace, but Pliny is dubious about its origin. He says, “our understanding of the physical universe is annihilated...if it is believed either that the Sun is itself a stone or ever had a stone inside it.” He admits that stones have often fallen from the sky.. He says that a fallen stone of 'moderate size' was worshipped at Abydos. Another sacred sky-stone was honoured at Potidaea (from the Greek 'to burn'), where a colony was founded because of the fall. Pliny himself saw a stone which fell from the sky, brought in from the territory of the Vocontii.
Rainbows, unlike sky-stones, are common occurrences. They are too common to be miracles or portents, too common even to be of use in predicting the weather. “The obvious explanation of them is that a ray of the Sun striking a hollow cloud has its point repelled and is reflected back to the Sun, and that the diversified colouring is due to the mixtures of clouds, fires, and air.” Rainbows are always seen opposite the Sun and always in semi-circular form; never more than two are seen at once, and they are never seen at night. (Aristotle says that rainbows are sometimes seen at night, but only when the Moon is more than half full.)
Earth is the only element that is never hostile to man, says Pliny, for “she belongs to man as the sky belongs to God.” Water assails man with waves and torrents of rain, the air rages in storms, but “earth is kind and gentle and indulgent”. Earthquakes and volcanoes might be thought the exception to this rule, but Pliny says the first are caused by imprisoned air and the second by imprisoned fire.
Ocean encircles the earth on every side, 'so robbing us of half the world', although its exact extent is yet unascertained. The poles are uninhabitable, regions of perpetual mist, frost, everlasting cold, and dark for half the year. The torrid zone around the equator is a region of intolerable heat, directly beneath the Sun's orbit and 'scorched by its flames'. Only the two temperate zones, northern and southern, are habitable, and are forever cut off from each other by the fiery torrid zone. Even in the known temperate zone, the north is a region of bitter cold. The races there have cold white skins and yellow hair, and have never known civilisation or governments, “being quite detached and solitary on account of the savagery of the nature that broods over those regions.” The Ethiopians of the south, living near the fiery zone, are “born with a scorched appearance, with curly beard and hair.” The northern races are fierce, the southern wise. Around the Mediterranean, where nature is at its kindest, “customs are gentle, senses clear, intellects fertile and able to grasp the whole of nature.”
There are many marvels of the earth. Some are merely remarkable, such as the two tree-covered floating islands of the great lake of Tarquinni in Italy, which change shape as the wind drives them. Others are dangerous, like the deadly chasms called 'breathing holes' or 'jaws of hell', which exhale a lethal vapour. Near the River Indus are two magnetic mountains, one of which repels iron while the other attracts it. If a man has nails in his shoes, he is unable to set foot on one of the mountains, while on the other he is unable to tear his foot away.
Mountains and Seas
The philosopher Diaerchus, one of Aristotle's disciples, measured the heights of various mountains. The highest was Pelion in Thessaly, with a height of 1,250 paces (over 6,000 feet). This mountain shrinks into insignificance when compared to the Alps. Pliny claims that some Alpine peaks reach a height of at least 50,000 paces (about 24,000 feet).
The sea is nearly two miles deep in places, according to Fabianus. Pliny says that in the Black Sea Deeps, about 37 miles from the coast of the Coraxi tribe, 'soundings have never touched bottom'.
Anaximander of Miletus (d. 547 BC) once warned the Spartans of an impending earthquake. The shock wrecked their city, and a landslide from Mount Taygetus increased the destruction. Pherecydes (d. 515 BC), the tutor of Pythagoras, is said to have predicted an earthquake after observing the condition of water in a well. Pliny says that muddy and foul-smelling well water is one of the premonitory signs of an earthquake. Another is when a thin streak of cloud stretches across the sky in fine weather. During earthquakes, walls collapse, rocks are upthrust, water and fire burst from the earth and rivers are diverted. At sea, vessels are shaken by the shock and sudden waves spring up without wind. Earthquakes are most frequent on coasts, by night, and in autumn and spring. They also occur at a solar eclipse, and when rain follows heat or heat rain.
Earthquakes are preceded and accompanied by a terrible sound. Sometimes it is a rumble, sometimes it resembles the lowing of cattle, or 'the shouts of human beings or the clashing of weapons struck together'. The sound is a clue to the origin of the shock. The subterranean winds which are the cause of earthquakes create different sounds according to the nature of the earth channels they pass through. The earthquake ceases when the subterranean winds find an outlet. If they are unable to, then shocks can continue for up to two years. The imprisoned winds shake the earth in different ways. The least dangerous motion is a quiver and a rising and falling swell. A waving motion or a drive in one direction is dangerous.
In 91 BC, a crowd on the Aemelian road in the district of Modena watched in astonishment as “two mountains ran together with a mighty crash and then fell back. Flames and smoke rose into the sky from the point of impact. The accompanying shock “brought down all the country houses, and a great many animals in the buildings were killed”.
In 217 BC, during the Punic War, 57 earthquakes were reported. One of these, occurring during a battle between Roman and Carthaginian armies at lake Trasimene, went unnoticed by both sides.
Pliny says that the 'greatest earthquake in human memory' was in AD 17, when twelve cities in Asia were overthrown in one night. Earthquakes, as well as being dangerous, were portentous; “the city of Rome was never shaken without this being a premonition of something about to happen.”
New lands are born when a powerful blast of subterranean air is unable to find an outlet. Lost history records that the islands of Delos and Rhodes were born in this way long ago. The island of Pithecusa (now Ischia) rose from the Bay of Campania; later upon it, the mountain Epopos suddenly shot out a great flame and collapsed. In the same bay the island Procidia was thrown up as the result of an earthquake.
Land can also sink back into the sea. Pliny says that the most famous account of this happening is 'if we accept Plato's story', Atlantis, the huge island engulfed by the Atlantic Ocean. The island of Cos suddenly lost over 30,000 paces of land to the sea, together with most of it's inhabitants.
The element of water also has its marvels. The tides, which are caused by the influence of the Sun and the Moon, reach their greatest extent in the World-Ocean, whose vast extent reacts untrammelled to the lunar force. Pytheas of Massalia claimed that north of Britain the tides rose 120 feet. Narrow spaces hinder the Moon's power, which is why lakes and rivers have no tides.
Rivers flow across the surfaces of lakes, or underground, or beneath the sea. Objects thrown into the Greek river Alpheus emerge in the spring of Arethusa in Sicily. Springs are remarkable because, although it is the nature of water to flow downward, they rise upward, emerging even from the roots of fiery Etna. A spring on the island of Andros always has the flavour of wine on January 5th. The day is called locally 'God's Gift Day'. In contrast, three springs on Mount Liberosus in Taurica 'irremediably but painlessly cause death'.
After earth and water, there are the marvels of fire. A marsh at Samosata on the Euphrates produces an inflammable mud called mineral pitch. When this burns water increases the flames, and it can only be extinguished by earth. Naptha, which has an even closer affinity with fire, flows from the earth near Babylon and in Parthia. On the Babylonian Plain naptha blazes in 'a sort of fishpool' an acre in extent, and near Mount Hesperius in Ethiopia, 'the plains shine at night like stars'.
Pliny describes several fiery mountains, most of which seem to be burning as a result of exudations of pitch or naptha. The Mountains of Hephaestus in Lycia burst into flame when touched by a blazing torch, and 'rain only serves to feed the fire'. The largest blaze “is that of the ridge in Ethiopia called the Gods' Carriage, which discharges flames that glow with truly solar heat.”
Eratosthenes, using 'such subtle reasoning that one is ashamed to be sceptical', measured the circumference of the Earth as 252,000 stadia, or 31,500 Roman miles. Despite this, and the fact that the Earth is for Pliny the centre of the universe, the world is nothing but a 'pin-prick' when compared to the extent of the cosmos. “The Earth is nothing else”, Pliny says; “this is the substance of our glory, this is its habitation, here it is that we fill positions of power and covet wealth, and throw mankind into an uproar, and launch even civil wars and slaughter one another to make the land more spacious!” He ends by asking Nature, 'mother of all creation', to favour him, who alone among Rome's citizens has praised her in all her manifestations.