Meteorological (Aristotle) ​​- Wikipedia

The Treaty of Meteorological (in ancient Greek Meteorological ) is a work composed by Aristotle, in four books. In the etymological sense of Greek meteor / meta , it is a study of celestial bodies and phenomena that occur in an average area between the moon and the earth. Aristotle mainly studies the exhalations sometimes “Dry and smoking” which result from the action of the sun on the earth, sometimes “Wet and vaporous” When this action occurs on water or on a wet earth ^{[ first ]} . Thus, phenomena like winds, lightning, lightning, broken down, snow, hail etc. are explained, but often arbitrarily. We cannot consider the work as a treaty of meteorology in the modern sense of the term.

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According to Aristotle, the terrestrial world is a mass of spherical form made up of four elements: the earth, then the water which covers it, both that of the sea and that of the continents, the air, the fire finally, different from the Earth’s fire, and which is the product of the circular movement of the upper region in contact with air. Beyond these four elements, Aristotle admits the presence of ether, hypothesis of which he is the inventor. But it is based on mythical tradition to assert the prehistoric existence of this notion ^{[ 2 ]} . He considers the globe as the center of the world but admits its small size, and its distance from the sun and the other stars. For him, the earth is only a point in the universe, which has not been made for it ^{[ 3 ]} .

All “meteors”, that is to say celestial phenomena, are produced by the action of the four elements, especially water and air, by the heat of the sun and by universal movement. Thus, the water evaporates constantly, and it rises in this form in the higher regions of the atmosphere, to descend soon in various forms. The air also contains another no less important part than steam, namely secretion, which escapes from the land. Of these “meteors”, some are substantial (rain, snow, hail, dew), others are only appearances and games of light (halo, parhel, rainbow) ^{[ 4 ]} .

Aristotle begins with the phenomena which happens in the most distant regions and first makes the theory of Compets and the Milky Way, then is interested in the “meteors” which are closer to us: the atmospheric ocean, the formation of clouds and fog, dew, white jelly, rain, snow, hail, on which it stops a little longer ^{[ 5 ]} .

He then began a digression on the formation of water on the surface of the globe. He proves that the greatest rivers always take their sources at the foot of the highest mountains. It deals with continuous encroachments of waters on firm land and firm land on the waters, the secular slowness of these great changes, and the uncertainty of traditions, due to the inevitable brevity of human memories, migrations of peoples succeeding itself without transmitting the memory of the upheavals that occurred, cause of these migrations ^{[ 6 ]} .

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Aristotle maintains against Democritus that the current state of the seas dates back to the beginning of the world. The sea has no sources like rivers, but it has been established, from the outset, as a kind of traffic where the marine waters evaporating provide the material of rains, and where the rain provides The material of rivers, which give sea what they have received at sea. It then deals with sea water and made several observations: seawater vapor does not contain salinity, sea water is heavier than fresh water ^{[ 7 ]} .

Then he proceeds to the theory of winds, whose formation he reports to the exhalation which crosses the atmosphere, and to the heat of the sun. The motor principle of the winds is found in the high parts of the sky; The material is provided by dry exhalation, which comes out of the earth. The violence of the winds and the properties that distinguish them depend a lot from the places they blow. The habitable land really forms two areas, one below, the other beyond the equator, and separated by the hot area, where men can no longer live because of the stifling heat of these countries. Thus, the South Wind does not come, from the pole opposite to our Boréal pole, it comes from the hot area and does not exceed it ^{[ 8 ]} .

He declares that earthquakes are the action of air disturbances, not in the atmosphere, but in the breast of the terrestrial globe. And lightning, thunder, lightning, hurricane and trompe, are the diverse action of exhalations, either dry or humid ^{[ 9 ]} .

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Finally he explains the phenomena caused by light and which are basically only appearances: Halo, Parélie, “luminous yards”, and especially the rainbow. The latter is a simple refraction effect. Aristotle had undertook long and meticulous observations on the mirrors, and he had noticed that, in a host of cases, especially when the facets of the mirrors are extremely small, the mirror reproduces the color without reproducing the shape. It starts from this principle to affirm that the droplets of the clouds make, with regard to sunlight, the mirror office, and that they refract it, without the very figure of the star being reproduced there ^{[ ten ]} .

The rainbow has only three well-sized colors, purple, green and red. Yellow, which is also sometimes in a fairly striking way, only results from the contrast of neighboring colors. Sometimes there are two rainbows instead of one; But in the second, the colors are always paler; And in addition, they are stored in a reverse order. A very remarkable feature of the rainbow, and which distinguishes it from halo, is that it never forms a semicircle without reaching a greater development. As the sun rises on the horizon, to reach the meridian, the rainbow decreases, and it grows more and more, as the sun declines; But in no case can it exceed the semi-circular ^{[ 11 ]} .

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The fourth book is apocryphal and has sometimes been attributed to Straton de Lampsaque ^{[ twelfth ]} . This is the first attempt at chemistry in antiquity. It illustrates the difficulty encountered by Aristotle’s disciples in resolving the question of the constitution of matter by retaining the relationship between second cause (in Greek conference ) and final cause; The atomist theory of Democritus therefore becomes a working hypothesis ^{[ 13 ]} . This book deals with substances in general, and is moving away from meteorology. Of the four properties of the elements, two are active, cold and hot; Two are passive, dry and wet. The cold and the heat, combining or disaggregating humid and dry, form all the varied bodies that we observe. Describe these bodies, coagulating or liquidating themselves under the action of hot and cold, solidifying or fusion, etc. , it is still the work of meteorology. According to the author of this book IV, this study is an essential preparation for that of substances, either homogeneous or non-homogenic, of which plants are made up and even animals ^{[ 14 ]} .

All the meteorology of the ancients rested on the treaty of Aristotle, especially perhaps through theophrastus ^{[ 15 ]} . Strabo, Posidonios d’Apa, Ératosthene, Lucrèce, Sénèque and Pliny the Ancient studied and cited the Meteorological ^{[ 16 ]} ; Alexander of Aphrodise, Olympiodorus, and Jean Philopon commented them ^{[ 17 ]} . In modern times, it is still the fund on which medieval meteorology lives, and even that of Descartes for everything it owes in the Middle Ages ^{[ 15 ]} .

• Aristote ( you. ) ( trad.  Jocelyn Groisard & Pierre Pellegrin), “Meteorological” , In Complete Works , Flammarion editions, 2014 , 2923 p. (ISBN  978-2081273160 ) .
• Léon Robin, Aristote , Paris, P.U.F., 1944 ( read online ) , p. 113 to 121: “Astronomy and cosmology” . .

• Meteorology , translation of Jean Barthélémy Saint-Hilaire, Paris, 1863, Google Books .
• Meteorological , in two volumes, edition and translation of P. Louis, Les Belles Lettres, 2002.
• Meteorological , Edition and translation of Pierre Thillet, Gallimard, 2008.
• Meteorological , Translation of Jocelyn Groisard, Garnier-Flammarion, 2008.