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PYRUVIC ACID, or PYRORACEMIC ACID

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Originally appearing in Volume V22, Page 700 of the 1911 Encyclopedia Britannica.
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PYRUVIC See also:

ACID, or PYRORACEMIC ACID  , See also:CH3COSee also:CO2H, an organic See also:acid first obtained by J . See also:Berzelius by the dry See also:distillation of tartaric or racemic acids (Pogg . See also:Ann., 1835, 36, p . I) . It may be prepared by boiling a-dichlorpropionic acid with See also:silver See also:oxide; by the See also:hydrolysis of acetyl See also:cyanide with hydrochloric acid (J . Claisen and J . See also:Shadwell, Ber., 1878 . Ir, pp . 62o, 1563); and by warming oxalacetic ester with a so% See also:solution of sulphuric acid . It is usually made by distilling tartaric acid with See also:potassium bisulphate at about 200—250° C., the crude product being after-wards fractionated . It is a liquid which boils at about 165° C . (with partial decomposition) ; it may be solidified, and when pure melts at 13.6° C .

(L . See also:

Simon See also:Bull . See also:Soc . Chim., 1895 [31, 13, p . 335) . It is readily soluble in See also:water, See also:alcohol and See also:ether . It reduces ammoniacal silver solutions . When heated with hydrochloric acid to See also:loo° C. it yields See also:carbon dioxide and pyrotartaric acid, C5H804, and when warmed with dilute sulphuric acid to 15o° C. it gives carbon dioxide and acetaldehyde . See also:Sodium See also:amalgam or See also:zinc and hydrochloric acid reduce it to lactic acid, whilst hydriodic acid gives propionic acid . It readily condenses with aromatic See also:hydrocarbons in the presence of sulphuric acid . It is somewhat readily oxidized; nitric acid gives carbonic and oxalic acids, and chromic acid, carbonic and acetic acids . It forms a well-crystallized See also:hydrazone with phenylhydrazine; and a-nitroso but this entanglement with politics led in the end to the dismemberment and suppression of the society .

The authorities differ hopelessly in See also:

chronology, but according to the See also:balance of See also:evidence the first reaction against the Pythagoreans took See also:place in the lifetime of See also:Pythagoras after the victory gained by See also:Crotona over See also:Sybaris in 5io . Dissensions seem to have arisen about the See also:allotment of the conquered territory, and an adverse party was formed in Crotona under the leadership of Cylon . This was probably the cause of Pythagoras's withdrawal to See also:Metapontum, which an almost unanimous tradition assigns as the place of his See also:death in the end of the 6th or the beginning of the 5th See also:century . The See also:order appears to have continued powerful in Magna Graecia till the See also:middle of the 5th century, when it was violently trampled out . The See also:meeting-houses of the Pythagoreans were everywhere sacked and burned; mention is made in particular of "the See also:house of See also:Milo" in Crotona, where fifty or sixty leading Pythagoreans were surprised and slain . The persecution to which the brotherhood was subjected throughout Magna Graecia was the immediate cause of the spread of the See also:Pythagorean See also:philosophy in See also:Greece proper . See also:Philolaus, who resided at See also:Thebes in the end of the 5th century (cf . See also:Plato, See also:Phaedo, 6i D), was the author of the first written exposition of the See also:system . Lysis, the instructor of See also:Epaminondas, was another of these refugees . This Theban Pythagoreanism had an important See also:influence upon Plato's thought, and Philolaus had also disciples in the stricter sense . But as a philosophic school Pythagoreanism became See also:extinct in Greece about the middle of the 4th century . In See also:Italy-where, after a temporary suppression, it attained a new importance in the See also:person of See also:Archytas of See also:Tarentum—the school finally disappeared about the same See also:time .

See also:

Aristotle in his accounts of Pythagorean doctrines never refers to Pythagoras but always with a studied vagueness to " the Pythagoreans" (oi rcaXouµovoc HvOayopewi) . Nevertheless, certain doctrines may be traced to the founder's teaching . Foremost among these is the -theory of the See also:immortality and transmigration of the soul (see See also:METEMPSYCHOSIS) . Pythagoras's teaching on this point is connected by one of the most trustworthy authorities with the See also:doctrine of the kinship of all living beings; and in the See also:light of anthropological See also:research it is easy to recognize the See also:close relationship of the two beliefs . The Pythagorean See also:rule of See also:abstinence from flesh is thus, in its origin, a See also:taboo resting upon the See also:blood-brotherhood of men and beasts; and the same See also:line of thought shows a number of the Pythagorean rules of See also:life which we find embedded in the different traditions to be genuine taboos belonging to a similar level of See also:primitive thought . The moral and religious application which Pythagoras gave to the doctrine of transmigration continued to be the teaching of the school . The view of the See also:body (u& a) as the See also:tomb (o ia) of the soul, and the See also:account of philosophy in the Phaedo as a meditation of death, are expressly connected by Plato with the teaching of Philolaus; and the See also:strain of See also:asceticism and other worldliness which meets us here and elsewhere in Plato is usually traced to Pythagorean influence . Plato's mythical descriptions of a future life of retribution and purificatory wandering can also be shown to reproduce Pythagorean teaching, though the sub-stance of them may have been See also:drawn from a See also:common source in the Mysteries . The scientific doctrines of the Pythagorean school have no apparent connexion with the religious See also:mysticism of the society or their rules of living . They have their origin in the same disinterested See also:desire of knowledge which gave rise to the other philosophical See also:schools of Greece, and the See also:idea of " philosophy " or the "theoretic life" as a method of emancipation from the evils of See also:man's See also:present See also:state of existence, though a genuine Pythagorean conception, is clearly an afterthought . The discourses and speculations of the Pythagoreans all connect themselves with the idea of number, and the school holds an important place in the See also:history of mathematical and astronomical See also:science . An unimpeached tradition carries back the Pythagorean theory of See also:numbers to the teaching of the founder himself .

Phoenix-squares

Working on hints contained in the See also:

oldest traditions, See also:recent investigators have shown that the discoveries attributed to Pythagoras connect themselves with a primitive numerical symbolism, according to which numbers were represented by dots arranged in symmetrical patterns, such as are still to be seen in the marking of See also:dice or See also:dominoes . Each See also:pattern of See also:units becomes on this See also:plan a fresh unit . The " See also:holy tetractys," by which the later Pythagoreans used to swear, was a figure of this See also:kind representing the number to as the triangle of 4, and showing at a glance that I + 2 + 3 + 4 = 10 . The sums of the See also:series of any successive numbers may be graphically represented in a similar way, and are hence spoken of as " triangular numbers," while the sums of the series of successive See also:odd numbers are called " square numbers," and those of successive even numbers "oblong numbers"; thus 3 and 5 added to the unit give a figure of this description -.1 . while 4 and 6, added to 2, are thus • represented .1 - Such a method of representing number in areas leads naturally to problems of a geometrical nature, and as the See also:practical use of the right-angled triangle was already See also:familiar in the arts and crafts, there is no See also:reason to dispute the well-established tradition which assigns to Pythagoras the See also:discovery of the See also:pro-position that in such a triangle the square on the hypotenuse is equal to the sum of the squares on the other two sides . And it is probably also correct to attribute to him the discovery of the See also:harmonic intervals which underlie the See also:production of musical sounds . Impressed by this reduction of musical sounds to numbers and by the presence of numerical relations in every See also:department of phenomena, Pythagoras and his See also:early followers enunciated the doctrine that " all things are numbers." Numbers seemed to them, as Aristotle put it, to be the first things in the whole of nature, and they supposed the elements of numbers to be the elements of all things, and the whole See also:heaven to be a musical See also:scale and a number (See also:Meta . A . 986a) . Numbers, in other words, were conceived at that early See also:stage of thought not as relations or qualities predicable of things, but as themselves constituting the substance or essence of the phenomena—the rational reality to which the appearances of sense are reducible . But the development of these ideas into a comprehensive meta-See also:physical system was no doubt the See also:work of Philolaus in the latter See also:part of the 5th century . His formulation of the theory implies a knowledge of the teaching of Parmenides and See also:Empedocles, and had itself in turn a See also:great influence upon Plato . The " elements of numbers," of which Aristotle speaks in the passage quoted above, were, according to the Pythagoreans, the Odd and the Even, which they identified with the Limit and the Unlimited; and Aristotle distinctly says that they did not treat these as " priorities of certain other substances" such as See also:fire, water or anything else of that sort, but that the unlimited itself and the one were the reality of the things of which they were predicated, and that is why they said that number was " the reality of everything " (Meta .

A . 587) . Numbers, therefore, are spatially conceived, " one " being identified with the point in the sense of a unit having position and magnitude . From combinations of such units the higher numbers and geometrical figures arise—" two " being identified with the line, " three " with the See also:

surface, and " four " with the solid—and the Pythagoreans proceeded to explain the elements of Empedocles as built up out of geometrical figures in the manner followed by Plato in the See also:Timaeus . The See also:identification of the numerical opposites, the Odd and the Even, with the Limit and the Unlimited—otherwise difficult to explain—may perhaps be understood, as See also:Burnet suggests, by reference to the arrangement of the units or "terms" (8poi) in patterns . " When the odd is divided into two equal parts," he quotes from See also:Stobaeus, " a unit is See also:left over in the middle; but when the even is so divided, an empty See also:field is left over, without a See also:master and without a number, showing that it is defective and incomplete." The idea of opposites, derived, perhaps, originally from Heracleitus, was See also:developed by the Pythagoreans in a See also:list of ten fundamental oppositions, bearing a certain resemblance to the tables of categories framed by later philosophers, but in its arbitrary mingling of mathematical, physical and ethical contrasts characteristic of the uncritical beginnings of speculative thought: (I) limited and unlimited, (2) odd and even, (3)one and many,(4)right and left, (5) male and See also:female, (6) See also:rest and See also:motion, (7) straight and curved, (8) light and darkness, (9) See also:good and evil, (to) square and oblong . To the Pythagoreans, as to Heracleitus, the universe was in a sense the realized See also:union of these opposites, but interpretations of Pythagoreanism which represent the whole system as founded on the opposition of unity and duality, and proceed to identify this with the opposition of See also:form and See also:matter, of divine activity and passive material, betray on the surface their See also:post-Platonic origin . Still more is this the See also:case when in Neoplatonic See also:fashion they go on to derive this See also:original opposition from the supreme unity or See also:God . The further speculations of the Pythagoreans on the subject of number rest mainly on analogies, which often become capricious and tend to lose themselves at last in a barren symbolism . " Seven" is called aap8Evos and 'AOitv,t, because within the See also:decade it has neither factors nor product . " Five," on the other See also:hand, signifies See also:marriage, because it is the union of the first masculine with the first feminine number (3+2, unity being considered as a number apart) . The thought already becomes more fanciful when " one " is identified with reason, because it is unchangeable; " two " with See also:opinion, because it is unlimited and indeterminate; " four " with See also:justice, because it is the first square number, the product of equals .

The See also:

astronomy of the Pythagoreans was their most notable contribution to scientific thought, and its importance lies in the fact that they were the first to conceive the See also:earth as a globe, self-supported in empty space, revolving with the other See also:planets See also:round a central luminary . They thus anticipated the See also:heliocentric theory, and See also:Copernicus has left it on See also:record that the Pythagorean doctrine of the planetary See also:movement of the earth gave him the first hint of its true See also:hypothesis . The Pythagoreans did not, however, put the See also:sun in the centre of the system . That place was filled by the central fire to which they gave the names of See also:Hestia, the See also:hearth of the universe, the See also:watch-See also:tower of See also:Zeus, and other mythological expressions . It had then been recently discovered that the See also:moon shone by reflected light, and the Pythagoreans (adapting a theory of Empedocles), explained the light of the sun also as due to reflection from the central fire . Round this fire revolve ten bodies, first the Antichthon or See also:counter-earth, then the earth, followed in order by the moon, the sun, the five then known planets and the heaven of the fixed stars . The central fire and the counter-earth are invisible to us because the See also:side of the earth on which we live is always turned away from them, and our light and See also:heat come to us, as already stated, by reflection from the sun . When the earth is on the same side of the central fire as the sun, the side of the earth on which we live is turned towards the sun and we have See also:day; when the earth and the sun are on opposite sides of the central fire we are turned away from the sun and it is See also:night . The distance of the revolving orbs from the central fire was determined according to See also:simple numerical relations, and the Pythagoreans combined their astronomical and their musical discoveries in the famous doctrine of " the See also:harmony of the See also:spheres." The velocities of the bodies depend upon their distances from the centre, the slower and nearer bodies giving out a deep See also:note and the swifter a high note, the See also:concert of the whole yielding the See also:cosmic See also:octave . The reason why we do not hear this See also:music is that we are like men in a See also:smith's forge, who cease to be aware of a See also:sound which they constantly hear and are never in a position to contrast with silence . AuTHoRITrns.—See also:Zeller's account of Pythagoreanism in his Philosophie der Griechen gives a full account of the See also:sources, with See also:critical references in the notes to the numerous monographs on the subject, but the labour and ingenuity of more recent scholars has succeeded in clearing up a number of points since he wrote . Diels, Doxographi graeci (1879), and See also:Die Fragmente der Vorsokratiker, vol. i .

(2nd ed., 1906) . See also:

Gomperz, See also:Greek Thinkers, vol. i., and especially Burnet's Early Greek Philosophy (2nd ed., 1908), give the results of the latest investigations . Tannery's Science hellene; Milhaud's La . Science grecque and Philosophes geometees; Cantor's History of See also:Mathematics; and See also:Gow's See also:Short History of Greek Mathematics, refer to the mathematical and physical doctrines of the school . (A . S .

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