LOGOCYCLIC CURVE

logocyclic curve, strophoid or foliate, a cubic curve generated by increasing or diminishing the radius vector of a variable point q on a straight line ab by the distance qc of the point from the foot of the perpendicular drawn from the origin to the fixed line. the polar equation is r cos[theta] = a(1 ± sin[theta]), the upper sign referring to the case when the vector is increased, the lower when it is diminished. both branches are included in the cartesian equation (x2 + y2)(2a - x) = a2x, where a is the distance of the line from the origin. if we take for axes the fixed line and the perpendicular through the initial point, the equation takes the form y [root](a - x) = x [root](a + x). the curve resembles the folium of descartes, and has a node between x = 0, x = a, and two branches asymptotic to the line x = 2a. [illustration.] logographi ([greek: logos], [greek: grapho], writers of prose histories or tales), the name given by modern scholars to the greek historiographers before herodotus.[1] thucydides, however, applies the term to all his own predecessors, and it is therefore usual to make a distinction between the older and the younger logographers. their representatives, with one exception, came from ionia and its islands, which from their position were most favourably situated for the acquisition of knowledge concerning the distant countries of east and west. they wrote in the ionic dialect, in what was called the unperiodic style, and preserved the poetic character of their epic model. their criticism amounts to nothing more than a crude attempt to rationalize the current legends and traditions connected with the founding of cities, the genealogies of ruling families, and the manners and customs of individual peoples. of scientific criticism there is no trace whatever. the first of these historians was probably cadmus of miletus (who lived, if at all, in the early part of the 6th century), the earliest writer of prose, author of a work on the founding of his native city and the colonization of ionia (so suidas); pherecydes of leros, who died about 400, is generally considered the last. mention may also be made of the following: hecataeus of miletus (550-476); acusilaus of argos,[2] who paraphrased in prose (correcting the tradition where it seemed necessary) the genealogical works of hesiod in the ionic dialect; he confined his attention to the prehistoric period, and made no attempt at a real history; charon of lampsacus (c. 450), author of histories of persia, libya, and ethiopia, of annals ([greek: horoi]) of his native town with lists of the prytaneis and archons, and of the chronicles of lacedaemonian kings; xanthus of sardis in lydia (c. 450), author of a history of lydia, one of the chief authorities used by nicolaus of damascus (_fl._ during the time of augustus); hellanicus of mytilene; stesimbrotus of thasos, opponent of pericles and reputed author of a political pamphlet on themistocles, thucydides and pericles; hippys and glaucus, both of rhegium, the first the author of histories of italy and sicily, the second of a treatise on ancient poets and musicians, used by harpocration and plutarch; damastes of sigeum, pupil of hellanicus, author of genealogies of the combatants before troy (an ethnographic and statistical list), of short treatises on poets, sophists, and geographical subjects. on the early greek historians, see g. busolt, _griechische geschichte_ (1893), i. 147-153; c. wachsmuth, _einleitung in das studium der alten geschichte_ (1895); a. schafer, _abriss der quellenkunde der griechischen und romischen geschichte_ (ed. h. nissen, 1889); j. b. bury, _ancient greek historians_ (1909), lecture i.; histories of greek literature by muller-donaldson (ch. 18) and w. mure (bk. iv. ch. 3), where the little that is known concerning the life and writings of the logographers is exhaustively discussed. the fragments will be found, with latin notes, translation, prolegomena, and copious indexes, in c. w. muller's _fragmenta historicorum graecorum_ (1841-1870). see also greece: _history, ancient_ (section, "authorities"). footnotes: [1] the word is also used of the writers of speeches for the use of the contending parties in the law courts, who were forbidden to employ advocates. [2] there is some doubt as to whether this acusilaus was of peloponnesian or boeotian argos. possibly there were two of the name. for an example of the method of acusilaus see bury, _op. cit._ p. 19. logos [greek: logos], a common term in ancient philosophy and theology. it expresses the idea of an immanent reason in the world, and, under various modifications, is met with in indian, egyptian and persian systems of thought. but the idea was developed mainly in hellenic and hebrew philosophy, and we may distinguish the following stages: 1. _the hellenic logos._--to the greek mind, which saw in the world a [greek: kosmos] (ordered whole), it was natural to regard the world as the product of reason, and reason as the ruling principle in the world. so we find a logos doctrine more or less prominent from the dawn of hellenic thought to its eclipse. it rises in the realm of physical speculation, passes over into the territory of ethics and theology, and makes its way through at least three well-defined stages. these are marked off by the names of heraclitus of ephesus, the stoics and philo. it acquires its first importance in the theories of heraclitus (6th century b.c.), who, trying to account for the aesthetic order of the visible universe, broke away to some extent from the purely physical conceptions of his predecessors and discerned at work in the cosmic process a [greek: logos] analogous to the reasoning power in man. on the one hand the logos is identified with [greek: gnome] and connected with [greek: dike], which latter seems to have the function of correcting deviations from the eternal law that rules in things. on the other hand it is not positively distinguished either from the ethereal fire, or from the [greek: heimarmene] and the [greek: ananke] according to which all things occur. heraclitus holds that nothing material can be thought of without this logos, but he does not conceive the logos itself to be immaterial. whether it is regarded as in any sense possessed of intelligence and consciousness is a question variously answered. but there is most to say for the negative. this logos is not one above the world or prior to it, but in the world and inseparable from it. man's soul is a part of it. it is _relation_, therefore, as schleiermacher expresses it, or reason, not speech or word. and it is objective, not subjective, reason. like a law of nature, objective in the world, it gives order and regularity to the movement of things, and makes the system rational.[1] the failure of heraclitus to free himself entirely from the physical hypotheses of earlier times prevented his speculation from influencing his successors. with anaxagoras a conception entered which gradually triumphed over that of heraclitus, namely, the conception of a supreme, intellectual principle, not identified with the world but independent of it. this, however, was [greek: nous], not logos. in the platonic and aristotelian systems, too, the theory of ideas involved an absolute separation between the material world and the world of higher reality, and though the term logos is found the conception is vague and undeveloped. with plato the term selected for the expression of the principle to which the order visible in the universe is due is [greek: nous] or [greek: sophia], not [greek: logos]. it is in the pseudo-platonic _epinomis_ that [greek: logos] appears as a synonym for [greek: nous]. in aristotle, again, the principle which sets all nature under the rule of thought, and directs it towards a rational end, is [greek: nous], or the divine spirit itself; while [greek: logos] is a term with many senses, used as more or less identical with a number of phrases, [greek: ou heneka], [greek: energeia], [greek: entelecheia], [greek: ousia], [greek: eidos], [greek: morphe], &c. in the reaction from platonic dualism, however, the logos doctrine reappears in great breadth. it is a capital element in the system of the stoics. with their teleological views of the world they naturally predicated an active principle pervading it and determining it. this operative principle is called both logos and god. it is conceived of as material, and is described in terms used equally of nature and of god. there is at the same time the special doctrine of the [greek: logos spermatikos], the seminal logos, or the law of generation in the world, the principle of the active reason working in dead matter. this parts into [greek: logoi spermatikoi], which are akin, not to the platonic ideas, but rather to the [greek: logoi enuloi] of aristotle. in man, too, there is a logos which is his characteristic possession, and which is [greek: endiathetos], as long as it is a thought resident within his breast, but [greek: prophorikos] when it is expressed as a word. this distinction between logos as ratio and logos as _oratio_, so much used subsequently by philo and the christian fathers, had been so far anticipated by aristotle's distinction between the [greek: exo logos] and the [greek: logos en te psyche]. it forms the point of attachment by which the logos doctrine connected itself with christianity. the logos of the stoics (q.v.) is a reason in the world gifted with intelligence, and analogous to the reason in man. 2. _the hebrew logos._--in the later judaism the earlier anthropomorphic conception of god and with it the sense of the divine nearness had been succeeded by a belief which placed god at a remote distance, severed from man and the world by a deep chasm. the old familiar name yahweh became a secret; its place was taken by such general expressions as the holy, the almighty, the majesty on high, the king of kings, and also by the simple word "heaven." instead of the once powerful confidence in the immediate presence of god there grew up a mass of speculation regarding on the one hand the distant future, on the other the distant past. various attempts were made to bridge the gulf between god and man, including the angels, and a number of other hybrid forms of which it is hard to say whether they are personal beings or abstractions. the wisdom, the shekinah or glory, and the spirit of god are intermediate beings of this kind, and even the law came to be regarded as an independent spiritual entity. among these conceptions that of the word of god had an important place, especially the creative word of genesis i. here as in the other cases we cannot always say whether the word is regarded as a mere attribute or activity of god, or an independent being, though there is a clear tendency towards the latter. the ambiguity lies in the twofold purpose of these activities: (1) to establish communication with god; (2) to prevent direct connexion between god and the world. the word of the god of revelation is represented as the creative principle (e.g. gen. i. 3; psalm xxxiii. 6), as the executor of the divine judgments (hosea vi. 5), as healing (psalm cvii. 20), as possessed of almost personal qualities (isaiah lv. 11; psalm cxlvii. 15). along with this comes the doctrine of the angel of yahweh, the angel of the covenant, the angel of the presence, in whom god manifests himself, and who is sometimes identified with yahweh or elohim (gen. xvi. 11, 13; xxxii. 29-31; exod. iii. 2; xiii. 21), sometimes distinguished from him (gen. xxii. 15, &c.; xxiv. 7; xxviii. 12, &c.), and sometimes presented in both aspects (judges ii., vi.; zech. i.). to this must be added the doctrine of wisdom, given in the books of job and proverbs. at one time it is exhibited as an attribute of god (prov. iii. 19). at another it is strongly personified, so as to become rather the creative thought of god than a quality (prov. viii. 22). again it is described as proceeding from god as the principle of creation and objective to him. in these and kindred passages (job xv. 7, &c.) it is on the way to become hypostatized. the hebrew conception is partially associated with the greek in the case of aristobulus, the predecessor of philo, and, according to the fathers, the founder of the alexandrian school. he speaks of wisdom in a way reminding us of the book of proverbs. the pseudo-solomonic _book of wisdom_ (generally supposed to be the work of an alexandrian flourishing somewhere between aristobulus and philo) deals both with the wisdom and with the logos. it fails to hypostatize either. but it represents the former as the framer of the world, as the power or spirit of god, active alike in the physical, the intellectual, and the ethical domain, and apparently objective to god. in the targums, on the other hand, the three doctrines of the word, the angel, and the wisdom of god converge in a very definite conception. in the jewish theology god is represented as purely transcendent, having no likeness of nature with man, and making no personal entrance into history. instead of the immediate relation of god to the world the targums introduce the ideas of the _memra_ (word) and the _shechina_ (real presence). this memra (= ma'amar) or, as it is also designated, _dibbura_, is a hypostasis that takes the place of god when direct intercourse with man is in view. in all those passages of the old testament where anthropomorphic terms are used of god, the memra is substituted for god. the memra proceeds from god, and retains the creaturely relation to god. it does not seem to have been identified with the messiah.[2] 3. _philo._--in the alexandrian philosophy, as represented by the hellenized jew philo, the logos doctrine assumes a leading place and shapes a new career for itself. philo's doctrine is moulded by three forces--platonism, stoicism and hebraism. he detaches the logos idea from its connexion with stoic materialism and attaches it to a thoroughgoing platonism. it is plato's idea of the good regarded as creatively active. hence, instead of being merely immanent in the cosmos, it has an independent existence. platonic too is the doctrine of the divine architect who seeks to realize in the visible universe the archetypes already formed in his mind. philo was thus able to make the logos theory a bridge between judaism and greek philosophy. it preserved the monotheistic idea yet afforded a description of the divine activity in terms of hellenic thought; the word of the old testament is one with the [greek: logos] of the stoics. and thus in philo's conception the logos is much more than "the principle of reason, informing the infinite variety of things, and so creating the world-order"; it is also the divine dynamic, the energy and self-revelation of god. the stoics indeed sought, more or less consciously, by their doctrine of the logos as the infinite reason to escape from the belief in a divine creator, but philo, jew to the core, starts from the jewish belief in a supreme, self-existing god, to whom the reason of the world must be subordinated though related. the conflict of the two conceptions (the greek and the hebrew) led him into some difficulty; sometimes he represents the logos as an independent and even personal being, a "second god," sometimes as merely an aspect of the divine activity. and though passages of the first class must no doubt be explained figuratively--for philo would not assert the existence of two divine agents--it remains true that the two conceptions cannot be fused. the alexandrian philosopher wavers between the two theories and has to accord to the logos of hellas a semi-independent position beside the supreme god of judaea. he speaks of the logos (1) as the agency by which god reveals himself, in some measure to all men, in greater degree to chosen souls. the appearances recorded in the old testament are manifestations of the logos, and the knowledge of god possessed by the great leaders and teachers of israel is due to the same source; (2) as the agency whereby man, enmeshed by illusion, lays hold of the higher spiritual life and rising above his partial point of view participates in the universal reason. the logos is thus the means of redemption; those who realize its activity being emancipated from the tyranny of circumstance into the freedom of the eternal. 4. _the fourth gospel._--among the influences that shaped the fourth gospel that of the alexandrian philosophy must be assigned a distinct, though not an exaggerated importance. there are other books in the new testament that bear the same impress, the epistles to the ephesians and the colossians, and to a much greater degree the epistle to the hebrews. the development that had thus begun in the time of paul reaches maturity in the fourth gospel, whose dependence on philo appears (1) in the use of the allegorical method, (2) in many coincident passages, (3) in the dominant conception of the logos. the writer narrates the life of christ from the point of view furnished him by philo's theory. true, the logos doctrine is only mentioned in the prologue to the gospel, but it is presupposed throughout the whole book. the author's task indeed was somewhat akin to that of philo, "to transplant into the world of hellenic culture a revelation originally given through judaism." this is not to say that he holds the logos doctrine in exactly the same form as philo. on the contrary, the fact that he starts from an actual knowledge of the earthly life of jesus, while philo, even when ascribing a real personality to the logos, keeps within the bounds of abstract speculation, leads him seriously to modify the philonic doctrine. though the alexandrian idea largely determines the evangelist's treatment of the history, the history similarly reacts on the idea. the prologue is an organic portion of the gospel and not a preface written to conciliate a philosophic public. it assumes that the logos idea is familiar in christian theology, and vividly summarizes the main features of the philonic conception--the eternal existence of the logos, its relation to god ([greek: pros ton theon], yet distinct), its creative, illuminative and redemptive activity. but the adaptation of the idea to john's account of a historical person involved at least three profound modifications:--(1) the logos, instead of the abstraction or semi-personification of philo, becomes fully personified. the word that became flesh subsisted from all eternity as a distinct personality within the divine nature. (2) much greater stress is laid upon the redemptive than upon the creative function. the latter indeed is glanced at ("all things were made by him"), merely to provide a link with earlier speculation, but what the writer is concerned about is not the mode in which the world came into being but the spiritual life which resides in the logos and is communicated by him to men. (3) the idea of [greek: logos] as reason becomes subordinated to the idea of [greek: logos] as word, the expression of god's will and power, the outgoing of the divine energy, life, love and light. thus in its fundamental thought the prologue of the fourth gospel comes nearer to the old testament (and especially to gen. i.) than to philo. as speech goes out from a man and reveals his character and thought, so christ is "sent out from the father," and as the divine word is also, in accordance with the hebrew idea, the medium of god's quickening power. what john thus does is to take the logos idea of philo and use it for a practical purpose--to make more intelligible to himself and his readers the divine nature of jesus christ. that this endeavour to work into the historical tradition of the life and teaching of jesus--a hypothesis which had a distinctly foreign origin--led him into serious difficulties is a consideration that must be discussed elsewhere. 5. _the early church._--in many of the early christian writers, as well as in the heterodox schools, the logos doctrine is influenced by the greek idea. the syrian gnostic basilides held (according to irenaeus i. 24) that the logos or word emanated from the [greek: nous], or personified reason, as this latter emanated from the unbegotten father. the completest type of gnosticism, the valentinian, regarded wisdom as the last of the series of aeons that emanated from the original being or father, and the logos as an emanation from the first two principles that issued from god, reason ([greek: nous]) and truth. justin martyr, the first of the sub-apostolic fathers, taught that god produced of his own nature a rational power([greek: dynamin tina logiken]), his agent in creation, who now became man in jesus (_dial. c. tryph._ chap. 48, 60). he affirmed also the action of the [greek: logos spermatikos], (_apol._ i. 46; ii. 13, &c.). with tatian (_cohort. ad. gr._ chap. 5, &c.) the logos is the beginning of the world, the reason that comes into being as the sharer of god's rational power. with athenagoras (_suppl._ chap. 9, 10) he is the prototype of the world and the energizing principle ([greek: idea kai energeia]) of things. theophilus (ad _autolyc._ ii. 10, 24) taught that the logos was in eternity with god as the [greek: logos endiathetos], the counsellor of god, and that when the world was to be created god sent forth this counsellor ([greek: symboulos]) from himself as the [greek: logos prophorikos], yet so that the begotten logos did not cease to be a part of himself. with hippolytus (_refut._ x. 32, &c.) the logos, produced of god's own substance, is both the divine intelligence that appears in the world as the son of god, and the idea of the universe immanent in god. the early sabellians (comp. eusebius, _hist. eccl._ vi. 33; athanasius, _contra arian._ iv.) held that the logos was a faculty of god, the divine reason, immanent in god eternally, but not in distinct personality prior to the historical manifestation in christ. origen, referring the act of creation to eternity instead of to time, affirmed the eternal personal existence of the logos. in relation to god this logos or son was a copy of the original, and as such inferior to that. in relation to the world he was its prototype, the [greek: idea ideon] and its redeeming power (_contra cels._ v. 608; _frag. de princip._ i. 4; _de princip._ i. 109, 324). in the later developments of hellenic speculation nothing essential was added to the doctrine of the logos. philo's distinction between god and his rational power or logos in contact with the world was generally maintained by the eclectic platonists and neo-platonists. by some of these this distinction was carried out to the extent of predicating (as was done by numenius of apamea) three gods:--the supreme god; the second god, or demiurge or logos; and the third god, or the world. plotinus explained the logoi as constructive forces, proceeding from the ideas and giving form to the dead matter of sensible things (_enneads_, v. 1. 8 and richter's _neu-plat. studien_). see the histories of philosophy and theology, and works quoted under heraclitus, stoics, philo, john, the gospel of, &c., and for a general summary of the growth of the logos doctrine, e. caird, _evolution of theology in the greek philosophers_ (1904), vol. ii.; a. harnack, _history of dogma_; e. f. scott, _the fourth gospel_, ch. v. (1906); j. m. heinze, _die lehre vom logos in der griech. philosophie_ (1872); j. reville, _la doctrine du logos_ (1881); aal, _gesch. d. logos-idee_ (1899); and the _histories of dogma_, by a. harnack, f. loofs, r. seeberg. (s. d. f. s.; a. j. g.) footnotes: [1] cf. schleiermacher's _herakleitos der dunkle_; art. heraclitus and authorities there quoted. [2] cf. the targum of onkelos on the pentateuch under gen. vii. 16, xvii. 2, xxi. 20; exod. xix. 16, etc.; the jerusalem targum on numb. vii. 89, &c. for further information regarding the hebrew _logos_ see, beside dr kaufmann kohler, s.v. "memra," _jewish encyc._ viii. 464-465, bousset, _die religion des judenthums_ (1903), p. 341, and weber, _judische theologie_ (1897), pp. 180-184. the hypostatizing of the divine word in the doctrine of the memra was probably later than the time of philo, but it was the outcome of a mode of thinking already common in jewish theology. the same tendency is of course expressed in the "logos" of the fourth gospel. logothete (med. lat. _logotheta_, gr. [greek: logothetes], from [greek: logos], word, account, calculation, and [greek: tithenai], to set, i.e. "one who accounts, calculates or ratiocinates"), originally the title of a variety of administrative officials in the byzantine empire, e.g. the [greek: logothetes tou dromou], who was practically the equivalent of the modern postmaster-general; and the [greek: logothetes tou stratiotikou], the logothete of the military chest. gibbon defines the great logothete as "the supreme guardian of the laws and revenues," who "is compared with the chancellor of the latin monarchies." from the eastern empire the title was borrowed by the west, though it only became firmly established in sicily, where the _logotheta_ occupied the position of chancellor elsewhere, his office being equal if not superior to that of the _magnus cancellarius_. thus the title was borne by pietro della vigna, the all-powerful minister of the emperor frederick ii., king of sicily. see du cange, _glossarium_, s.v. _logotheta_. logrono, an inland province of northern spain, the smallest of the eight provinces formed in 1833 out of old castile; bounded n. by burgos, alava and navarre, w. by burgos, s. by soria and e. by navarre and saragossa. pop. (1900) 189,376; area, 1946 sq. m. logrono belongs entirely to the basin of the river ebro, which forms its northern boundary except for a short distance near san vicente; it is drained chiefly by the rivers tiron, oja, najerilla, iregua, leza, cidacos and alhama, all flowing in a north-easterly direction. the portion skirting the ebro forms a spacious and for the most part fertile undulating plain, called la rioja, but in the south logrono is considerably broken up by offshoots from the sierras which separate that river from the douro. in the west the cerro de san lorenzo, the culminating point of the sierra de la demanda, rises 7562 ft., and in the south the pico de urbion reaches 7388 ft. the products of the province are chiefly cereals, good oil and wine (especially in the rioja), fruit, silk, flax and honey. wine is the principal export, although after 1892 this industry suffered greatly from the protective duties imposed by france. great efforts have been made to keep a hold upon french and english markets with light red and white rioja wines. no less than 128,000 acres are covered with vines, and 21,000 with olive groves. iron and argentiferous lead are mined in small quantities and other ores have been discovered. the manufacturing industries are insignificant. a railway along the right bank of the ebro connects the province with saragossa, and from miranda there is railway communication with madrid, bilbao and france; but there is no railway in the southern districts, where trade is much retarded by the lack even of good roads. the town of logrono (pop. 1900, 19,237) and the city of calahorra (9475) are separately described. the only other towns with upwards of 5000 inhabitants are haro (7914), alfaro (5938) and cervera del rio alhama (5930). logrono, the capital of the spanish province of logrono, on the right bank of the river ebro and on the saragossa-miranda de ebro railway. pop. (1900) 19,237. logrono is an ancient walled town, finely situated on a hill 1204 ft. high. its bridge of twelve arches across the ebro was built in 1138, but has frequently been restored after partial destruction by floods. the main street, arcaded on both sides, and the crooked but highly picturesque alleys of the older quarters are in striking contrast with the broad, tree-shaded avenues and squares laid out in modern times. the chief buildings are a bull-ring which accommodates 11,000 spectators, and a church, santa maria de palacio, called "the imperial," from the tradition that its founder was constantine the great (274-337). as the commercial centre of the fertile and well-cultivated plain of the rioja, logrono has an important trade in wine. the district of logrono was in ancient times inhabited by the _berones_ or _verones_ of strabo and pliny, and their _varia_ is to be identified with the modern suburb of the city of logrono now known as varea of barea. logrono was named by the romans _juliobriga_ and afterwards _lucronius_. it fell into the hands of the moors in the 8th century, but was speedily retaken by the christians, and under the name of lucronius appears with frequency in medieval history. it was unsuccessfully besieged by the french in 1521, and occupied by them from 1808 to 1813. it was the birthplace of the dumb painter juan fernandez navarrete (1526-1579). logroscino (or lo groscino), nicola (1700?-1763?), italian musical composer, was born at naples and was a pupil of durante. in 1738 he collaborated with leo and others in the hasty production of _demetrio_; in the autumn of the same year he produced a comic opera _l'inganno per inganno_, the first of a long series of comic operas, the success of which won him the name of "il dio dell' opera buffa." he went to palermo, probably in 1747, as a teacher of counterpoint; as an opera composer he is last heard of in 1760, and is supposed to have died about 1763. logroscino has been credited with the invention of the concerted operatic finale, but as far as can be seen from the score of _il governatore_ and the few remaining fragments of other operas, his finales show no advance upon those of leo. as a musical humorist, however, he deserves remembrance, and may justly be classed alongside of rossini. logwood (so called from the form in which it is imported), the heart-wood of a leguminous tree, _haematoxylon campechianum_, native of central america, and grown also in the west indian islands. the tree attains a height not exceeding 40 ft., and is said to be ready for felling when about ten years old. the wood, deprived of its bark and the sap-wood, is sent into the market in the form of large blocks and billets. it is very hard and dense, and externally has a dark brownish-red colour; but it is less deeply coloured within. the best qualities come from campeachy, but it is obtained there only in small quantity. logwood is used in dyeing (q.v.), in microscopy, in the preparation of ink, and to a small extent in medicine on account of the tannic acid it contains, though it has no special medicinal value, being much inferior to kino and catechu. the wood was introduced into europe as a dyeing substance soon after the discovery of america, but from 1581 to 1662 its use in england was prohibited by legislative enactment on account of the inferior dyes which at first were produced by its employment. the colouring principle of logwood exists in the timber in the form of a glucoside, from which it is liberated as haematoxylin by fermentation. haematoxylin, c16h14o6, was isolated by m. e. chevreul in 1810. it forms a crystalline hydrate, c16h14o6 + 3h2o, which is a colourless body very sparingly soluble in cold water, but dissolving freely in hot water and in alcohol. by exposure to the air, especially in alkaline solutions, haematoxylin is rapidly oxidized into haematein, c16h12o6, with the development of a fine purple colour. this reaction of haematoxylin is exceedingly rapid and delicate, rendering that body a laboratory test for alkalis. by the action of hydrogen and sulphurous acid, haematein is easily reduced to haematoxylin. it is chemically related to brazilin, found in brazil-wood. haematoxylin and brazilin, and also their oxidation products, haematin and brazilin, have been elucidated by w. h. perkin and his pupils (see _jour. chem. soc._, 1908, 1909).