should be especially heavy, particularly the flywheel, in order that sudden changes in the load should not interfere with the proper regulation of the engine speed.

The accompanying diagram, Fig. 1, shows a typical load curve at the power-house. Curve A is that of the trains in service. Curve B shows the additional amount of energy for heating the cars, with heaters only partly turned on during the rush hours; while curve C gives the total load with heaters turned on full during the rush hours. The high peaks of the curve occur at the rush hours of travel,

The second diagram, Fig. 2, shows the violent fluctuations in the demand for electrical energy for operating the trains.

In the third-rail system the use of the ordinary track rail for the conductor was largely a matter of convenience in the first case, as rails were the easiest form of steel to obtain in reasonable lengths, and their shape was such as to lend themselves to the various requirements of attaching bonds, angle bars and insulating supports. The value of an ordinary commercial steel rail as an electric conductor, as compared with copper, is about 10 or 12 to 1, with of course the additional disadvantage against the rail of the necessity of the frequent bonding, the rails usually coming in 30-foot lengths. To offset this lower carrying capacity, however, compare rails at $17 per ton with copper at $360 per ton, and it can be seen that one can afford to put in the larger amount of steel required for a given electrical capacity and still have a good margin in favor of the rails. A commercial 80-pound track rail has a carrying capacity about equal to an 800,000 centimeter copper cable. In purchasing the contact rails for the extension of a western railway line, they were made of steel of a special chemical composition, having a higher electrical carrying capacity than the ordinary commercial steel rail. The composition was obtained after a series of experiments conducted for the Manhattan Railway in New York, with a view to getting the best possible conductor with a composition of steel that could be successfully rolled into rails. The use of this composition results in a steel rail so soft as to be unfit for ordinary railway service, but the conductivity is raised so that, compared with copper, the ratio is about 8 to 1, as against 12 to 1 for ordinary commercial steel rails.

THIRLMERE, thèrl-mer, England, a long and narrow lake in the mountains of Cumberland County, in the centre of the Lake District, northwest of Mount Helvellyn, between Derwentwater and Grasmere. It is three miles long by a quarter of a mile wide. The city of Manchester bought and converted it into a reservoir for its water supply, and the system, begun in 1886, was completed in 1894 at . enormous

expense.

THIRLWALL, therl'wâl, Connop, English prelate and historian: b. Stepney, Middlesex, 11 Jan. 1797; d. Bath, 27 July 1875. He was educated at the Charter-house and at Trinity College, Cambridge, where he obtained a Fellowship. He afterward studied for the law and was called to the bar in 1825. Having exchanged the law for the church he was ordained in 1828, and some years after received the living of Kirby Underdale, in Yorkshire. Here

he added to his pastoral duties a variety of literary labors. The first of his works, published by himself (his father had previously issued a number of essays and poems written by him in extreme youth), was a translation of Schleiermacher's Gospel of Saint Luke,' to which he prefixed an introduction. This work appeared anonymously in 1825. His next work was a translation of the first two volumes of Niebuhr's History of Rome,' with Archdeacon Hare (1828-31). Then followed the work to which he chiefly owes his reputation, his 'History of Greece, the first edition of which appeared in Lardner's Cabinet Cyclopædia,' in eight volumes, between 1835 and 1844. It was well received, and before the appearance of Grote's history (the first two volumes of which were published in 1846) was without a rival in the English language. Grote himself praises it for the learning, sagacity and candor it displays, and said that if it had appeared a few years earlier he should probably never have conceived the design of his own work. In 1840 Thirlwall was presented by Lord Melbourne to the Welsh bishopric of Saint David's, which he resigned a little more than a year before his death. He was for a time one of the editors of the Cambridge Philological Museum,' and during the closing years of his life was a member of the committee for the revision of the Old Testament. He was one of the bishops who spoke and voted for Gladstone's bill for the disestablishment of the Irish Church. Consult Perowne, 'Remains, Literary and Theological, of Connop Thirlwall' (London 187780); Thirlwall, Essays, Speeches, and Sermons' (1880); Stanley, Thirlwall's Letters to a Friend' (London 1882); Morgan, 'Four Biographical Sketches' (1892); Clark, Old Friends at Cambridge and Elsewhere' (1900).

THIRST, a craving for water or other drink. As appetite shows a need for the introduction of food into the system, so thirst is a sensation indicating the necessity of an increased supply of water. This sensation is referred to the throat, yet it is not a purely local feeling, but an index of the wants of the tissues at large, for thirst cannot be allayed unless the water swallowed reaches the stomach, is absorbed and carried into the blood. Thirst may also be relieved by the direct introduction of water into blood-vessels or by rectal injections of it, or by its absorption through the skin. How long the demands of thirst may be successfully withstood cannot be stated definitely, since human beings as well as the lower animals differ among themselves, and under varying circumstances of climate, etc., as to the degree of tolerance. Certain it is that of all substances a regular supply of water is most essential to the maintenance of life. If deprived of it for even 8 or 10 hours, greater inconvenience, pain and debility are suffered by an individual than from an equal deprivation of solid food. As thirst is but the expression of a dearth of water in the tissues, any condition which causes a more rapid elimination of water than usual will increase thirst. Such is the effect of severe muscular exercise, especially, for example, the exertion in a heated atmosphere habitual with stokers, iron-puddlers, etc. Thirst is also increased by certain articles of food, excess of salt or sugar, for example: in

febrile disorders; in severe diarrhoeas and hæmorrhages; in diabetes; in acute gastritis; in polyuria; in certain forms of hysteria, etc.

For allaying thirst nothing is so grateful as pure cool water, sipped a little at a time. Sweet drinks are not as effective in relieving thirst; but the vegetable acids in oranges, lemons, grapes, limes, etc., have a tendency to allay thirst, and to lessen the desire for large quantities of fluid, since the acid provokes an increased flow of saliva. Toast-water, small pieces of ice, effervescent drinks and dilute phosphoric acid alone or combined with a little aromatic bitter are also of value. In fever, cleansing the mouth, and swabbing it with glycerine, borax and water is of more service sometimes than drinking large quantities of water.

THIRTEENTH AMENDMENT. See CONSTITUTION OF THE UNITED STATES; CONSTITUTIONAL AMENDMENTS, HISTORY OF.

THIRTEENTH CENTURY. John Fiske in The Beginnings of New England' terms this period "The glorious thirteenth century" "a wonderful time, but after all less memorable as the culmination of mediæval empire and mediæval church than as the dawning of the new era in which we live to-day." John Morley said, "I want to know what men thought and did in the thirteenth century-because the thirteenth century is at the root of what men do in the nineteenth century." Freeman The Norman Conquest' calls it "The age of wonders

which wrought the body politic of England into a shape which left future ages nothing to do but to improve in detail." Frederick Harrison in A Survey of the Thirteenth Century' declared "Of all the epochs of effort after a new life that of the age of Aquinas, Roger Bacon, Saint Francis, Saint Louis, Giotto and Dante is the most spiritual, the most really instructive, and indeed the most truly philosophical." It would be hard to find a group of men so different in character, ways of looking at things and individual intellectuality, so concordant in their estimate of an important period of history as these expressions indicate, but similar appreciation might be quoted from Macaulay, Green, Bishop Stubbs, Carlyle, Walter Scott and many others.

The century has been hailed by many as the greatest in the history of humanity. Nothing shows more clearly the recent change in estimation of the Middle Ages than this. No phase of human achievement in the intellectual and artistic side of man is lacking in this age; many are represented by products that surpass all others. In painting and sculpture, in architecture, in the minor arts and crafts, in literature, in philosophy, in education, in social work, even in the building of hospitals and the care of the ailing, and most surprising of all in medical education and surgery, there was a wonderful accomplishment at this time, the history of which was concealed from us until comparatively recent years by an exaggeration of interest in classical antiquity and in the Renaissance. Just in proportion as we have become deeply interested once more in art, architecture, the arts and crafts, in sculpture and handsome public buildings, in the home and the city beautiful, we have learned to realize how many

of the ideals we are striving for now were accomplished marvelously in this late mediaval century. Generations which themselves had lost or impaired these higher interests, affected to condemn this old time. It was grouped among the "Dark Ages," though we now know it to have been in John Fiske's expression one of the "Bright Ages."

The central interest of the century and its greatest triumph was the Gothic cathedrals. In England and France particularly, but also in Germany and Italy there arose in the early part of the century some of the most beautiful edifices ever built by man. The generations solved the architectural engineering problems of these huge constructions with absolute success. The decoration of them made a universal appeal and for sheer beauty and suitability has never been excelled. The sculpture on the façade of many of these Gothic cathedrals as at Amiens, Chartres, Rheims, is among the greatest plastic work in the history of art. The figure of Christ over the main door at Amiens has been declared the most beautiful presentation of the human form divine ever made. Every phase of cathedral decoration took on the perfection of its sculpture. The carved stone work, the hammered iron of the gates and grilles, the very hinges and latches of the doors, the brass and bronze work in connection with the altar, the bells, the stained glass, all approached perfection so closely that they have been objects of deep admiration ever since whenever men have been profoundly interested in the arts and crafts. The stained glass has never been excelled and is still an object of almost reverential respect, some of it unapproachable in its beauty.

All the fittings and furnishings of the cathedral, even the least obtrusive, partook of the same surpassing qualities. Dark corners were not left unfinished for it was the house of God. Every detail was the object of loving devotion. The needlework of the time is probably the best in history. The cope of Ascoli (circa 1280) is looked upon as the most beautiful ever made. The church vestments and hangings were charmingly worked. The precious vessels for the altar were gems of the metal workers' art, of exquisite line and form, delicately finished and appropriately set with jewels. The Mass books, as well as the Books of Hours, used by the educated worshippers, were SO beautifully illuminated that they have been marvels ever since and command high prices in the auction-rooms. Manifestly, there was nothing that the people of the time wanted to do well which they did not accomplish with a marvelous perfection. Their domestic and municipal furnishings partook of the same excellence. The very utensils in the kitchen were beautiful as well as useful and the combination of the two qualities in ordinary life has been declared the criterion of culture in the hearts of a people.

The historic life of the century centres around the cathedrals very much as their social life centred around it in the cities and towns. Their education came into existence as the development of cathedral schools and these were usually placed under the rectorship of the chancellor of the cathedral. The studia generalia, as the universities were called

because they provided education in SO many different subjects, grew into their modern form during the courses of the century. At the beginning a few cities, Salerno, Montpelier, Bologna and Paris and one or two others, had rather important schools of special subjects around which various faculties gradually gathered. By the end of the century there were some 20 important universities in our modern sense of the word with large undergraduate departments and as a rule the three graduate departments of theology, law and medicine. The course of study for undergraduates was summed up by Huxley in his inaugural address as rector of Aberdeen University: "I doubt if the curriculum of any modern university shows so clear and generous a comprehension of what is meant by culture

as

this old trivium and quadrivium." The seven liberal arts, as the trivium and quadrivium were also called, constituted the undergraduate university studies of grammar, logic and rhetoric, geometry, astronomy, theology and

music.

All of these subjects were treated from a scientific standpoint and these were really scientific universities. The study of the classics as the basis of undergraduate education did not come in until the Renaissance time. Hence Huxley's candid admiration for these old-time universities so that he did not hesitate to say that "their work brought them face to face with all the leading aspects of the many-sided mind of man." The philosophical teaching particularly anticipated many modern ideas. Matter and form as the explanation of the composition of matter resembles the modern physical chemistry theory that all matter consists of an underlying substratum the same in everything and differentiated into various substances by the dynamic elements which enter into it. The scholastics taught that matter and force could be annihilated by the power that brought them to existence, but not destroyed by any human agency, thus anticipating the modern experimental demonstration of the indestructibility of matter and the conservation of energy. They faced the ethical problems of mankind, especially those which concern social relations, exactly in the same spirit which the modern world, after a rather long interval of failure to recognize human rights as superior to those of property, has come around to again. In writing on capital and labor for our time Pope Leo XIII quoted the ethics of Saint Thomas Aquinas, drawn up more than six centuries before.

The numbers in attendance at the universities at the end of this century were probably larger in proportion to the population of the various countries than at any time in the history of education down to our own day. The universities of Bologna and of Paris had, during the last quarter of the century, more students than any university of modern times. Oxford and Cambridge were more numerously attended than at any time afterward. Some of the students were boys of 12 or 13 but graduation was earlier than with us as it is still in most foreign countries. On the other hand many mature students remained at the university for years listening to a favorite professor or working up some special theme. The literary output of the universities in philosophy and

theology as well as from the graduate departments generally was extensive. Original work was encouraged, though it was the subject of severe criticism. Groups at various universities were engaged in encyclopedic research and publication. A series of summas of knowledge in general and of special departments was made. The discipline of the immense numbers of students represented a problem which was solved by sharing disciplinary regulation with students committees chosen by the Nations, that is, the organizations of the students from particular parts of Europe in attendance at the university. The Nations were fraternal unions which helped the student when he first came to the university to orient himself and get settled for his university work. They protected students against impositions and furnished information with regard to courses and professors. Many of the features of modern life at our universities were thus anticipatea. Initiations accompanied by hazing were common practices and the Nations provided recreation of various kinds. On the other hand when students were ailing or when remittances from home were delayed by the vicissitudes of the times, help was provided and students were tided over crises in their affairs. A number of abuses crept into university life through these organizations and conflicts between town and gown are noted before the end of the 13th century, but it was later in the history of universities that these became so intolerable as to demand correction. In the early history of the universities the students were as important a factor at least as the faculty and new universities were often founded by the withdrawal of dissatisfied students to some other town.

In

The graduate schools were the most important departments of the universities. theology, Saint Thomas of Aquin or Aquinas has been an authority ever since and the contributions which he made to philosophy_have been the subject of enduring interest. There was a magnificent development of law throughout the various countries and a corresponding evolution of the teaching of law. Canon law particularly was taught with a scientific thoroughness unequalled before and unsurpassed since. It became the basis of all European law. The medical schools are, however, the special surprise for our time. Early in the century the Emperor Frederick II made a law for the Two Sicilies requiring students of medicine to spend some three years at the university preliminary to their medical studies, and then four years at medicine, followed by a year of practice with a physician before they were allowed to practise for themselves. That is a modern standard re-established but recently after a long interreguum. Salerno, the first university medical school, set the example in teaching and insisted on the employment of the natural means of cure, fresh air, water, diet, exercise and occupation and diversion of mind. These are all emphasized in the famous Regimen Sanitatis Salernitanum, issued at Salerno about the beginning of the century and published in some 300 editions since the invention of printing. It was the most read popular book on medicine for centuries, republished many times even in the last century. The textbooks in surgery extant from this time have been a revelation. The surgery of the four masters of Salerno

who collaborated in the work quite after the modern fashion of textbook writing is surprising in its anticipation of modern surgery. We have, besides, the book of Theodoric of Lucca and of Bruno of Longoburgo as well as of William of Salicet, Lanfranc and Mondeville. In these, anæsthesia, through mandrake and opium, antisepsis by the use of strong wine-— they boasted of union by first intention- and a great many of the operations, especially a whole series of intra-abdominal and intracranial operations, as well as many instruments and modes of treatment considered to be modern are described. In the large, very wellplanned hospitals of the time, with finely organized nursing, many operations undreamt of in the intervening centuries until our generation were successfully accomplished, not merely as emergency interventions, but to save suffering and prolong life.

In

The names of the teachers in these graduate schools, Albertus Magnus, Thomas Aquinas, Roger Bacon, Bonaventure, Duns Scotus and Alexander of Hales, are probably better known than any group of teachers in history. stead of losing prestige in the course of time they have gained repute in recent years with increase of interest in the. medieval period. Albertus Magnus is the only scholar in history with whose name the adjective great has become incorporated as if it were a family name. He was a man of the widest interests, intent on testing all knowledge carefully. Humboldt pointed out how much he knew about physical geography, physics, climatology and the physiology of plants. Meyer the historian of botany declared "No botanist who lived before Albertus could be compared with him unless Theophrastus with whom he was not acquainted, and after him none has studied plants so profoundly until the time of Conrad Gesner and Cæsalpino." Albert discussed scientifically the Milky Way and its significance, the irregularities in the moon's surface, lunar rainbows, various kinds of refraction and many other problems supposed to be modern. His great pupil Aquinas, adopting Aristotle, laid down the metaphysical principles which are now coming to be recognized as fundamental ideas in the physical and social sciences. Hence a great revival of study of his works. Even more immediately interesting than these to the modern world is Roger Bacon, the international celebration of whose 700th birthday attracted so much attention at Oxford in June 1914. Bacon probably invented gunpowder, suggested that explosives might be used for motor purposes,- boats running without oars or sails and carriages without horses,- discussed he theory of lenses, declared that mathematics and experiment were the two important factors for advance in science; anticipated modern ideas as to Biblical revision, insisted on the value of Greek and Hebrew for education, declared that light travels with appreciable velocity and spoke with assurance of aviation. It is clearer than ever now why the people of his time called him Doctor Admirabilis, the admirable teacher.

A feature of 13th century education most interesting for our time is the feminine education of the period. At Salerno in southern Italy women were encouraged to study even medicine during the 12th century and the department of

women's diseases was in their charge. We have many licenses to practise medicine in the Two Siciles granted to women at that time still extant. At Bologna at the end of the 12th century the daughter of Irnerius the great teacher of law became an instructor in the law school. All of the Italian universities had women teachers on their staff. The unfortunate Héloïse and Abelard incident at Paris seems to have given a serious setback to feminine education in the universities of the west of Europe, but in Italy the custom established in the 13th continued, and there have been women professors at the Italian universities every century since.

The literature of the century is the proof of the intellectual quality of the time, for it was not only great but widely read. Its value will be best recognized from the fact that probably well-read people know the works of the 13th century better than of any other, except their own, though they are often not quite conscious of the fact, not having noted the dates. The enduring work of the time begins with the Arthur legends put into fine literary form by Walter Map or Mapes, just as the century begins.. To him we owe Lancelot. "Like Paris, handsome, and like Hector, brave," but with a fault that makes him even more appealing, so that probably he is the most interesting character of fiction ever created. Then came the ballads of the Cid in Spain, followed by the Nibelungenlied with the Meistersingers and Minnesingers and then the Troubadours and Trouvêres with the Romance of the Rose and Renard the Fox in what we call France, and, finally, the Trovatori in Italy, culminating in Dante who, the greatest of the Trovatori, was just ready to write what has often been proclaimed the greatest poem of all literature, as the century closed. Such other writers as Villehardouin, Joinville, Matthew of Paris, the earliest encyclopedists, Vincent of Beauvais, Thomas of Cantimprato, Bartholomew the Englishman, and such works as that of William of Durandus and Jacobus de Voragine of the Golden Legend, are perennially interesting. The century has also the greatest of the Latin hymns, the 'Dies Iræ, the Stabat Mater,' the marvelously beautiful religious poetry of Saint Francis himself, of Saint Thomas Aquinas, of Bernard of Morlaix and of Saint Bonaventure.

The century saw the publication of what must be considered the first of encyclopedias. Vincent of Beauvais, under the patronage of Louis IX, with the aid of a great many young assistants of the Dominican Order whose expenses were generously defrayed by the king, was enabled to gather an immense amount of information for his time. In spite of the difficulty of hand transcription, his work extends to over 50 of our volumes octavo. The matter is well chosen and of wide interest, and the surprise is how many things supposed to be much more modern in human knowledge are to be found in Vincent. Pagel declared "the reading of the work easily becomes absorbing.

The century provided a magnificent series of contributions by explorers to the knowledge of the world at that time. Travelers in the Near and the Far East told the stories of how other people lived and their books still extant demon

strate what excellent observers they were. The greatest of these explorers was Marco Polo, whose name was for so long a by-word for credulity and tendency to exaggeration, who proves now, like Herodotus, to have had a basis of real truth for all that he told. He visited the Christian kingdom of Abyssinia as well as China and nearly all the world between. He told of Burmah, of Siam, of Cochin China, of Japan, of Java, of Ceylon and India and he had heard interesting accounts of the coast of Zanzibar and distant Madagascar and at the opposite end of the world of Siberia and the shores of the Arctic Ocean. Colonel Yule, a modern authority on the literature of travel, can scarcely find words to praise Polo enough. There were many other famous travelers whose works have come down to us from the century and are republished in recent years. Friar John of Carpini went on a mission to the Tatar emperor of the time, across the Ural Mountains and River, past the northern part of the Caspian Sea, across the Jaxartes, along the Dzungarian lakes to the Imperial camp near the Orkhon River. Friar William of Rubruk or Rubruquis, the account of whose travels was printed by Hakluyt in his collection of voyages at the end of the 16th century, went even further. Some of his observations, as for instance on Chinese writing, are surprising enough, but he has many details of Asiatic nature, ethnography, manners, morals, commercial customs, that were true to life. Friar Oderic a little later traveled through India and then through China to Nankin and Peking, reached the Great Wall, entered Tibet and appears to have visited Lhasa. Sir John Mandeville (15th century) borrowed much from him, as well as from the Præmonstratensian monk Hayton. Most of the men who thus wandered in distant lands were graduates of the universities of the time and while they were credulous with regard to what they heard, very much as Herodotus himself, they could be absolutely depended on for information with regard to things which they themselves had seen.

Besides the intellectual education which came in the cathedral schools and their developments at the universities there was a great phase of popular education along artistic lines which was initiated in the midst of the building of the cathedrals. Most of the beautiful things in the great Gothic churches were made by workmen of the little mediæval towns in which they were built. None of these had more than a few thousand and probably did not average 10,000 inhabitants. Somehow artistic artisans to do all the beautiful work demanded were found and there was the popular taste to appreciate and the diffusion of liberal education to patronize and encourage the making of such beautiful things. There are receipted bills for the payment to village blacksmiths and village carpenters, for iron and woodwork, which we now rank as artistic masterpieces. Practically all the decorations and fittings of their cathedrals were executed by the townsmen themselves and even their bells and stained glass were made at home, not brought from a distance. Transportation difficulties threw them back on themselves and compelled technical developments while transportation facilities in our time have had an VOL. 26-36

opposite effect. To secure the making of such beautiful things there had to be a skilled and well-trained group of artisans. There has probably never been a time when the arts and crafts, in our modern sense of that term, have been so appreciated and cultivated. In this culture the working classes were probably the most important factor. Technical training was provided by the guilds. Boys were apprenticed to trades and crafts of various kinds, and after four or five years of training became journeymen and traveled from place to place to learn the secrets and customs of their craft in the various regions. After two or three years of this on the presentation and acceptance of an example of their work called a masterpiece-this is where this old English word comes from-they were admitted as master workmen into the guild. This represented a degree in technics. The guild training was practically a technical school and as the guilds existed everywhere opportunities for arts and crafts education abounded. Any growing youth who had taste or talent for any form of artistic work could easily secure the opportunity for its development and then, more important still, obtain the chance to do his work in conditions where encouragement and appreciation would come to him. In England at the end of the Middle Ages there were 30,000 guilds (Toulmin Smith), the county of Norfolk alone having 900, the small town of Wymondham having 11 still known by name. One of them possessed a guild hall. All the guilds of the town are said to have been "well endowed with lands and tenements." In Bury Saint Edmunds, Suffolk, there were 23 guilds; Boston, Lincolnshire, had 14 of which the titles and particulars are known and London had a large number. The guild had increased in number greatly from the 13th century but there is definite evidence that most of the important guilds in existence in England at the end of the 15th century had been in existence for several hundred years. During this time they had accumulated very large amounts of money and invested funds of various kinds, not so much from the fees paid by their members as from bequests of various kinds made to them because it was felt that they were doing great good work. Unfortunately it was this accumulation of money that led to their legal destruction, though a few of the London guilds which were spared in the time of Henry VIII on the plea that they were trading or secular associations and not religious organizations have at the present time an income of over $50,000 per year each. The old guilds were trades unions, social clubs, insurance societies, civic organizations, popular entertainment committees, but withal religious sodalities enforcing fulfilment of religious duties yet not permitting the clergy to hold office or dominate policy.

The social history of the time is its most interesting feature for our era. The beginning of the period saw the rise of the two great mendicant orders, the Begging Friars, the Franciscans and Dominicans. A world so deeply intent on commerce as to give rise to Hansa and the great Italian commercial cities was afforded the example of two large bodies of men who took voluntary poverty for their lot so as to be free to do better things in life.