MAGNETISM.

were acted on by the latter. This phenomenon was formerly attributed to the existence of minute quantities of iron or iron compounds in those different bodies, but this is now known to be a mistake. Faraday, in 1845, showed that nearly all substances, even gases, have properties in relation to magnetism; and as regards the phenomena which they exhibit, they are divided into two bodies, paramagnetics and diamagnetics. To the former class belong iron, nickel, cobalt; also, in a less degree, manganese, chromium, cerium, oxygen gas, and platinum. To the latter, bismuth, phosphorus, antimony, and copper; also, in a less degree, zinc, mercury, water, lead, silver, gold, alcohol, ether, hydrogen gas, air, blood, sulphur, and arsenic. The term magnetic is often used as synonymous with paramagnetic.

The distinction between the two classes is. that a needle or bar of paramagnetic material, when suspended freely between the two poles of an electro-magnet, takes an axial position, that is to say, disposes itself in a straight line, joining the two poles; whereas a bar of diamagnetic material takes an equatorial position, that is, a position at right angles to the joining line. Again, a body of the former kind, if brought nearer to one pole than the other, is attracted; while a body of the latter class is, in similar circumstances, repelled. The magnetic properties of crystals depend upon their form as well as upon their material, uniaxial crystals having a tendency to place their optical axes in an axial or in an equatorial position, according as the crystals themselves are (in the geometrical sense) positive or negative.

Just as in electricity, the electric force (whatever it may be) is induced on an uncharged body by the presence of an electrical charge, so can the magnetic force be induced on a piece of soft iron by the presence of a magnet. If iron filings be strewn on a piece of soft iron and a magnet brought near, it will at once become magnetic and attract the filings. But even more, the earth's magnetism may be used for the purpose of induction.

If we place a bar of soft iron, suspended by a collection of silk strings at its middle, in a direction parallel to the magnetic axis of the dipping-needle, the action of terrestrial magnetism will have full effect on the bar, its natural magnetisms will be decomposed, and it will acquire a polarity similar to that of the needle, its poles repelling the similar poles of the needle and attracting the contrary poles. Even a poker or such object held at the proper declination and dip, and smartly tapped once or twice, will acquire temporary magnetic purposes. If the bar be left for a long time in the direction of the magnetic axis, so as to acquire some oxygenation, or if it be heated to a red heat and suddenly cooled by immersion in water, it will acquire a coercive force, and become permanently magnetic. Iron crosses, weathercocks, &c., which have been long kept in a fixed position, or have been struck by lightning, acquire magnetic properties in the manner above described.

It now becomes clear why a magnet attracts ironnamely, it converts it into a magnet, and then attracts it along certain directions in relation to its new poles, which are called LINES OF FORCE.

The methods of producing a magnet by induction and by contact have been given in the article MAGNET. It remains to notice magnetization by heat and by electricity. If a bar of steel be heated to redness, and cooled while lying in the magnetic meridian of the earth, it becomes magnetically polar. (By magnetic meridian is meant a plane drawn through the zenith and through the magnetic north and south poles of the earth, as determined at that place by a horizontally balanced magnetic needle. The angle between such a meridian and the meridian of longitude is the DECLINATION of the place; see that article). No such property is acquired if it cools while lying east and Carré produced strong magnets by casting iron in moulds lying in the magnetic meridian and in an intense

west.

MAGNETISM.

iron bar it remains a magnet only so long as the electric current continues. This remarkable property of electromagnetism is explained in the article ELECTRIC LIGHTING. force it exerts, and the unit of magnetic strength is thus The strength of a magnet is measured by the magnetic given-" A unit magnetic pole is one of such strength that, when placed at the distance of 1 centimetre from a similar pole of equal strength, it repels it with a force of one dyne." The lifting power of a magnet is not the same as its strength. A horseshoe magnet of the form shown in fig. 2 (in which Fig. 2.

Here a is a constant depending on the goodness of the steel and the method of magnetizing it. In the best steel magnets a is between 19 and 23.

Magnetization is found very largely to reside upon the surface of a magnet. Frequently if the outside of a har is eaten away by acid the magnetization is destroyed. But a thoroughly magnetized bar usually exhibits some force within also.

Theory of Magnetism.-The following facts are relied upon by many physicists as warranting a theory of magnetism. A steel bar becomes slightly longer when magnetized than it was before; Joule found it increased by one 720,000th part. A little clink is heard at the moment of magnetization or demagnetization. A tube containing water with iron dust thickly mixed becomes consideraby less opaque when magnetized. A twisted iron wire tends to untwist itself. A piece of iron rapidly magnetized and

MAGNETISM.

demagnetized several times grows hot as if suffering friction. On these facts it is considered possible that the molecular result of magnetization is to set the molecules of bodies on end, the long axes pointing in the direction of the bar from pole to pole. Further it is held that the luminiferous ether is capable of such molecular alteration, and it is ertain that a ray of polarized light passing through a strong magnetic field has the direction of its vibrations changed-its plane of polarization is rotated. On this theory the production of a magnet by cooling heated iron ying along the magnetic meridian, and the destruction by bating it to redness or by roughly using it, are readily made intelligible. Besides, since every part of a magnet is a magnet, and since all magnets tend to turn north and wath, it seems highly probable that all the molecules of a at are polarized-i.e. set one way.

Laws of Magnetic Force.-These are two: 1. Like xas are mutually repulsive, unlike poles attractive; 2. the force exerted between two magnetic poles is proportical to the product of their strengths, and inversely proportional to the square of the distance between them. Or to use a formula

mx m' f= d'

were fis the force in dynes, m and m' the strengths of the pies, and d their distance asunder.

The articles DECLINATION, INCLINATION, ISOGONIC mi IsoCLINIC lines give all necessary particulars as to the variations in the magnetism of the earth and the consequent variations in the behaviour of the magnetic needle. Ite connection between magnetism and electricity was Cistered quite at the beginning of the century (1802) by Bmagnosi of Trent; but it was not till 1819 that anything te was known about it. At this date Oerstedt of Cetagen found that a magnet tends to set itself at nat angles to a current of electricity, and that it turns to the right or the left according to the direction of the currest. Thus, above and along a magnetic needle mounted a pivot, hold a wire conveying a current of electricity. Drely contact is made the needle is deflected. If now the wire be held in the same direction, but below the red, the latter is deflected exactly in the reverse way. Ar pere's rule is exceedingly ingenious. Suppose a man to be swimming along the electric current, his face directed wards the needle (whether that be above or below him), the deflection of the north-seeking pole will always > towards his left hand as it starts from rest. Thus, f 3 the arrows show the direction of the current of electricity from p to n; Ampère's electric swimmer Fig. 3.

MAGNETITE.

Looking in the direcround the wire is in the

action on the field around it. tion of the current the "set direction of the hands of a watch, as in the figure. If such a wire pass vertically through a sheet of card carrying a heap of iron filings, directly contact is made and the card tapped smartly, the filings will set themselves concentrically in rings round the axis formed by the wire.

Magnetic force, just as electric force, is expressed in terms of potential." It is usual to consider that the magnetic potential at any point is the work that must be spent on a north-seeking unit magnetic pole in bringing it up to that point from an infinite distance, and the potential due to several poles if there are such, is the sum of their separate potentials. The potentials due to southseeking poles are considered as negative quantities, and bear the minus sign. The difference of magnetic potential between two points is the work to be done on or by a unit north-seeking magnetic pole in moving from one point to the other. Equipotential surfaces are those imaginary shells or surfaces surrounding a pole, over which the potential is equal, and magnetic force always acts across these surfaces, perpendicular to them. As the lines of force deviate by radiation the space round a magnet may be considered as divided up into tubes of force, any section across which will give a constant quantity of lines of force.

Magnetic force is the range of change of magnetic potential per unit of length. Magnetic density is the amount of free magnetism per unit of surface. Magnetic intensity (of field) is measured by the force with which it acts upon a unit magnetic pole, unit intensity being one dyne on a unit pole. There is therefore a field of unit intensity at a centimetre distant from a unit pole. We may express the same things in a tabular form. Strength of mag. pole

m =

force X sq. of distance. strength. strength.

=

work

force

It must be added, in conclusion, that while it is admitted that electricity produces magnetism the converse is equally true. For let a magnet be moved into a coil of wire connected with a galvanometer, a momentary current is Withdraw the magnet perceived to flow, then to cease. sharply, and a momentary current flows in the reverse direction, and ceases. The latter current is a direct current-i.e. in the direction of such an electric current as would magnetize a piece of iron with the same polarity as the magnet now possesses.

MAGNETISM, ANIMAL. See HYPNOTISM, MES

MERISM.

MAGNETITE is the richest ore of iron, containing about 72 per cent. of the metal. It is composed of the so-called magnetic oxide iron (Fe3O4), or, as some regard it, is a mixture of the protoxide and sesquioxide of iron (FeO,FeO3). It has a specific gravity of about 5, and hardness of about 6. It crystallizes in the cubic system, the most common form being a regular octahedron, but rhombic deodecahedra also occur. The colour is black and the mineral is brittle; it is highly magnetic, and often exhibits polarity.

This mineral either derives its name from Magnesia, a province in Lydia, or, according to Pliny, from one Magnes, who observed it adhering to the iron of his shoes. When polaric, it is called lodestone, and from it the terms magnet and magnetism are derived.

On the dis

Magnetite occurs widely disseminated as small crystals in many eruptive rocks, also in some metamorphic rocks and fine-grained slates and chlorite schist. integration and denudation of these rocks it forms a large proportion of the black sand found in many rivers, and along the sea-coast in some places. It also occurs in lodes and large masses, mostly in crystalline or highly metamor

MAGNETO-ELECTRICITY.

phic rocks, one of the most remarkable deposits being that of Dannemora, in Sweden; but it is also found abundantly in Norway, Russia, and many other European localities, as well as in large beds in the United States of America and in Canada. In the British Isles it does not occur in sufficiently large masses to be of commercial importance. From the high percentage of the metal which magnetite contains, and the general absence of impurity in it

Crystals of Magnetite or Magnetic Iron. especially the more injurious, as sulphur and phosphorus -it is one of the most valuable ores of iron, and from it much of the purest iron of commerce is obtained, notably the Swedish iron. The famed Damascus steel was also obtained from magnetite.

| perish utterly we should still see it shining for that time after it had vanished from creation. Sirius is held to be 324 times as bright as a star of the sixth magnitude; other stars of the first magnitude vary down to Pollux, which is 100 times as bright as the sixth magnitude. The second magnitude is on the average twenty-five times as bright as the sixth, the third is twelve times, the fourth is six times, the fifth twice as brilliant as the sixth. If, as on the whole seems by far the most probable, nearness and not size is the explanation of astronomical magnitude, then we should consider, basing our calculations upon the known distances of those few stars which can be measured (Sirius, Alpha Centauri, &c.), that light requires on the average fifteen and a half years to reach us from a star of the first magnitude, twenty-eight years from one of the second, forty-three years from one of the third, and so on, till for stars of the twelfth magnitude no less than 3500 years would be required for light to reach us, since they would seem likely to be at least 1000 times as far off as Alpha Centauri and Sirius.

MAGNOLIA, a genus of plants, the type of the order MAGNOLIACEE. The species of Magnolia are trees or shrubs, all natives of North America and Asia. Magnolia grandiflora (large-flowered magnolia, or laurel bay) is an evergreen tree, reaching sometimes a height of 70 feet. It is one of the tallest and handsomest trees of North America. It has large pale green shining leaves, nearly 10 inches long, with large white flowers. It has been cultivated in England since 1737, and in this country attains a height of from 20 to 30 feet. Magnolia glauca (deciduous swamp magnolia) is a native of North America, in low, moist, swampy ground at a little distance from the sea, from

MAGNI ROSTRES is a suborder of the great order of birds, PASSERES, distinguished by having the bill large, long, and conical, sometimes slightly notched. This division includes the Chatterers (Ampelidae), Orioles (Oriolidae), Starlings (Sturnida), Crows (Corvida), and the Birds of Paradise (Paradiseida). None of this group possess any powers of song, but some among the crows and starlings are mimics.

MAGNITUDE, in astronomy. is a curiously chosen term to express the relative brilliance of stars. It rests on the quite unwarranted assumption that the brighter star is the larger; whereas it is quite as likely that its brightness is the effect of proximity as of size. The most brilliant stars are said to be of "the first magnitude," the next brilliant class are of "the second magnitude," and so on down to the fourteenth or higher numbers; 20,000,000 stars of the first fourteen magnitudes are visible in a powerful telescope, though only 6000 (3000 in each hemisphere) are visible to the naked eye, for it can only see stars down to the sixth magnitude. Of the 20,000,000 just mentioned, nearly 18,000,000 lie in or near the Milky Way, a fact of great significance. The twenty brightest stars, or stars of the first magnitude, are as follows (they may be found in our Plates CONSTELLATIONS):-Sirius (Canis Major), Canopus (Argo), Alpha Centauri (Centaur), Arcturus (Bootes), Rigel and Betelgeux (Orion), Capella (Auriga), Vega (Lyra), Procyon (Canis Minor), Achernar (Eridanus), Aldebaran (Taurus), Beta Centauri (Centaurus), Alpha and Beta Crucis (Crux), Antares (Scorpio), Altair (Aquila), Spica (Virgo), Fomalhaut (Piscis Australis), Regulus (Leo), and Pollux (Gemini), but not Castor, which is of second magnitude. These are given in the order of brightness. As far as can be guessed at present, the bright southern hemisphere star, Alpha Centauri, is the nearest of them, and it is now computed to be 20 billions of miles off, so that its light, though so brilliant, has probably taken three and a quarter years to reach us, although it travels 185,000 miles a second; and were it to

a bitter and aromatic odour resembling sassafras. On this account it has been used in America as a substitute for other aromatic bitter barks, as Cascarilla, Canella, &c., and, it is said, with great success. Although not much used in Europe, very favourable reports of its efficacy in chronic rheumatism, ague, and remittent fever have been given. The flowers are of a cream colour and have a sweet scent, which Kalm says may be smelt at a distance of 3 miles. Magnolia tripetala is a native of North America, in the Carolinas, Georgia, Virginia, and New York. The wood is soft and spongy. Magnolia acuminata is a native of North America, from Pennsylvania to the Carolinas. The fruit is about 3 inches long, and resembles a small cucumber, whence in America it is called Cucumber-tree. A tincture is made of the fruit, and is used in cases of rheumatism. Magnolia conspicua grows in China, where it has been cultivated since the year 627. Its native name is Yulan. It is a very showy tree, having white flowers, sometimes diffused with purple, which give out a most delicious perfume. Magnolia purpurea (the purpleflowered magnolia) is a native of Japan, and seldom attains a greater height than 8 feet. The bark when bruised has an aromatic odour. The flowers are mere or less purple without, and always white within. It is a very ornamental species, and worthy of cultivation. The best situation for it is against a wall, when its branches will reach a height of from 15 to 20 feet. Magnolia Campbellii is a native of Sikkim, where it was found by Hooker and Thomson. It is described as the most superb of the genus, attaining a height of 150 feet, with large rose-coloured flowers. which appear before the leaves.

MAGNOLIA CEA, an important order of plants, be longing to the POLYPETALA (series Ranales). The species consist of bushes and trees, inhabiting the temperate parts of both the Old and New World. In England, where they are exotics, they are among the most highly valued of ornamental plants, and every species which can bear the climate, or which will thrive in conservatories, has been collected with great care.

MAGON.

The genera Talanma and Magnolia have the singular property of dropping their seeds out of the back of the seed-vessels when ripe, allowing them to hang down, each saste.ded by a long extensible elastic cord, composed of decate spiral vessels.

This order of plants may be known from their allies by the sepals and petals-they are hypogynous, deciduous, phricate, in three or several series, which are not very tinct; the stamens are numerous; the carpels in a *ge series, or several on a torus, generally quite Gxtinct: the seeds without an aril (which serves to &stguish them from Dilleniaceae), and the albumen -t raminated (as in Anonacea); the embryo is minute. In the tribe Magnolie there are large stipules covering the leaves in the bud.

MA GON or MA'GO, a favourite Carthaginian name. The earliest Magon was the father of the great Hasdrubal, and was the first to bring the mercenary armies of Carthage at eficiency (550 to 500 B.C.) Another famous commander bed the chief command in Sicily from 396 to 383, and other in 344. One of Hannibal's brothers bore this are also, accompanied him to Italy, and carried the news f Caine to Carthage. Instead of sending Hannibal sucthe Carthaginians, probably through jealousy, despatched Magon to Spain, where, after Hasdrubal had left te Ceavour to join Hannibal by land, Magon held chief tommand. Here he suffered decisive defeat at the hands of the Elder Scipio in 206 B.C., and retired to Minorca, were the town he nourished into prosperity still bears a name as Port Mahon. In a last attempt to reach Haal, Magón landed near Genoa, but was badly add and defeated by Varus when he advanced, 203 He re-embarked the remains of his army to return ↑ Arxa, but he himself died of his wound on the voyage. A Cartaginian writer on agriculture of this name was very yeste ned at Rome.

MAG OT. See BARBARY APE.

MAG PIE (Fica caudata) is a well-known English Fr belonging to the crow family (Corvida). The magIr pie (the first syllable being an abbreviated form of Maige or Margaret) is widely distributed in the northern parts of both hemispheres. It is remarkable that it did at exist in Ireland some 200 years ago; and from a letter Swift to Stella it appears that in 1711, though it had ated for some time in Wexford, it was only then spreadinto the rest of Ireland. This bird is so well known at any description is scarcely necessary. The general age is pied with black and white, and the tail is long dusted, beautifully iridescent with blue, purple, The bill is strong, compressed laterally, by arched, and hooked at the tip. The wings are and rounded. The male measures 18 inches; the Te is sinaller. Scarcely anything in the way of food es ariss to the magpie; in its general habits it is aziy predaceous, destroying young poultry, game, and - all animals, and even occasionally attacking young and sickly sheep in the same way as the larger willst, when these delicacies cannot be got, it will y itself with carrion, worms, and insects, and even *** trait and grain. Hence its fondness for the vicinity Can Labitations is by no means reciprocated by the ats of the latter; and in this country, at all events, *** get to sɔ determined a persecution, that, as Mr. 1 cserves, but for its sagacity, eminently evinced *** -preservation, it would be a rare bird." It is far *** atraca in wooded districts than it used to be, and exte shyer and more suspicious of man. Dearie usually dwells in woods and plantations, t bills its nest in a high tree, but sometimes its tall hedges, and builds in a thick bush. The

spots of ash colour and brown. If taken young, the magpie is easily tamed, when, like the other species of this family, he becomes very amusing, and exhibits great power of imitating sounds of all kinds. He is, however, the most thievish of all the crows, picking up and concealing any bright object that may fall in his way, although, of course, his hoards of this nature cannot be of the slightest use to him. Various other species of the genus Pica are known. The American Magpie (Pica hudsonica) is now considered by the best authorities identical with the European magpie.

MAG PIE MOTH (Abraxas grossulariata) is a wellknown British moth belonging to the family Geometrida (LOOPERS) and the subfamily Zereninæ. The common name is derived from the magpie-like character of the markings, which vary considerably. The ground colour of the wings is generally white with black patches, which vary in number and intensity of the colour. There is an orange stripe across the middle of the fore wings, and a patch of the same colour at their base. The body is yellow with black spots. The expanse of the wings measures about an inch and a half. The caterpillar is found on the currant and gooseberry bushes, and is very destructive. Its body is cream-coloured with black rings and spots. The caterpillar of an allied species, the Clouded Magpie Moth (Abraxas ulmata), feeds on the elm. MAGYARS, the ruling caste or race in HUNGARY, are believed to be a people of Turanian origin, who fought their way to the central basin of the Danube, thence extending their conquests from the Carpathian Mountains to Servia, and from the Transylvanian Alps to the Styrian Alps. This inroad is said to have taken place in 889 A.D. They founded a powerful state, governed at first by chiefs of the house of Arpad, and then by kings of the same line. The first of the latter, commonly called St. Stephen, from the renunciation of heathenism by the nation in his reign, received investiture from the Pope, Sylvester II., in the year 1000, with a crown sent for the purpose, which is still extant. The male line of the Arpads failed in 1301, and was followed by sovereigns of different foreign families till 1526, when, by free election, the Austrian house was placed upon the throne. But the Turks invaded and held possession of the greater part of the country for upwards of a century. The Austrian princes became kings of Hungary, subject to certain stipulations ratified by treaty, the violation of which led in 1848 to a gallant but illfated struggle for national independence.

The Magyars retain their national language, which belongs to the great Finnic linguistic family, subject to slight modifications owing to long-continued contact with other forms of speech. Its vowels are resolved into two classes, one of which, a, o, u, denotes the masculine, and the other, e, i, o, u, the feminine. The words are so formed that a masculine and feminine vowel never meet in the same vocable, whether simple or compound. Another peculiarity is that the Christian name is always mentioned last, as Hunyady János, instead of John Hunyady.

According to the census of 1881, out of 15,520,710 inhabitants of the kingdom of Hungary, 6,165,088 were Magyars-that is, according to the official reckoning. But of these it is believed that fully 1,000,000 were not true Magyars. As a race the Magyars are described as dignified, courteous, and hospitable, but proud, and under the name of patriotism intolerant, and in former times extremely cruel to the subject races. The native dress, so famous for its picturesqueness, though too surely disappear

MAHABHARATA.

ing with civilization, is not extinct even in the capital, where it bursts forth in political crises, causing the streets of Pesth to look for the time being like a series of scenes from an opera.

MAHABHARATA. See INDIA.

MAH'DI, a name given by Mohammedans to a prophet who is expected to appear before the end of the world, to exalt and purify Islam and to turn the world to Mohammedanism. The expectation of such a deliverer seems to have arisen at a very early period in the history of Islam, and to have been caused, in the first instance, by the disputes which arose concerning the succession to the caliphate. A belief in a hidden, concealed Mahdi or Imaum, who was destined to be subsequently made manifest, formed an essential feature in the teaching of the Persian Abdallah, the founder of the sect of the Ismailians, who flourished, in the second century of the Mohammedan era, and since that time the doctrine has been the subject of many modifications and developments in the Mussulman world. There has always been among Mohammedan theologians a great diversity of opinion as to who the hidden Imaun or Mahdi really is, and a still greater amount of uncertainty has always existed as to the date of his reappearance on earth. In the early times of the caliphate the doctrines were evidently invented by conspirators and pretenders for the purpose of gaining the adherence of the ignorant masses, and were modified to suit the exigencies of the moment. The original idea was probably taken from the Jews, who have never lost their hope of a coming Messiah, but the Hebrew conception was transformed by the mysticism of Persia, and at later periods affected by the Christian doctrines of the second advent and of the millennium. Originally a Persian or Shiah doctrine [see IMAUM] it soon spread to the Moslems of other nationalities and denominations, and consequently Mahdis have at different periods appeared in nearly every part of the Mussulman world. Of these perhaps the most celebrated was the veiled prophet of Mokanna, best known to English readers by Moore's poem, whose death took place in the 162nd or 163rd year of the Hegira. In Turkish history there have been several, but none of them obtained much popular support, and they were all arrested and executed without difficulty. The Turks, being naturally realistic and little disposed to religious mysticism, do not readily adopt an idea of this kind, and their traditional devotion to the dynasty of Osman makes them look with suspicion on all sorts of pretenders; but the Persians, Arabs, Berbers, and negro population are more easily led, and from their dislike of the Turks are more ready to accept any one who offers deliverance from the evils which oppress true believers generally. This is especially the case with the Arabs, who regard the Turks as barbarians, and who would willingly free themselves from Turkish domination. In all ages it has been assumed that the Mahdi would have both a political and religious mission-that he would be at once a political deliverer and a religious reformer. During the existence of the caliphate as a great empire the tyrants who were to be overthrown were the Omayad and Abbaside dynasties, and the deliverer was to be of the disinherited family of Ali, but these original conceptions have in the course of time been considerably modified by external conditions. There are no longer Omayads and Abbasides, but there are still tyrants in Islam, and Islam as a whole is now threatened by an aggressive Christendom, so that the modern idea of a Mahdi is that of a divinely inspired prophet, whose mission it is to free Islam from external enemies and re-establish purity of faith and practice.

Among modern claimants to the office of Mahdi the most celebrated is Mohammed Ahmed, whose exploits in the Soudan in the years 1881-85 gave the Egyptian and British governments so much trouble. Very little trustworthy information has been published up to the present concern

MAHDI.

ing the life and teaching of this remarkable man, most of the accounts issued being evidently based upon vague native rumours or else the result of fertile imaginations. According to the story of Mousa Penez, a Frenchman born in the Soudan, and who was acquainted with the Mahdi during the early period of his career, Mohammed Ahmed was born at Dongola in 1843 of respectable parents. From his boyhood he was remarkable for religious fervour, and before he was twelve years old he had committed the Koran to memory. His two elder brothers, who were boatbuilders on the White Nile, had him well educated in Mohammedan theology and history, and for this purpose sent him to Khartoum to study under some celebrated professors there. After completing his education he devoted himself to a life of asceticism, gaining a great reputation for holiness by his practices of fasting and meditation. For a long time he remained in seclusion, but when certain of the tribes of the Soudanese, driven to desperation by the cruelty and oppression of the Egyptian governors, had resolved upon revolt, they sent to him for counsel and the aid of his presence. Upon receiving this summons be declared himself Mahdi, and being acknowledged by the Baggaras tribe his disciples began preaching all over the Soudan the advent of the prophet, and the coming extermination of the hated Turks. To strengthen his influence he took to himself numerous wives (thirty-nine, according to some accounts) from the families of the most powerfal chieftains of the country, keeping within the letter of the Mohammedan law, which only allows four, by a system of temporary divorce. The whole of the Soudan was ripe for revolt, and in a very short time he found himself at the head of several enthusiastic and warlike tribes of Arabs. To them he declared his mission to restore and purify Islam, and he at once began to insist upon the strict observance of all the precepts of Mohammedan law, and to enforce the prescribed devotional exercises with considerable rigour. He commanded his followers to abstain, not only from wine and spirituous liquors, but also from coffee and tobacco, forbade all luxury and effeminacy, announced himself to be the champion of the poor, and declared his intention of introducing a kind of socialistic equality among all true believers. It is said that when he captured El Obeid he issued an edict forbidding his followers to live in houses, and after the Bedouins had wrecked the houses of the inhabitants, the whole population were obliged to construct huts of straw in the courtyards of their dwellings, and either live in them or at least keep up the appearance of doing so. He promised relief from all the oppressive exactions of the Egyptian governors, but demanded a small tax from his followers for the support of the fighting men, and arranged to secure a due proportion of the plunder taken for the same purpose. At the outset of his career he was patronized by soine powerful slave-merchants for their own purposes, but he soon grew too strong to need their patronage, and by his skilful management gained the enthusiastic support of his followers.

An account of his victories over the Egyptian forces has already been given in the article on EGYPT. In the beginning of 1885 the town of Khartoum, which had been bravely defended by General Gordon for about twelve months, fell by internal treachery into the hands of the Mahdi, Gordon being killed in the assault; but soon after this event a rival Mahdi appeared, and Mohammed Ahmed was compelled to turn back from his triumphant advance towards Egypt, in order to attempt to regain his ascendency over the tribes who had revolted against him under their new leader. In the unhesitating faith and fanatic valour of the followers of the Mahdi we have a modern illustration of the spirit which in the early days of Mohammedanism carried the Arabs on their victorious career. Even now, although civilization is no longer endangered, should a revolt such as this spread to Arabia