Chapter II: Part 2

_Zeeman's Effect._--Faraday, after discovering the effect of a magnetic field on the plane of polarization of light, made numerous experiments to see if such a field influenced the nature of the light emitted by a luminous body, but without success. In 1885 Fievez,[44] a Belgian physicist, noticed that the spectrum of a sodium flame was changed slightly in appearance by a magnetic field; but his observation does not seem to have attracted much attention, and was probably ascribed to secondary effects. In 1896 Zeeman[45] saw a distinct broadening of the lines of lithium and sodium when the flames containing salts of these metals were between the poles of a powerful electromagnet; following up this observation, he obtained some exceedingly remarkable and interesting results, of which those observed with the blue-green cadmium line may be taken as typical. He found that in a strong magnetic field, when the lines of force are parallel to the direction of propagation of the light, the line is split up into a doublet, the constituents of which are on opposite sides of the undisturbed position of the line, and that the light in the constituents of this doublet is circularly polarized, the rotation in the two lines being in opposite directions. When the magnetic force is at right angles to the direction of propagation of the light, the line is resolved into a triplet, of which the middle line occupies the same position as the undisturbed line; all the constituents of this triplet are plane-polarized, the plane of polarization of the middle line being at right angles to the magnetic force, while the outside lines are polarized on a plane parallel to the lines of magnetic force. A great deal of light is thrown on this phenomenon by the following considerations due to H. A. Lorentz.[46]

Let us consider an ion attracted to a centre of force by a force
proportional to the distance, and acted on by a magnetic force
parallel to the axis of z: then if m is the mass of the particle and e
its charge, the equations of motion are

d²x dy
m --- + ax = -He --;
dt² dt

d²y dx
m --- + ay = He --;
dt² dt

d²z
m --- + ax = 0.
dt²

The solution of these equations is

x = A cos (p1t + [beta]) + B cos (p2t + [beta]1)

y = A sin (p1t + [beta]) - B sin (p2t + [beta]1)

z = C cos (pt + [gamma])

where

a - mp1² = - He p1

a - mp2² = He p2

p² = [alpha]/m,

or approximately

He He
p1 = p + ½ ---, p2 = p - ½ ---.
m m

Thus the motion of the ion on the xy plane may be regarded as made up
of two circular motions in opposite directions described with
frequencies p1 and p2 respectively, while the motion along z has the
period p, which is the frequency for all the vibrations when H = 0.
Now suppose that the cadmium line is due to the motion of such an ion;
then if the magnetic force is along the direction of propagation, the
vibration in this direction has its period unaltered, but since the
direction of vibration is perpendicular to the wave front, it does not
give rise to light. Thus we are left with the two circular motions in
the wave front with frequencies p1 and p2 giving the circularly
polarized constituents of the doublet. Now suppose the magnetic force
is at right angles to the direction of propagation of the light; then
the vibration parallel to the magnetic force being in the wave front
produces luminous effects and gives rise to a plane-polarized ray of
undisturbed period (the middle line of the triplet), the plane of
polarization being at right angles to the magnetic force. The
components in the wave-front of the circular orbits at right angles to
the magnetic force will be rectilinear motions of frequency p1 and p2
at right angles to the magnetic force--so that they will produce
plane-polarized light, the plane of polarization being parallel to the
magnetic force; these are the outer lines of the triplet.

If Zeeman's observations are interpreted from this point of view, the directions of rotation of the circularly-polarized light in the doublet observed along the lines of magnetic force show that the ions which produce the luminous vibrations are _negatively_ electrified, while the measurement of the charge of frequency due to the magnetic field shows that e/m is of the order 10^7. This result is of great interest, as this is the order of the value of e/m in the negatively electrified particles which constitute the Cathode Rays (see CONDUCTION, ELECTRIC III. _Through Gases_). Thus we infer that the "cathode particles" are found in bodies, even where not subject to the action of intense electrical fields, and are in fact an ordinary constituent of the molecule. Similar particles are found near an incandescent wire, and also near a metal plate illuminated by ultra-violet light. The value of e/m deduced from the Zeeman effect ranges from 10^7 to 3.4 × 10^7, the value of e/m for the particle in the cathode rays is 1.7 × 10^7. The majority of the determinations of e/m from the Zeeman effect give numbers larger than this, the maximum being about twice this value.

A more extended study of the behaviour of the spectroscopic lines has afforded examples in which the effects produced by a magnet are more complicated than those we have described, indeed the simple cases are much less numerous than the more complex. Thus Preston[47] and Cornu[48] have shown that under the action of a transverse magnetic field one of the D lines splits up into four, and the other into six lines; Preston has given many other examples of these quartets and sextets, and has shown that the change in the frequency, which, according to the simple theory indicated, should be the same for all lines, actually varies considerably from one line to another, many lines showing no appreciable displacement. The splitting up of a single line into a quartet or sextet indicates, from the point of view of the ion theory, that the line must have its origin in a system consisting of more than one ion. A single ion having only three degrees of freedom can only have three periods. When there is no magnetic force acting on the ion these periods are equal, but though under the action of a magnetic force they are separated, their number cannot be increased. When therefore we get four or more lines, the inference is that the system giving the lines must have at least four degrees of freedom, and therefore must consist of more than one ion. The theory of a system of ions mutually influencing each other shows, as we should expect, that the effects are more complex than in the case of a single ion, and that the change in the frequency is not necessarily the same for all systems (see J. J. Thomson, _Proc. Camb. Phil. Soc._ 13, p. 39). Preston[49] and Runge and Paschen have proved that, in some cases at any rate, the change in the frequency of the different lines is of such a character that they can be grouped into series such that each line in the series has the same change in frequency for the same magnetic force, and, moreover, that homologous lines in the spectra of different metals belonging to the same group have the same change in frequency.

A very remarkable case of the Zeeman effect has been discovered by H. Becquerel and Deslandres (_Comptes rendus_, 127, p. 18). They found lines in iron when the most deflected components are those polarized in the plane at right angles to the magnetic force. On the simple theory the light polarized in this way is not affected. Thus the behaviour of the spectrum in the magnetic field promises to throw great light on the nature of radiation, and perhaps on the constitution of the elements. The study of these effects has been greatly facilitated by the invention by Michelson[50] of the echelon spectroscope.

There are some interesting phenomena connected with the Zeeman effect which are more easily observed than the effect itself. Thus Cotton[51] found that if we have two Bunsen flames, A and B, coloured by the same salt, the absorption of the light of one by the other is diminished if either is placed between the poles of a magnet: this is at once explained by the Zeeman effect, for the times of vibration of the molecules of the flame in the magnetic field are not the same as those of the other flame, and thus the absorption is diminished. Similar considerations explain the phenomenon observed by Egoroff and Georgiewsky,[52] that the light emitted from a flame in a transverse field is partially polarized in a plane parallel to the magnetic force; and also Righi's[53] observation that if a sodium flame is placed in a longitudinal field between two crossed Nicols, and a ray of white light sent through one of the Nicols, then through the flame, and then through the second Nicol, the amount of light passing through the second Nicol is greater when the field is on than when it is off. Voight and Wiechert (_Wied. Ann._ 67, p. 345) detected the double refraction produced when light travels through a substance exposed to a magnetic field at right angles to the path of the light; this result had been predicted by Voight from theoretical considerations. Jean Becquerel has made some very interesting experiments on the effect of a magnetic field on the fine absorption bands produced by xenotime, a phosphate of yttrium and erbium, and tysonite, a fluoride of cerium, lanthanum and didymium, and has obtained effects which he ascribes to the presence of positive electrons. A very complete account of magneto- and electro-optics is contained in Voight's _Magneto- and Elektro-optik_.

FOOTNOTES:

[1] _Experimental Researches_, Series 19.

[2] _Comptes rendus_, 88, p. 709.

[3] _Wied. Ann._ 6, p. 332; 8, p. 278; 10, p. 257.

[4] _Wied. Ann._ 23, p. 228; 27, p. 191.

[5] _Wied. Ann._ 31, p. 941.

[6] _Phil. Trans._, A. 1885, Pt. 11, p. 343.

[7] _Wied. Ann._ 26, p. 456.

[8] _Phil. Trans._, A. 1895, Pt. 17, p. 621.

[9] _Wied. Ann._ 24, p. 161.

[10] _Wied. Ann._ 31, p. 970.

[11] _Comptes rendus_, 57, p. 670.

[12] _Comptes rendus_, 43, p. 529; 44, p. 1209.

[13] _Journ. Chem. Soc._ 1884, p. 421; 1886, p. 177; 1887, pp. 362
and 808; 1888, p. 561; 1889, pp. 680 and 750; 1891, p. 981; 1892, p.
800; 1893, pp. 75, 99 and 488.

[14] _Wied. Ann._ 44, p. 377.

[15] _Wied. Ann._ 43, p. 280.

[16] _Zeitschrift f. physikal. Chem._ 11, p. 753.

[17] _Phil. Mag._ [5] 3, p. 321.

[18] _Ann. de chim. et de phys._ [6] 4, p. 433; 9, p. 65; 10, p. 200.

[19] _Wied. Ann._ 23, p. 228; 27, p. 191.

[20] _Wied. Ann._ 39, p. 25.

[21] _Wied. Ann._ 42, p. 115.

[22] _Phil. Mag._ [5] 12, p. 171.

[23] _Journ. de Phys._ 1884, p. 360.

[24] _Beiblätter zu Wied. Ann._ 1885, p. 275.

[25] _Messungen über d. Kerr'sche Erscheinung._ Inaugural Dissert.
Leiden, 1893.

[26] _Phil. Mag._ [5] 5, p. 161.

[27] _Phil. Mag._ [3] 28, p. 469.

[28] _Die Magn. Drehung d. Polarisationsebene des Lichts_, Halle,
1863.

[29] _Electricity and Magnetism_, chap. xxi.

[30] _Phil. Trans._ 1880 (2), p. 691.

[31] _Phil. Mag._ (5) 11, p. 254, 1881.

[32] _Arch. Néerl._ 19, p. 123.

[33] _Wied. Ann._ 23, p. 493; 67, p. 345.

[34] _Wied. Ann._ 24, p. 119.

[35] _Wied. Beiblätter_, 8, p. 869.

[36] _Comptes rendus_, 108, p. 510.

[37] _Phil. Trans._ 182, A. p. 371, 1892; _Physical Optics_, p. 393.

[38] _Wied. Ann._ 46, p. 71; 47, p. 345; 48, p. 740; 50, p. 722.

[39] _Wied. Ann._ 46, p. 353; 48, p. 122; 49, p. 690.

[40] _Recent Researches_, p. 489 et seq.

[41] _Phil. Trans._, A. 1897, p. 89.

[42] _Brit. Assoc. Report_, 1893.

[43] _Comptes rendus_, 127, p. 548.

[44] _Bull. de l'Acad. des Sciences Belg._ (3) 9, pp. 327, 381, 1885;
12 p. 30, 1886.

[45] _Communications from the Physical Laboratory_, Leiden, No. 33,
1896; Phil. Mag. 43, p. 226; 44, pp. 55 and 255; and 45, p. 197.

[46] _Arch. Néerl._ 25, p. 190.

[47] _Phil. Mag._ 45, p. 325; 47, p. 165.

[48] _Comptes rendus_, 126, p. 181.

[49] _Phil. Mag._ 46, p. 187.

[50] _Phil. Mag._ 45, p. 348.

[51] _Comptes rendus_, 125, p. 865.

[52] _Comptes rendus_, pp. 748 and 949, 1897.

[53] _Comptes rendus_, 127, p. 216; 128, p. 45.

(J. J. T.)

MAGNOLIA, the typical genus of the botanical order Magnoliaceae, named after Pierre Magnol (1638-1715), professor of medicine and botany at Montpellier. It contains about twenty species, distributed in Japan, China and the Himalayas, as well as in North America.

Magnolias are trees or shrubs with deciduous or rarely evergreen foliage. They bear conspicuous and often large, fragrant, white, rose or purple flowers. The sepals are three in number, the petals six to twelve, in two to four series of three in each, the stamens and carpels being numerous. The fruit consists of a number of follicles which are borne on a more or less conical receptacle, and dehisce along the outer edge to allow the scarlet or brown seeds to escape; the seeds however remain suspended by a long slender thread (the funicle). Of the old-world species, the earliest in cultivation appears to have been _M. Yulan_ (or _M. conspicua_) of China, of which the buds were preserved, as well as used medicinally and to season rice; together with the greenhouse species, _M. fuscata_, it was transported to Europe in 1789, and thence to North America, and is now cultivated in the Middle States. There are many fine forms of _M. conspicua_, the best being _Soulangeana_, white tinted with purple, _Lenné_ and _stricta_. Of the Japanese magnolias, _M. Kobus_ and the purple-flowered _M. obovata_ were met with by Kaempfer in 1690, and were introduced into England in 1709 and 1804 respectively. _M. pumila_, the dwarf magnolia, from the mountains of Amboyna, is nearly evergreen, and bears deliciously scented flowers; it was introduced in 1786. The Indian species are three in number, _M. globosa_, allied to _M. conspicua_ of Japan, _M. sphenocarpa_, and, the most magnificent of all magnolias, _M. Campbellii_, which forms a conspicuous feature in the scenery and vegetation of Darjeeling. It was discovered by Dr Griffith in Bhutan, and is a large forest tree, abounding on the outer ranges of Sikkim, 80 to 150 ft. high, and from 6 to 12 ft. in girth. The flowers are 6 to 10 in. across, appearing before the leaves, and vary from white to a deep rose colour.

The first of the American species brought to Europe (in 1688 by John Banister) was _M. glauca_, a beautiful evergreen species about 15 ft. high with obtuse leathery leaves, blue-green above, silvery underneath, and globular flowers varying from creamy white to pale yellow with age. It is found in low situations near the sea from Massachusetts to Louisiana--more especially in New Jersey and the Carolinas. _M. acuminata_, the so-called "cucumber tree," from the resemblance of the young fruits to small cucumbers, ranges from Pennsylvania to Carolina. The wood is yellow, and used for bowls; the flowers, 3 to 4 in. across, are glaucous green tinted with yellow. It was introduced into England from Virginia about 1736. _M. tripetala_ (or _M. umbrella_), is known as the "umbrella tree" from the arrangement of the leaves at the ends of the branches resembling somewhat that of the ribs of an umbrella. The flowers, 5 to 8 in. across, are white and have a strong but not disagreeable scent. It was brought to England in 1752. _M. Fraseri_ (or _M. auriculata_), discovered by John Bartram in 1773, is a native of the western parts of the Carolinas and Georgia, extending southward to western Florida and southern Alabama. It grows 30 to 50 ft. high, has leaves a foot or more long, heart-shaped and bluntly auricled at the base, and fragrant pale yellowish-white flowers, 3 to 4 in. across. The most beautiful species of North America is _M. grandiflora_, the "laurel magnolia," a native of the south-eastern States, and introduced into England in 1734. It grows a straight trunk, 2 ft. in diameter and upwards of 70 ft. high, bearing a profusion of large, powerfully lemon-scented creamy-white flowers. It is an evergreen tree, easily recognized by its glossy green oval oblong leaves with a rusty-brown under surface. In England it is customary to train it against a wall in the colder parts, but it does well as a bush tree; and the original species is surpassed by the Exmouth varieties, which originated as seedlings at Exeter from the tree first raised in England by Sir John Colliton, and which flower much more freely than the parent plant. Other fine magnolias now to be met with in gardens are _M. cordata_, a North American deciduous tree 40 to 50 ft. high, with heart-shaped leaves, woolly beneath, and yellow flowers lined with purple; _M. hypoleuca_, a fine Japanese tree 60 ft. high or more, with leaves a foot or more long, 6 to 7 in. broad, the under surface covered with hairs; _M. macrophylla_, a handsome deciduous North American tree, with smooth whitish bark, and very large beautiful green leaves, 1 to 3 ft. long, 8 to 10 in. broad, oblong-obovate and heart-shaped at the base; the open sweet-scented bell-shaped flowers 8 to 10 in. across, are white with a purple blotch at the base of the petals; _M. stellata_ or _Halleana_, a charming deciduous Japanese shrub remarkable for producing its pure white starry flowers as early as February and March on the leafless stems; and _M. Watsoni_, another fine deciduous Japanese bush or small tree with very fragrant pure white flowers 5 to 6 in. across.

1. Flower after removal of the sepals and petals, showing the
indefinite stamens, s, and carpels, c.

2. Fruit--the ripe carpels are splitting, exposing the seeds, some of
which are suspended by the long funicle.

3. Floral diagram, b, bract.]

The tulip tree, _Liriodendron tulipifera_, a native of North America, frequently cultivated in England, is also a member of the same family. It reaches a height of over 100 ft. in a native condition, and as much as 60 to 80 ft. in England. It resembles the plane tree somewhat in appearance, but is readily recognized by lobed leaves having the apical lobe truncated, and by its soft green and yellow tulip-like flowers--which however are rarely borne on trees under twenty years of age.

For a description of the principal species of magnolia under
cultivation see J. Weathers, _Practical Guide to Garden Plants_, pp.
174 seq., and for a detailed account of the American species see C. S.
Sargent, _Silva of North America_, vol. i.

MAGNUS, HEINRICH GUSTAV (1802-1870), German chemist and physicist, was born at Berlin on the 2nd of May 1802. His father was a wealthy merchant; and of his five brothers one, Eduard (1799-1872), became a celebrated painter. After studying at Berlin, he went to Stockholm to work under Berzelius, and later to Paris, where he studied for a while under Gay-Lussac and Thénard. In 1831 he returned to Berlin as lecturer on technology and physics at the university. As a teacher his success was rapid and extraordinary. His lucid style and the perfection of his experimental demonstrations drew to his lectures a crowd of enthusiastic scholars, on whom he impressed the importance of applied science by conducting them round the factories and workshops of the city; and he further found time to hold weekly "colloquies" on physical questions at his house with a small circle of young students. From 1827 to 1833 he was occupied mainly with chemical researches, which resulted in the discovery of the first of the platino-ammonium compounds ("Magnus's green salt" is PtCl2, 2NH3), of sulphovinic, ethionic and isethionic acids and their salts, and, in conjunction with C. F. Ammermüller, of periodic acid. Among other subjects at which he subsequently worked were the absorption of gases in blood (1837-1845), the expansion of gases by heat (1841-1844), the vapour pressures of water and various solutions (1844-1854), thermo-electricity (1851), electrolysis (1856), induction of currents (1858-1861), conduction of heat in gases (1860), and polarization of heat (1866-1868). From 1861 onwards he devoted much attention to the question of diathermancy in gases and vapours, especially to the behaviour in this respect of dry and moist air, and to the thermal effects produced by the condensation of moisture on solid surfaces.

In 1834 Magnus was elected extraordinary, and in 1845 ordinary professor at Berlin. He was three times elected dean of the faculty, in 1847, 1858 and 1863; and in 1861, rector magnificus. His great reputation led to his being entrusted by the government with several missions; in 1865 he represented Prussia in the conference called at Frankfort to introduce a uniform metric system of weights and measures into Germany. For forty-five years his labour was incessant; his first memoir was published in 1825 when he was yet a student; his last appeared shortly after his death on the 4th of April 1870. He married in 1840 Bertha Humblot, of a French Huguenot family settled in Berlin, by whom he left a son and two daughters.

See _Allgemeine deutsche Biog._ The Royal Society's _Catalogue_
enumerates 84 papers by Magnus, most of which originally appeared in
_Poggendorff's Annalen_.

MAGNY, CLAUDE DRIGON, MARQUIS DE (1797-1879), French heraldic writer, was born in Paris. After being employed for some time in the postal service, he devoted himself to the study of heraldry and genealogy, his work in this direction being rewarded by Pope Gregory XVI. with a marquisate. He founded a French college of heraldry, and wrote several works on heraldry and genealogy, of which the most important were _Archives nobiliaires universelles_ (1843) and _Livre d'or de la noblesse de France_ (1844-1852). His two sons, Edouard Drigon and Achille Ludovice Drigon, respectively comte and vicomte de Magny, also wrote several works on heraldry.

MAGO, the name of several Carthaginians, (1) The reputed founder of the military power of Carthage, fl. 550-500 B.C. (Justin xviii. 7, xix. i). (2) The youngest of the three sons of Hamilcar Barca. He accompanied Hannibal into Italy, and held important commands in the great victories of the first three years. After the battle of Cannae (216 B.C.) he sailed to Carthage to report the successes gained. He was about to return to Italy with strong reinforcements for Hannibal, when the government ordered him to go to the aid of his other brother, Hasdrubal, who was hard pressed in Spain. He carried on the war there with varying success in concert with the two Hasdrubals until, in 209, his brother marched into Italy to help Hannibal. Mago remained in Spain with Hasdrubal, the son of Gisco. In 207 he was defeated by M. Junius Silanus, and in 206 the combined forces of Mago and Hasdrubal were scattered by Scipio Africanus in the decisive battle of Silpia. Mago maintained himself for some time in Gades, but afterwards received orders to carry the war into Liguria. He wintered in the Balearic Isles, where the harbour Portus Magonis (Port Mahon) still bears his name. Early in 204 he landed in Liguria, where he maintained a desultory warfare till in 203 he was defeated in Cisalpine Gaul by the Roman forces. Shortly afterwards he was ordered to return to Carthage, but on the voyage home he died of wounds received in battle.

See Polybius iii.; Livy xxi.-xxiii.; xxviii., chs. 23-37; xxix., xxx.;
Appian, _Hispanica_, 25-37; T. Friedrich, _Biographie des Barkiden
Mago_; H. Lehmann, _Der Angriff der drei Barkiden auf Italien_
(Leipzig, 1905); and further J. P. Mahaffy, in _Hermathena_, vii.
29-36 (1890).

(3) The name of Mago is also attached to a great work on agriculture which was brought to Rome and translated by order of the senate after the destruction of Carthage. The book was regarded as a standard authority, and is often referred to by later writers.

See Pliny, _Nat. Hist_, xviii. 5; Columella, i. 1; Cicero, _De
oratore_, i. 58.

MAGPIE, or simply PIE (Fr. _pie_), the prefix being the abbreviated form of a human name (Margaret[1]), a bird once common throughout Great Britain, though now nearly everywhere scarce. Its pilfering habits have led to this result, yet the injuries it causes are exaggerated by common report; and in many countries of Europe it is still the tolerated or even the cherished neighbour of every farmer, as it formerly was in England if not in Scotland also. It did not exist in Ireland in 1617, when Fynes Morison wrote his _Itinerary_, but it had appeared there within a hundred years later, when Swift mentions its occurrences in his _Journal to Stella_, 9th July 1711. It is now common enough in that country, and there is a widespread but unfounded belief that it was introduced by the English out of spite. It is a species that when not molested is extending its range, as J. Wolley ascertained in Lapland, where within the last century it has been gradually pushing its way along the coast and into the interior from one fishing-station or settler's house to the next, as the country has been peopled.

Since the persecution to which the pie has been subjected in Great Britain, its habits have altered greatly. It is no longer the merry, saucy hanger-on of the homestead, but is become the suspicious thief, shunning the gaze of man, and knowing that danger may lurk in every bush. Hence opportunities of observing it fall to the lot of few, and most persons know it only as a curtailed captive in a wicker cage, where its vivacity and natural beauty are lessened or wholly lost. At large few European birds possess greater beauty, the pure white of its scapulars and inner web of the flight-feathers contrasting vividly with the deep glossy black on the rest of its body and wings, while its long tail is lustrous with green, bronze, and purple reflections. The pie's nest is a wonderfully ingenious structure, placed either in high trees or low bushes, and so massively built that it will stand for years. Its foundation consists of stout sticks, turf and clay, wrought into a deep, hollow cup, plastered with earth, and lined with fibres; but around this is erected a firmly interwoven, basket-like outwork of thorny sticks, forming a dome over the nest, and leaving but a single hole in the side for entrance and exit, so that the whole structure is rendered almost impregnable. Herein are laid from six to nine eggs, of a pale bluish-green freckled with brown and blotched with ash-colour. Superstition as to the appearance of the pie still survives even among many educated persons, and there are several versions of a rhyming adage as to the various turns of luck which its presenting itself, either alone or in company with others, is supposed to betoken, though all agree that the sight of a single pie presages sorrow.

The pie belongs to the same family of birds as the crow, and is the _Corvus pica_ of Linnaeus, the _Pica caudata_, _P. melanoleuca_, or _P. rustica_ of modern ornithologists, who have recognized it as forming a distinct genus, but the number of species thereto belonging has been a fruitful source of discussion. Examples from the south of Spain differ slightly from those inhabiting the rest of Europe, and in some points more resemble the _P. mauritanica_ of north-western Africa; but that species has a patch of bare skin of a fine blue colour behind the eye, and much shorter wings. No fewer than five species have been discriminated from various parts of Asia, extending to Japan; but only one of them, the _P. leucoptera_ of Turkestan and Tibet, has of late been admitted as valid. In the west of North America, and in some of its islands, a pie is found which extends to the upper valleys of the Missouri and the Yellowstone, and has long been thought entitled to specific distinction as _P. hudsonia_; but its claim thereto is now disallowed by some of the best ornithologists of the United States, and it can hardly be deemed even a geographical variety of the Old-World form. In California, however, there is a permanent race if not a good species, _P. nuttalli_, easily distinguishable by its yellow bill and the bare yellow skin round its eyes; on two occasions in the year 1867 a bird apparently similar was observed in Great Britain (_Zoologist_, ser. 2, pp. 706, 1016). (A. N.)

FOOTNOTE:

[1] "Magot" and "Madge," with the same origin, are names, frequently
given in England to the pie; while in France it is commonly known as
_Margot_, if not termed, as it is in some districts, _Jaquette_.

MAGWE, a district in the Minbu division of Upper Burma. Area, 2913 sq. m.; pop. (1901), 246,708, showing an increase of 12.38% in the decade. Magwe may be divided into two portions: the low, flat country in the Taungdwingyi subdivision, and the undulating high ground extending over the rest of the district. In Taungdwingyi the soil is rich, loamy, and extremely fertile. The plain is about 45 m. from north to south. At its southern extremity it is about 30 m. wide, and lessens in width to the north till it ends in a point at Natmauk. On the east are the Pegu Yomas, which at some points reach a height of 1500 ft. A number of streams run westwards to the Irrawaddy, of which the Yin and the Pin, which form the northern boundary, are the chief. The only perennial stream is the Yanpè. Rice is the staple product, and considerable quantities are exported. Sesamum of very high quality, maize, and millet are also cultivated, as well as cotton in patches here and there over the whole district.

In this district are included the well-known Yenangyaung petroleum
wells. The state wells have been leased to the Burma Oil Company. The
amount of oil-bearing lands is estimated at 80 sq. m. and the portion
not leased to the company has been demarcated into blocks of 1 sq. m.
and offered on lease. The remaining land belongs to hereditary Burmese
owners called _twinsa_, who dig wells and extract their oil by the
rope and pulley system as they have always done. Lacquered wood trays,
bowls and platters, and cart-wheels, are the only manufactures of any
note in the district.

The annual rainfall averages about 27 inches. The maximum temperature
rises to a little over 100° in the hot season, and falls to an average
minimum of 53° and 54° in the cold season.

The town of Magwe is the headquarters of the district; pop. (1901),
6232. It is diagonally opposite Minbu, the headquarters of the
division, on the right bank of the Irrawaddy.

MAGYARS, the name of the dominant race in Hungary, or Hungarians proper. Though they have become physically assimilated to the western peoples, they belong in origin and language to the Finno-Ugrian (q.v.) division of the Ural-Altaic race. They form barely half of the population of Hungary, but are by far the largest and most compact of all its racial groups. Magyar is the official language of Hungary, the official name of which (_Magyarorzág_, or "country of the Magyars") enshrines the Magyar claim to predominance. While all Magyars are properly Hungarians, all Hungarians are not necessarily Magyars. "Hungarian" may be used as a generic term covering all the various races of Hungary, while "Magyar" is strictly specific to a single group. The Magyars themselves, indeed, sometimes apply the name _Magyarorzág_ to Hungary "proper," excluding Croatia-Slavonia, the whole kingdom being called _Magyarbirodalom_, the Magyar monarchy or realm. See HUNGARY.

MAHABALESHWAR, or MALCOLMPETH, a hill station in Satara district, and the principal sanatorium in the Bombay presidency, India. Pop. (1901), 5299. It is reached by carriage from Wathar railway station (39 m.) or by motor car from Poona (119 m.). Mahabaleshwar occupies the summit of a ridge of the Western Ghats, with a general elevation of 4500 ft. above sea-level. It was established in 1828 by Sir John Malcolm, governor of Bombay, who obtained the site from the raja of Satara in exchange for another patch of territory. The superior elevation of Mahabaleshwar renders it much cooler than Matheran (2460 ft.), a sanatorium about 50 m. E. of Bombay, but its heavy rainfall (292 in. annual average) makes it almost uninhabitable during the rainy season. The mean annual temperature is 67° F. In the hottest season (March-April) an extreme of a little over 90° is reached during the day. Mahabaleshwar forms the retreat usually during spring, and occasionally in autumn, of the governor of Bombay, and the chief officers of his establishment, and has the usual public buildings of a first-class sanatorium.

MAHAFFY, JOHN PENTLAND (1839- ), Irish classical scholar, was born in Switzerland on the 12th of July 1839. He received his early education in Switzerland and Germany, and later at Trinity College, Dublin, where he held the professorship of ancient history. Mahaffy, a man of great versatility, published numerous works, some of which, especially those dealing with what may be called the Silver age of Greece, became standard authorities. The following deserve mention: _History of Classical Greek Literature_ (4th ed., 1903 seq.); _Social Life in Greece from Homer to Menander_ (4th ed., 1903); _The Silver Age of the Greek World_ (1906); _The Empire of the Ptolemies_ (1896); _Greek Life and Thought from Alexander to the Roman Conquest_ (2nd ed., 1896); _The Greek World under Roman Sway from Polybius to Plutarch_ (1890). His translation of Kuno Fischer's _Commentary on Kant_ (1866) and his own exhaustive analysis, with elucidations, of Kant's critical philosophy are of great value. He also edited the Petrie papyri in the _Cunningham Memoirs_ (3 vols. 1891-1905).

MAHALLAT, a province of central Persia, situated between Kashan and Irak. Pop. about 20,000; yearly revenue about £2500. Until 1890 it was one of the five "central provinces" (the other four being Irak, Ferahan, Kezzaz, and Savah), which were under a governor appointed by the shah; since then it has formed part of the Isfahan government. It is traversed by the Anarbar or Kum River, and comprises the city of Mahallat, divided into upper and lower, or Rivkan and Zanjirvan, and twenty-two flourishing villages. It was known in former times as Anar, the Anarus of Peutinger's tables. The city, capital of the province, is situated at an elevation of 5850 ft. in 33° 51´ N., 50° 30´ E.; pop. about 9000.

MAHAN, ALFRED THAYER (1840- ), American naval officer and historian, was born on the 27th of September 1840 at West Point, New York. His father, Dennis Hart Mahan (1802-1871) was a professor in the military academy, and the author of textbooks on civil and military engineering. The son graduated at the naval academy in 1859, became lieutenant in 1861, served on the "Congress," and on the "Pocahontas," "Seminole," and "James Adger" during the Civil War, and was instructor at the naval academy for a year. In 1865 he was made lieut.-commander, commander in 1872, captain in 1885. Meanwhile he saw service in the Gulf of Mexico, the South Atlantic, the Pacific, and Asia, and did shore duty at Boston, New York and Annapolis. In 1886-89 he was president of the naval war college at Newport, Rhode Island. Between 1889 and 1892 he was engaged in special service for the bureau of navigation, and in 1893 was made commander of the "Chicago," of the European squadron. In 1896 he retired from active service, but was a member of the naval board of strategy during the war between the United States and Spain. He was a member of the peace congress at the Hague in 1899. This long and varied service gave him extensive opportunities for observation, which he supplemented by constant study of naval authorities and reflection on the interpretation of the problems of maritime history. His first book was a modest and compact story of the affairs in _The Gulf and Inland Waters_ (1883), in a series of volumes by various writers, entitled _The Navy in the Civil War_; in 1890 he suddenly acquired fame by the appearance of his masterly work entitled _The Influence of Sea Power upon History, 1660-1783_. Having been impressed by the failure of historians to allow for the influence of sea power in struggles between nations, he was led to make prolonged investigations of this general theme (see SEA POWER). The reception accorded the volume was instant and hearty; in England, in particular, it was deemed almost an epoch-making work, and was studied by naval specialists, cabinet ministers and journalists, as well as by a large part of the general public. It was followed by _The Influence of Sea Power upon the French Revolution and Empire_ (2 vols. 1892); _The Life of Nelson, the Embodiment of the Sea Power of Great Britain_ (1897); and _Sea Power in its Relations to the War of 1812_ (1905). The author's general aim in these works--some of which have been translated into French, German and Japanese--was to make the consideration of maritime matters paramount to that of military, political or economic movements, without, however, as he himself says "divorcing them from their surroundings of cause and effect in general history, but seeking to show how they modified the latter, and were modified by them." He selected the year 1660 as the beginning of his narrative, as being the date when the "sailing-ship era, with its distinctive features, had fairly begun." The series as a whole has been accepted as finally authoritative, supplanting its predecessors of similar aim, and almost--in the words of Theodore Roosevelt--founding a new school of naval historical writing.

Other works by Mahan are a _Life of Admiral Farragut_ (1892); _The
Interest of America in Sea Power_ (1897); _Lessons of the War with
Spain_ (1899); _The Story of the War with South Africa_ and _The
Problem of Asia_ (1900); _Types of Naval Officers drawn from the
History of the British Navy_ (1901); _Retrospect and Prospect_,
studies of international relations (1902).

MAHANADI, or MAHANUDDY ("The Great River"), a river of India. It rises in 20° 10´ N., 82° E., 25 m. S. of Raipur town, in the wild mountains of Bastar in the Central Provinces. At first an insignificant stream, taking a northerly direction, it drains the eastern portion of the Chhattisgarh plain, then a little above Seorinarayan it receives the waters which its first great affluent, the Seonath, has collected from the western portion of the plain; thence flowing for some distance due E., its stream is augmented by the drainage of the hills of Uprora, Korba, and the ranges that separate Sambalpur from Chota Nagpur. At Padampur it turns towards the south, and struggling through masses of rock, flows past the town of Sambalpur to Sonpur. From Sonpur it pursues a tortuous course among ridges and rocky crags towards the range of the Eastern Ghats. This mountain line it pierces by a gorge about 40 m. in length, overlooked by forest-clad hills. Since the opening of the Bengal-Nagpur railway, the Mahanadi is little used for navigation. It pours down upon the Orissa delta at Naraj, about 7 m. west of Cuttack town; and after traversing Cuttack district from west to east, and throwing off numerous branches (the Katjori, Paika, Biropa, Chitartala, &c.) it falls into the Bay of Bengal at False Point by several channels.

The Mahanadi has an estimated drainage area of 43,800 sq. m., and its
rapid flow renders its maximum discharge in time of flood second to
that of no other river in India. During unusually high floods
1,500,000 cub. ft. of water pour every second through the Naraj gorge,
one-half of which, uncontrolled by the elaborate embankments, and
heavily laden with silt, pours over the delta, filling the swamps,
inundating the rice-fields, and converting the plains into a sea. In
the dry weather the discharge of the Mahanadi dwindles to 1125 cub.
ft. per second. Efforts have been made to husband and utilize the vast
water supply thrown upon the Orissa delta during seasons of flood.
Each of the three branches into which the parent stream splits at the
delta head is regulated by a weir. Of the four canals which form the
Orissa irrigation system, two take off from the Biropa weir, and one,
with its branch, from the Mahanadi weir. On the 31st of December 1868
the government took over the whole canal works from the East Indian
Irrigation Company, at a cost of £941,368. The canals thus taken over
and since completed, are the high-level canal, the Kendrapara canal,
the Taldanda canal and the Machgaon canal, irrigating 275,000 acres.

MAHANOY CITY, a borough of Schuylkill county, Pennsylvania, U.S.A., 56 m. N.E. of Harrisburg. Pop. (1890), 11,286; (1900), 13,504, of whom 3877 were foreign-born, mostly Slavs; (1910 census) 15,936. It is served by branches of the Lehigh Valley and the Philadelphia & Reading railways. The borough is situated in the valley of Mahanoy Creek, and has an elevation of 1240 ft. above the sea; Broad Mountain (1795 ft.), a ridge extending through Schuylkill county, overlooks it on the S.E. The valley is a part of the anthracite coal region of Pennsylvania, fire clay abounds in the vicinity, and the borough's principal industries are the mining and shipping of coal, and the manufacture of shirts and foundry products. Mahanoy City, originally a part of Mahanoy township (pop. in 1910, 6256), was incorporated as a borough in 1863.

MAHAR, the name of a servile caste in the Deccan, India. Their special function, apart from that of scavenger, is to act as village watchman, as guardian of the village boundaries, and as public messenger. In some parts they are also weavers of coarse cotton cloth. In 1901 their total number in all India was just under three millions.

MAHARAJPUR, a village in Gwalior state, Central India. Pop. (1901), 366. It was the scene of a battle (Dec. 29, 1843) in which Sir Hugh Gough, accompanied by the governor-general, Lord Ellenborough, defeated the insurgent army of the Gwalior state.

MAHAVAMSA, the _Great Chronicle_, a history of Ceylon from the 5th century B.C. to the middle of the 5th century A.D., written in Pali verse by Mahanama of the Dighasanda Hermitage, shortly after the close of the period with which it deals. In point of historical value it compares well with early European chronicles. In India proper the decipherment of early Indian inscriptions was facilitated to a very great extent by the data found only in the Mahavamsa. It was composed on the basis of earlier works written in Sinhalese, which are now lost, having been supplanted by the chronicles and commentaries in which their contents were restated in Pali in the course of the 5th century. The particular one on which our Mahavamsa was mainly based was also called the Mahavamsa, and was written in Sinhalese prose with Pali memorial verse interspersed. The extant Pali work gives legends of the Buddha and the genealogy of his family; a sketch of the history of India down to Asoka; an account of Buddhism in India down to the same date; a description of the sending out of missionaries after Asoka's council, and especially of the mission of Mahinda to Ceylon; a sketch of the previous history of Ceylon; a long account of the reign of Devanam-piya Tissa, the king of Ceylon who received Mahinda, and established Buddhism in the island; short accounts of the kings succeeding him down to Duttha Gamiin (Dadagamana or Dutegemunu); then a long account, amounting to an epic poem, of the adventures and reign of that prince, a popular hero, born in adversity, who roused the people, and drove the Tamil invaders out of the island. Finally we have short notices of the subsequent kings down to the author's time. The Mahavamsa was the first Pali book made known to Europe. It was edited in 1837, with English translation and an elaborate introduction, by George Turnour, then colonial secretary in Ceylon. Its vocabulary was an important part of the material utilized in Childer's _Pali Dictionary_. Its relation to the sources from which it drew has been carefully discussed by various scholars and in especial detail by Geiger. It is agreed that it gives a reasonably fair and correct presentation of the tradition preserved in the lost Sinhalese Mahavamsa; that, except in the earliest period, its list of kings, with the years of each reign, is complete and trustworthy; and that it gives throughout the view, as to events in Ceylon, of a resident in the Great Minster at Anuradhapura.

See _The Mahavamsa_, ed. by Geo. Turnour (Colombo, 1837); ed. by W.
Geiger (London, 1908); H. Oldenberg, in the introduction to his
edition of the _Dipavamsa_ (London, 1879); O. Franke, in _Wiener
Zeitschrift für die Kunde des Morgenlandes_ (1907); W. Geiger,
_Dipavamsa und Mahavamsa_ (Leipzig, 1905, trans. by Ethel M.
Coomaraswamy, Colombo, 1908). (T. W. R. D.)

MAHAYANA ("Great Vehicle"), the name given to the later Buddhism, the popular religion which embraced all the people and had its pantheon of Buddhas and Bodhisatvas, with attendant deities and demons, spacious temples and images, pompous ceremonial and noisy festivals. It was thus contrasted with the Hinayana ("Little Vehicle") of the primitive Buddhism which had been only for the select few. (See BUDDHISM.)

MAHDI (Arab. "he who is guided aright"), a title assumed by the third Abbasid caliph (see CALIPHATE: _Abbasids_, § 3). According to Moslem traditionists Mahomet declared that one of his descendants, the imam of God, who would fill the earth with equity and justice, would bear the name of al-mahdi. The Sunnis hold that this mahdi has not yet appeared. The name of mahdi is also given by the Shi'ite Mahommedans to the last of the imams of the house of 'Ali. It was under the name of al-mahdi that Mokhtar proclaimed 'Ali's son Mahommed as the opponent of the caliph Abdalmalik, and, according to Shahrastani, the doctrine of the mahdi, the hidden deliverer who is one day to appear and fill the oppressed world with righteousness, first arose in connexion with a belief that this Mahommed had not died but lived concealed at Mount Radwa, near Mecca, guarded by a lion and a panther. The hidden imam of the common Shi'ites is, however, the twelfth imam, Mahommed Abu'I-Qasim, who disappeared mysteriously in 879. The belief in the appearance of the mahdi readily lent itself to imposture. Of the many pretenders to this dignity known in all periods of Moslem history the most famous was the first caliph of the Fatimite dynasty in North Africa, 'Obaidallah al-Mahdi, who reigned 909-933. After him was named the first capital of the dynasty, the once important city of Mahdia (q.v.). Another great historical movement, headed by a leader who proclaimed himself the mahdi (Mahommed ibn Abdallah ibn Tumart), was that of the Almohades (q.v.). In 1881 Mahommed Ahmed ibn Seyyid Abdullah (q.v.), a Dongolese, proclaimed himself al-mahdi and founded in the eastern Sudan the short-lived empire overthrown by an Anglo-Egyptian force at the battle of Omdurman in 1898. Concurrently with the claim of Mahommed Ahmed to be the mahdi the same title was claimed by, or for, the head of the Senussites, a confraternity powerful in many regions of North Africa.

MAHDIA (also spelt _Mehdia_, _Mehedia_, &c.), a town of Tunisia, on the coast between the gulfs of Hammamet and Gabes, 47 m. by rail S.S.E. of Susa. Pop. about 8000. Mahdia is built on a rocky peninsula which projects eastward about a mile beyond the normal coast line, and is not more than a quarter of a mile wide. The extremity of the peninsula is called Ras Mahdia or Cape Africa--Africa being the name by which Mahdia was designated by Froissart and other European historians during the middle ages and the Renaissance. In the centre of the peninsula and occupying its highest point is a citadel (16th century); another castle farther west is now used as a prison and is in the centre of the native town. The European quarter and the new port are on the south-west side of the peninsula. The port is available for small boats only; steamers anchor in the roadstead about a quarter of a mile from the shore. On the south-east, cut out of the rock, is the ancient harbour, or _cothon_, measuring about 480 ft by 240 ft., the entrance being 42 ft. wide. There are manufactories of olive oil, but the chief industry is sardine fishing, largely in the hands of Italians.

Mahdia occupies the site of a Phoenician settlement and by some authorities is identified with the town called Turris Hannibalis by the Romans. Hannibal is said to have embarked here on his exile from Carthage. After the Arab conquest of North Africa the town fell into decay. It was refounded in 912 by the first Fatimite caliph, 'Obaidallah-al-Mahdi, after whom it was named. It became the port of Kairawan and was for centuries a city of considerable importance, largely owing to its great natural strength, and its position on the Mediterranean. It carried on an active trade with Egypt, Syria and Spain. The town was occupied by the Normans of Sicily in the 12th century, but after holding it for about twelve years they were driven out in 1159 by the Almohades. In 1390 a joint English and French force vainly besieged Mahdia for sixty-one days. In the early part of the 16th century the corsair Dragut seized the town and made it his capital, but in 1550 the place was captured by the Spaniards, who held it until 1574. Before evacuating the town the Spaniards dismantled the fortifications. Under the rule of the Turks and, later, the beys of Tunis Mahdia became a place of little importance. It was occupied by the French in 1881 without opposition, and regained some of its former commercial importance.

During 1908 numbers of bronzes and other works of art were recovered
from a vessel wrecked off Mahdia in the 5th century A.D. (see
_Classical Review_, June 1909).

MAHÉ, a French settlement in the Malabar district of Madras, India, situated in 11° 43´ N. and 75° 33´ E., at the mouth of a river of the same name. Area, 26 sq. m.; pop. (1901), 10,298. It is the only French possession on the west coast of India, and is in charge of a _chef de service_, subordinate to the governor-general at Pondicherry. It is now a decaying place.

MAHESHWAR, a town in Indore state, Central India, on the N. bank of the Narbada (Nerbudda). Pop. (1901), 7042. Though of great antiquity and also of religious sanctity, it is chiefly noted as the residence of Ahalya Bai, the reigning queen of the Holkar dynasty during the last half of the 18th century, whose ability and munificence are famous throughout India. Close by her cenotaph stands the family temple of the Holkars.

MAHI, a river of western India, which rises in Central India and, after flowing through south Rajputana, enters Gujarat and falls into the sea by a wide estuary near Cambay; total length, 300 m.; estimated drainage area, 16,000 sq. m. It has given its name to the Mahi Kantha agency of Bombay, and also to the mehwasis, marauding highlanders often mentioned in Mahommedan chronicles.

MAHI KANTHA, a political agency or collection of native states in India, within the Gujarat division of Bombay. Over half the territory is covered by the native state of Idar. There are eleven other chiefships, and a large number of estates belonging to Rajput or Koli thakurs, formerly feudatories of Baroda. Several of the states are under British administration. Total area, 3125 sq. m.; pop. (1901), 361,545, showing a decrease of 38% in the decade, due to famine; estimated revenue, £76,000; tribute (mostly to the gaekwar of Baroda), £9000. Many of the inhabitants belong to the wild tribes of Bhils and Kolis. In 1897 a metre-gauge railway was opened from Ahmedabad through Parantij to Ahmednagar. At Sadra is the Scott College for the education of the sons of chiefs on the lines of an English public school. There are also Anglo-vernacular schools at Sadra, Idar and Mansa. The famine of 1899-1900 was severely felt in this tract.

MAHMUD I. (1696-1754), sultan of Turkey, was the son of Mustafa II., and succeeded his uncle Ahmed III. in 1730. After the suppression of a military revolt the war with Persia was continued with varying success, and terminated in 1736 by a treaty of peace restoring the _status quo ante bellum_. The next enemy whom Turkey was called upon to face was Russia, later joined by Austria. War went on for four years; the successes gained by Russia were outweighed by Austria's various reverses, terminating by the defeat of Wallis at Krotzka, and the peace concluded at Belgrade was a triumph for Turkish diplomacy. The sultan, throughout desirous for peace, is said to have been much under the influence of the chief eunuch, Haji Beshir Aga. In 1754 Mahmud died of heart-disease when returning from the Friday service at the mosque. He had a passion for building, to which are due numberless kiosques, where nocturnal orgies were carried on by him and his boon companions. In this reign the system of appointing Phanariote Greeks to the principalities of Moldavia and Wallachia was instituted. (See PHANARIOTES.)