did not recognise Jesus as the Messiah. In the later Judaism (as it shews itself in the Talmud), the conceptions of the M. are rich in singularities. It was believed that the true M., the son of David, would be preceded by another Messiah, a son of Joseph, or Ephraim, who should suffer death for men as a sin-offering. Century after century, the Jews have expected the former, and repeatedly have they risen and placed themselves under the standard of dreamers, fanatics, and impostors, who took to themselves the sacred name; as, for example, BAR-COCHBA (q. v.) in the 2d c.; one Moses in the Isle of Candia, in the 5th c.; one Julian in Palestine, in the 6th c.; several in Persia and Arabia in the 12th c.; and as late as the 18th c., Sabatai Zevi, in Aleppo. Even yet, the hope of a M. is not dead in the hearts of the strict Talmudistic Jews.

The crucial question of theology, however, is not the form in which the doctrine (so to speak) of the M. was held by the Jews. All rational students of Scripture, whether orthodox' or 'heterodox,' now admit that its growth was gradual, and that it acquired precision and definiteness of outline in the course of ages from its first rude phase, among the pastoral princes of the Syrian wilderness, down to that sublime, yet shadowy personality-the Man of Sorrows-that continually floats before the vision of the Younger Isaiah.' The grand question is: Was this doctrine essentially a Divine inspiration, an objective truth of God, or only a lofty conception of the religious soul? The strict rationalistic theologians maintain--and endeavour to prove by an analytic examination of the Gospels-that Jesus assumed the dignity of M., either to accommodate himself to a rooted conception of his countrymen, or partly because he had come to believe it himself-a conclusion, it is said, at which he might arrive quite honestly, since he felt that the truth which he taught was the real and only kingdom of God,' and that therefore he was justified in applying to himself all that was said (tropically) by the prophetic poets in old times concerning him who should usher in this golden age' of the world's faith. The mass of orthodox theologians, on the other hand, regarding the socalled Messianic prophecies of the Old Testament as positive, divinely suggested (perhaps, even on the part of their authors, conscious) predictions of Jesus Christ, repudiate the principle of accommodation, or even spiritual application, and try to shew that the Saviour accepted the Messianic prophecies as literally and exclusively applicable to him. The historico-spiritual school, represented in Germany by men like Neander, Rothe, Tholuck, &c., and in England, generally speaking, by the divines of the Broad Church' party, occupy a middle position between these two extremes: with the rationalists, they hold that the Old Testament doctrine of the M. was gradually developed, contains many human elements, and does not imply any knowledge of the historical Jesus on the part of those who announce it; with the orthodox,' on the other hand, they assert that the doctrine is the expression of a fact, not of a sentiment that Jesus of Nazareth was actually the Son of God, the appointed M., and that in him the so-called Messianic prophecies were fulfilled in a far higher sense than ever the prophets could have dreamed. It will thus be seen that the rationalists resolve the doctrine of the M. into a merely subjective religious idea; while the orthodox, and also the historicospiritual school of theologians, hold that the doctrine was the expression of a divine fact-the substance of a heavenly faith.

MESSI'NA, a city of Sicily, chief town of the province of same name, one of the most ancient and

most important cities of the island, is charmingly situated on the strait of M., encircled by a zone of abrupt conical rocks, and commands a view of Calabria on the continent. Pop. 94,133. The town is enclosed by old walls, and has several fine squares and wide lava-paved streets. The harbour, which is formed by a projecting tongue of land curved in the form of a sickle (whence its primitive name, Zancle-Gr. sickle-see MESSENIA), is about four miles in circumference, and can contain a thousand ships; it is defended by a citadel and six forts; the depth is sufficient to admit vessels of large size; and the quays are spacious. The trade of M., chiefly in silk, oil, wine, coral, fruits, linseed, fish, &c., although less extensive than formerly, is still an important source of wealth to Sicily. The chief imports are cotton and woollen manufactures, hardwares, and other articles of colonial produce. The damasks and satins of M. are excellent, and the fisheries important. M. has steam-boat communication with Naples, Marseille, and Malta. In the 15th c., M. was a renowned seat of learning; and in the 16th c., a famous school of painting was founded there by Pelidoro da Caravaggio. In modern times, it has undergone terrible vicissitudes, having been ruthlessly bombarded by the royal forces on several occasions during the war of independence in 1848.

MESSINA, STRAITS OF (Ital. Faro di Messina, Lat. Mamertinum fretum), between Italy and Sicily, are 22 miles in length, and vary from 24 to 10 miles in breadth. A strong current runs through the strait, which is of great depth. See SCYLLA AND CHARYBDIS.

ME'SSUAGE, the legal term used in English law to describe a dwelling-house and piece of land adjoining.

METACENTRE. See HYDROSTATICS.

METAL (in Heraldry). The field of the escutcheon and the charges which it bears may be of metal as well as of colour; and the two metals in use among heralds are gold and silver, known as or and argent. It is a rule of blazon that metal should not be placed on metal, or colour on colour.

METALLURGY is the art of extracting metals from their ores. The operations are partly mechanical and partly chemical. Those processes which depend principally on chemical reactions for their results have reference chiefly to the roasting and smelting of ores, and are described under the heads of the different metals. But there are certain preliminary operations of a mechanical kind which metallic ores undergo, such as crushing, jigging, washing, &c., which we shall describe here, as they are essentially the same for the ores of lead, copper, tin, zinc, and indeed most of the metals. (For IRON, see that head.)

Ores are first broken up with hammers into pieces of a convenient size for crushing or stamping. Waste material, such as pieces of rock, spar, &c., which always accompany ore, are as far as possible picked out by hand, and the ore itself arranged in sorts according to its purity. Various kinds of apparatus, such as riddles, sieves, &c., are then used for separating it into different sizes, in order to secure a uniform strain on the crushing machinery.

Figs. 1 and 2 represent one of the most approved forms of a crushing-mill. The ore is raised by means of small wagons, a, to the platform b, where it is ready to be supplied to the crushing. rollers r through the opening c. These rollers are mounted in a strong iron frame, held together by wrought-iron bars, and bolted to strong beams. Their distance apart is regulated by means of the lever d, to which a weight e is attached. The

End view of the crushing rollers, sieves, and bucket-wheel. between the rollers to widen. The crushed ore falls upon a series of sieves, f, which are made to vibrate. These have meshes increasing in fineness as they descend; and the upper two are so wide that pieces of ore too large to pass through them are conducted

Fig. 3.-Jigging Sieve.

the lower consists of the heavier and purer portions of the ore, which are now ready for the roasting furnace.

It will be apparent that in the bottom of the tub there must be a quantity of more or less valuable ore, which, from its fineness, has fallen through the sieve. This is called sludge or slime; and the minute particles of ore it contains are recovered either by simply forming an incline on the ground, and washing it with a current of water, or by using an inclined table, such as is shewn in fig. 4, called a sleeping-table. Ore which has been reduced to powder at the stamping-mill, as well as slime, is washed by this apparatus. The material is put into the chest a, which is placed in a sloping position, and is supplied with water on turning the stop-cock b. The current carries the contents of the chest through the opening at the bottom, and spreads it,

Side view of the crushing rollers, sieves, and bucket-wheel.

into the lower part of the bucket-wheel g, and raised again to the platform to be recrushed. The lower four sieves separate the remaining portion of the crushed ore into different degrees of fineness, which is collected in the pits h.

Instead of crushing-rollers, sometimes a stampingmill is used, especially for tin ores, which require to be reduced to a fine powder. The stamping-mill consists of a series of upright shafts with a weighty piece of iron at the bottom of each. They are raised by means of an axle with projecting cams, and then falling by their own weight, act like hammers.

After being crushed, the ore is washed and sifted on a jigging sieve. One of its simplest forms is shewn in fig. 3. The ore is placed on the table a, from which the sieve b is filled. It is then immersed in a tub of water c, and a jigging motion communi

Fig. 4. Sleeping Table.

with the aid of a series of stops, or small bits of wood c, over the surface of the table d. A stream of water is then kept flowing over the table till the earthy impurities are all carried down into the trough e, the pure particles of the ore remaining, by reason of their greater specific gravity, near the top of the table, whence they are removed to be smelted. Sometimes the table is suspended by chains, and receives a succession of blows at the top from a buffer, moved by cams on the same principle as the stamping-mill. This arrangement is found of great advantage in dressing very poor ores.

The variety of machinery and apparatus used in dressing ores is very great, and they pass under different names in different districts, but they are all very similar in principle to those we have described.

METALS, METALLOIDS. Although each metal is considered in a separate article, there are various points regarding the general physical and chemical characters of these bodies, and the method of classifying them, which require notice.

It is not easy to define a metal. All the elements are usually divided by chemists into two groupsviz., the non-metallic bodies or metalloids, and the metals; the list of non-metallic bodies containing all those elements in which the characteristic properties of the bodies popularly known as metals (such as silver, gold, iron, &c.) are wanting; these characteristic properties being their metallic lustre, their opacity, and their capacity of conducting heat and electricity. The non-metallic elements are 14 in number-viz., oxygen, hydrogen, nitrogen, sulphur, selenium, tellurium, phosphorus, chlorine, bromine, iodine, fluorine, carbon, boron, and silicon, of which five are gases, one a liquid, and the rest are solids at ordinary temperatures.

The division of the elements into these two great groups is, however, not based upon any definite scientific grounds, and it is still an open question whether some of the metalloids, as, for example, tellurium and silicon, should not be placed amongst

the metals. The non-metallic bodies or metalloids

being only remarkable as a group for their negative properties, require no special consideration, and we therefore proceed to notice the general properties of the metals.

The following are the most important of the physical properties of the metals.

1. All metals, unless when they are in a finely pulverised form, exhibit more or less of the characteristic lustre termed metallic. Two of the nonmetallic elements, iodine and carbon, in some forms, present also a metallic lustre. 2. All metals are good conductors of heat and electricity, although in very unequal degrees. 3. With the exception of mercury, all the metals are solid at ordinary temperatures. With the exception of gold, copper, calcium, and strontium, the metals are more or less white, with a tendency to blue or gray. Most of them have been obtained in crystals, and probably all of them are capable of crystallising under certain conditions. 4. Metals are remarkable for their opacity, and, with the exception of gold, do not transmit light, even when they are reduced to extremely thin leaves. 5. All the metals are fusible, although the temperatures at which they assume the fluid form are very different (see FUSING POINTS); and some of them, as mercury, arsenic, cadmium, zinc, &c., are also volatile. 6. Great weight, or a high specific gravity, is popularly but erroneously regarded as a characteristic of a metal; while platinum, osmium, and iridium (the heaviest bodies known in nature), are more than 20 times as heavy as water, lithium, potassium, and sodium are actually lighter than that fluid. 7. Great differences are observable in the hardness, brittleness, and tenacity of metals. While potassium and sodium may be kneaded with the finger, and lead may be marked by the fingernail, most of them possess a considerable degree of hardness. Antimony, arsenic, and bismuth are so brittle that they may be easily pulverised in a mortar; while others, as iron, gold, silver, and copper, require great force for their disintegration. Taking iron and lead as representing the two extremes of tenacity, it is found that an iron wire will bear a weight 26 times as heavy as a leaden wire of the same diameter. See DUCTILITY, MALLE

ABILITY. 8. It is a remarkable property of the metals, that none of them are capable of being dissolved without undergoing chemical change Sulphur, phosphorus, iodine, &c., may be dissolved, and after the evaporation of the solvent, may be re-obtained with all their original properties; but this is never the case with metals.

Amongst the chief chemical properties of metals we next notice:

Their strong affinities to certain of the nonmetallic elements. All the metals, without exception, combine with oxygen, sulphur, and chlorine, and often in several proportions, forming oxides, sulphides (formerly termed sulphurets), and chlorides. Many of them combine with bromine, iodine, and fluorine. The other compounds of this nature, excepting carbide (formerly carburet) of iron, or steel, and the hydrides of arsenic and antimony (commonly known as arseniuretted and antimoniuretted hydrogen), which are of importance in toxicology, may be passed over without notice.

The metallic oxides are, without exception, solid bodies, insoluble in water, and usually present a white or coloured earthy appearance. Hence the old name of metallic calx for these oxides.

Those oxides which are termed basic possess the property of directly uniting with the so-called oxyacids (such as sulphuric, nitric, carbonic, and silicic acid), and of forming a new chemical compound of the second order, termed a salt (q. v.).

The compounds of the metals with chlorine, iodine, bromine, and fluorine, such, for instance, as chloride of sodium, or common salt (CINa), are termed Haloid Salts (q. v.). The same metal may often combine both with chlorine and with oxygen in more than one proportion. For example, we have subchloride of mercury (Hg, Cl); suboxide of mercury (Hg, 0); chloride of mercury (HgCl); oxide of mercury (HgO). For the compounds of the metals with sulphur, see SULPHIDES OF THE METALS.

Metals enter into combination with one another when they are fused together, and such combinations are termed Alloys (q. v.), unless when mercury is one of the combining metals, in which case, the resulting compound is termed an amalgam. It is doubtful whether all alloys are true chemical compounds. Definite compounds of the metals with each other do, however, certainly exist, and are sometimes found native, as, for example, the crystallised silver and mercury compound represented by the formula AgHg,.

In consequence of their strong affinities for the metalloids, the metals are seldom found in a free or uncombined state, even in the inorganic kingdom, and never in animals or plants. The more common metals, in consequence of their strong affinity for oxygen and sulphur, are very rarely met with in the uncombined state; but some of those which are less abundant, such as gold, silver, and platinum, are found uncombined, in which case the terms native and virgin are applied to them; and other metals, as mercury and copper, occur both in a free and in a combined state. Many native alloys are found, but the ordinary sources of the metals are oxides, sulphides, chlorides, and carbonates, sulphates, and other salts. These are termed the ores of the metals. The methods of obtaining the metals from their various ores fall under the head of METALLURGY.

Various classifications of the metals have been

suggested by different chemists. The following is probably one of the most convenient:

I.-The Light Metals, subdivided into

1. The metals of the alkalies-viz., potassium, sodium, cæsium, rubidium, lithium.

deposits rearranged themselves as they are found in the Metamorphic Rocks.

The description of the various Metamorphic Rocks will be found under their different names, viz., GNEISS, QUARTZITE, MICA-SCHIST, CLAY-SLATE, and MARBLE

METAMORPHOSIS (Gr. change of form) denoted, in the mythology of the ancients, those transformations of human beings into beasts, stones, trees, and even into fire, water, &c., in fables of which that mythology abounded. The origin and significance of such fables it is often impossible to determine. Some of them probably originated in observation of the wonderful transformations of nature; some in a misapprehension of the metaphors employed by the older poets; and some, perhaps, in mere superstition and love of the marvellous. The wild imagination of the Orientals filled their mythologies with metamorphoses in the greatest number; and the classic mythology approaches to them in this respect. They were the theme of some of the poets and other Greek authors of the Alexandrine period, and of Ovid among the Latin classics. The medieval literature of Europe, especially of Germany, in its fairy tales and other forms of folk-lore, is also wonderfully rich in metamorphoses.

METAMORPHOSIS OF ANIMALS. This term is applied to changes which certain animals undergo after their escape from the envelope of the egg, and which are of such a nature as essentially to alter the general form or the mode of life of the

individual.

The most remarkable metamorphoses occur in the Batrachians, Crustaceans, Insects, and Tape-worms, and are briefly noticed in the articles on those classes of animals. For an excellent general account of the metamorphoses of animals, the reader is referred to a series of articles by De Quatrefages in the Revue des Deux Mondes for 1853.

METAMORPHOSIS OF ORGANS, in Botany, a subject of so much importance, that it has been exalted to the rank of a distinct branch of botanical science, under the name of Morphology or Vegetable Morphology. Attention to it is essential to a philosophical study of botany; yet it may almost be said that nothing was known either of its facts or its laws, till the poet Goethe proclaimed them to the world in his treatise entitled Die Metamorphose der Pflanzen, in 1790. Linnæus had, indeed, called attention to the development of organs, and the changes which they undergo, and had made this the subject of a thesis entitled Prolepsis Plantarum in 1760; but, in a manner very unusual with him, he mixed up with his observations and philosophical speculations certain fanciful suppositions, the falsehood of which soon becoming apparent, caused all the rest to be neglected. Wolff afterwards extricated the true from the fanciful in the views of Linnæus, and gave them greater completeness; but he introduced the subject only incidentally in a paper on comparative anatomy, which failed to attract the attention of botanists, and probably had never been seen by Goethe, whose discovery, apparently altogether original, is one of the finest instances on record of acute observation combined with philosophical generalisation.

axis being modified leaves. The proof of this consists very much in the gradual transition of one organ into another, manifest in some plants, although not in others; as of leaves into bracts, one of the most frequently gradual transitions; of leaves into sepals, as seen in the leaf-like sepals of many roses; of sepals into petals, as seen in the petal-like sepals of lilies, crocuses, &c.; of petals into stamens, as seen in water-lilies; and even of stamens into pistils, often exemplified in the common house-leek. The proof is confirmed and completed by observation of the monstrosities which occur in plants, particularly in the frequent return of some part of the flower to its original type, the leaf, and in the conversion of one part of the flower into another, which is often the result of cultivation, and is particularly illustrated in double flowers, the increase of the number of petals being the result of the conversion of stamens into petals.

A flower-bud being a modified leaf-bud (see BUD), and a flower therefore the development of a modified leaf-bud, the parts of a flower correspond in their arrangement with the leaves on a branch. But peculiar laws govern the development of organs in each species of plant. Thus, the leaves in one are opposite; in another, alternate; in another, whorled; all depending on the law which governs the growth of the axis in relation to the development of leaves, which is very constant in each species; and in like whorls around an abbreviated terminal portion of manner the parts of the flower are developed in the axis, the energies of the plant being here directed to the reproduction of the species, and not to the increase or growth of the individual. The fruit itself, being formed from the pistil, is to be regarded as formed of modified leaves. Goethe truly says: The pod is a leaf which is folded up and grown together at its edges, and the capsule consists of several leaves grown together; and the compound fruit is composed of several leaves united round a common centre, their sides being opened so as to form a communication between them, and their edges adhering together.'

The metamorphosis of organs has been investigated with great diligence and success, and beautifully elucidated by Miquel, Lindley, Schleiden, and other botanists.

METAMORPHOSIS OF TISSUE. See TISSUE. METAPHOR (Gr. metaphora, a transference), a figure of speech, by means of which one thing is put for another which it only resembles. Thus, the Psalmist speaks of God's law as being a light to his feet and a lamp to his path.' The metaphor is therefore a kind of comparison, in which the speaker or writer, casting aside the circumlocution of the ordinary similitude, seeks to attain his end at once, by boldly identifying his illustration with the thing illustrated. It is thus of necessity, when well conceived and expressed, graphic and striking in the highest degree, and has been a favourite figure with poets and orators, and the makers of proverbs, in all ages. Even in ordinary language the meanings of words are in great part metaphors; as when we speak of an acute intellect, or a bold promontory.