Chapter 50

England and south Russia. The country is also covered with thick diluvial and alluvial deposits containing gold. However, all the mining is now on the decline.

Population.--The Russian population has rapidly increased since the fertile valleys belonging to the imperial family have been thrown open to settlement, and it has been estimated that in 1908 the population of the region (Biysk, Barnaul and Kuznetsk districts) reached about 800,000. Their chief occupations are agriculture (about 3,500,000 acres under culture), cattle-breeding, bee-keeping, mining, gathering of cedar-nuts and hunting. All this produce is exported partly to Tomsk and partly to Kobdo in Mongolia. The natives may represent a population of about 45,000. They are Altaians in the west and Telenghites or Teleuts in the east, with a few Kalmucks and Tatars. Although all are called Kalmucks by the Russians, they speak a Turkish language. Both the Telenghites and the Altaians are Shamanists in religion, but many of the former are already quite Russified. The virgin forests of the Kuznetsk Ala-tau -- the Chern, or Black Forest of the Russians -- are peopled by Tatars, who live in very small settlements, sometimes of the Russian type, but mostly in wooden yurts or huts of the Mongolian fashion. They can hardly keep any cattle, and lead the precarious life of forest-dwellers, living upon various wild roots when there is no grain in the spring. Hunting and fishing are resorted to, and the skins and furs are tanned.

Towns.--The capital of the Altai region is Barnaul, the centre of the mining administration and an animated commercial town; Biysk is the commercial centre; Kuznetsk, Ust-Kamenogorsk, and the mining towns of Kolyvan, Zmeinogorsk, Riddersk and Salairsk are the next largest places.

AUTHORITIES. -- P. Semenov and G. N. Potanin, in supplementary vol. of Russian ed. of Ritter's Asien (1877); Ledebour, Reise durch das Altaigebirge (1829-1830); P. Chikhatchev, Voyage scientifique dans l'Altai oriental (1845); Gebler, Ubersicht des katunischen Gebirges (1837); G. von Helmersen, Reise nach dem Altai (St Petersburg, 1848); T. W. Atkinson, Oriental and Western Siberia (1838); and Cotta, Der Altai (1871), are still worth consulting. Of modern works see Adrianov, ``Journey to the Altai,'' in Zaeiski Russ. Geogr. Soc. xi.; Yadrintsev, ``Journey in West Siberia,'' in Zapiski West Sib. Geogr. Soc. ii.; Golubev, Altai (1890, Russian); Schmurlo, ``Passes in S. Altai'' (Sailughem), in Izvestia Russ. Geogr. Soc. (1898), xxxiv. 5; V. Saposhnikov, various articles in same periodical (1897), xxxiii. and (1899) xxxv., and, by the same, Katun i yeya Istoka (Tomsk, 1901); S. Turner, Siberia (1905); Deniker, on Kozlov's explorations, in La Geographie (1901, pp. 41, &c.); and P. Ignatov, in Izvestia Russ. Geog. Soc. (1902, No. 2). (P. A. K.; J. T. BE.)

1 Mr S. Turner estimates the culminating peak of Mt. Byelukha at 14,800 ft., but to Willer's Peak, a little to the N. W. of Byelukha, he assigns an altitude of 17,800 ft. (p. 205 of Siberia.)

ALTAMURA, a town of Apulia, Italy, in the province of Bari, 28 m. S.S.W. of the town of that name, and 56 m. by rail via Gioia del Colle. Pop. (1901) 22,729. It possesses a fine Romanesque cathedral begun in 1232 and restored in 1330 and 1531, the portal being especially remarkable. It is one of the four Palatine churches of Apulia. The surrounding territory is fertile. The medieval walls, erected by the emperor Frederick II., rest upon the walls of an ancient city of unknown name. These early walls are of rough blocks of stone without mortar. Ancient tombs with fragments of vases have also been found, and there are cases which have been used as primitive tombs or dwellings, and a group of some fifty tumuli near Altamura.

ALTAR (Lat. altare, from altus, high; some ancient etymological guesses are recorded by St Isidore of Seville in Etymologiae xv. 4), strictly a base or pedestal used for supplication and sacrifice to gods or to deified heroes. The necessity for such sacrificial furniture has been felt in most religions, and consequently we find its use widespread among races and nations which have no mutual connexion.

Mesopotamia. -- Altars are found from the earliest times in the remains of Babylonian cities; the oldest are square erections of sun-dried bricks. In Assyrian mounds limestone and alabaster are the chief material. They are of varying form; an altar shown in a relief at Khorsabad is ornamented with stepped battlements, which are the equivalent of the familiar ``altarhorns'' in Hebrew ritual. An altar also from Khorsabad (now in the British Museum) has a circular table and a solid base triangular on plan, with pilasters ornamented with animals' paws at the angles. A third variety, of which an 8th century B.C. example from Nimrod exists in the British Museum, is a rectangular block ornamented at the ends by cylindrical rolls. These altars are in height from 2 to 3 ft. According to Herodotus (i. 183) the great altars of Babylonia were made of gold.

Egypt. -- In Egypt altars took the form of a truncated cone or of a cubical block of polished granite or of basalt, with one or more basin-like depressions in the upper surface for receiving fluid libations. These had channels whereby fluids poured into the receptacles could be drained off. The surface was plain, inscribed with dedicatory or other legends, or adorned with symbolical carving.

Palestine. -- Recent excavations, especially at Gezer, have shown that the earliest altars, or rather sacrifice hearths, in Palestine were circular spaces marked out by small stones set on end. At Gezer a pre-Semitic place of worship was found in which three such hearths stood together, and drained into a cave which may reasonably be supposed to have been regarded as the residence of the divinity. These circular hearths persisted into the Canaanite period, but were ultimately superseded by the Semitic developments. To the primitive nomadic Semite the presence of the divinity was indicated by springs, shady trees, remarkable rocks and other landmarks; and from this earliest conception grew the theory that a numen might be induced to take up an abode in an artificial heap of stones, or a pillar set upright for the purpose. The blood of the victim was poured over the stone as an offering to the divinity dwelling within it; and from this conception of the stone arose the further and final view, that the stone was a table on which the victim was to be burned.

Very few specimens of early Palestinian altars remain. The megalithic structures common in the Hauran and Moab may be entirely sepulchral. At Gezer no definite altar was discovered in the great High Place; though it is possible that a bank of intensely hard compact earth, in which were embedded a large number of human skulls, took its place. A very remarkable altar, at present unique, was found at Taanach by the Austrian excavators. It is pyramidal in shape, and the surface is ornamented with human-headed animals in relief. This, like the earliest Babylonian altars, is of baked earth.

The Old Testament conception of the altar varies with the stage of religious development. In the pre-Deuteronomic period altars are erected in any place where there had appeared to be a manifestation of deity, or under any circumstance in which the aid of deity was invoked; not by heretical individuals, but by the acknowledged religious leaders, such as Noah at Ararat, Abraham at Shechem, Bethel &c., Isaac at Beersheba, Jacob at Bethel, Moses at Rephidim, Joshua at Ebal, Gideon at Ophrah, Samuel at Raman, Elijah at Carmel, and others. These primitive altars were of the simplest possible description -- in fact they were required to be so by the regulation affecting them, preserved in Exodus xx. 24, which prescribes that in every place where Yahweh records his name an altar of earth or of unhewn stone, without steps or other extraneous ornamentation, shall be erected.

The priestly regulations affecting altars are of a very elaborate nature, and are framed with a single eye to the essential theory of later Hebrew worship -- the centralization of all worship at one shrine. These recognize two altars, which by the authors of this portion of the Pentateuch are placed from the first in the tabernacle in the wilderness -- a theory which is inconsistent with the other evidences of the nature of the earlier Hebrew worship, to which we have just alluded.

The first of these altars is that for burnt-offering. This altar was in the centre of the court of the tabernacle, of acacia wood, 3 cubits high and 5 square. It was covered with copper, was provided with ``horns'' at the corners (like those of Assyria), hollow in the middle, and with rings on the sides into which the staves for its transportation could be run (Ex. xxvii. 1-8). The altar of the Solomonic temple is on similar lines, but much larger. It is now generally recognized that the description of the tabernacle altar is intended to provide a precedent for this vast structure, which would otherwise be inconsistent with the traditional view of the simple Hebrew altars. In the second temple a new altar was built after the fashion of the former (1 Macc. iv. 47) of ``whole stones from the mountain.'' In Herod's temple the altar was again built after the same model. It is described by Josephus (v. 5. 6) as 15 cubits high and 50 cubits square, with angle horns, and with an ``insensible acclivity'' leading up to it (a device to evade the pre-Deutero- nomic regulation about steps). It was made without any use of iron, and no iron tool was ever allowed to touch it. The blood

and refuse were discharged through a drain into the brook Kedron; this drain probably still remains, in the Bir el-Arwah, under the ``Dome of the Rock'' in the mosque which covers the site of the temple.

The second altar was the altar of incense, which was in the holy place of the tabernacle. It was of similar construction to the altar of burnt-offering, but smaller, being 2 cubits high and 1 cubit square (Ex. xxx. 1-5). It was overlaid with gold. Solomon's altar of incense (1 K. vi. 20) is referred to in a problematical passage from which it would appear to have been of cedar. But the authenticity of the passages describing the altar of incense in the tabernacle, and the historicity of the corresponding altar in Solomon's temple, are matters of keen dispute among critics. The incense altar in the second temple was removed by Antiochus Epiphanes (1 Macc. i. 21) and restored by Judas Maccabaeus (1 Macc. iv. 49). That in the temple of Herod is referred to in Luke i. 11.

The ritual uses of these altars are sufficiently explained by their names. On the first was a fire continually burning, in which the burnt-offerings were consumed. On the second an offering of incense was made twice a day.

In the pre-Deuteronomic passage, Exodus xxi. 14, the use of the altar as an asylum is postulated, though denied to the wilful murderer. This is a survival of the ancient belief that the deity resided in the pillar or stone-heap, and that the fugitive was placing himself under the protection of the local numen by seeking sanctuary. From 1 Kings i. 50 it would appear that the suppliant caught hold of the altar-horns (compare 1 Kings ii. 28), as though special protective virtue resided in this important though obscure part of the structure.

Greece and Rome. -- According to the difference in the service for which they were employed, altars fell into two classes. Those of the first class were pedestals, so small and low that the suppliant could kneel upon them; these stood inside the temples, in front of the sacred image. The second class consisted of larger tables destined for burnt sacrifice; these were placed in the open air, and, if connected with a temple, in front of the entrance. Possibly altars of the former class were in historical times substitutes for, and rendered the same service as, the bases of the sacred images within the temples in earlier ages. In this case the altar of Apollo at Delphi, upon which on the Greek vases Neoptolemus is frequently represented as taking refuge from Orestes, might be regarded as the pedestal of an invisible image of the god, and as fulfilling the same function as did the base of the actual image of Athene in Troy, towards which Cassandra fled from Ajax. The second class of altars, called bomoi by the Greeks and altaria by the Romans, appears to have originated in temporary constructions such as heaps of earth, turf or stone, made for kindling a sacrificial fire as occasion required. But sacrifices to earth divinities were made on the earth itself, and those to the infernal deities in sunk hollows (Odyss. x. 25; Festus s. v. Altaria). The note of Eustathius (Odyss. xii. 252) perhaps indicates some customs reminiscent of a primitive antiquity in which the sacrifice was made without an altar at all. He says apobomia tina iera on ouk epi bomou o kathagis mos all' epi edafous -- ``some holy places away from altars, whose offering is made not on an altar but on the floor.'' Pausanias (vi. 20. 7) speaks of an altar at Olympia made of unbaked bricks. In some primitive holy shrines the bones and ashes of the victims sacrificed were allowed to accumulate, and upon this new fires were kindled. Altars so raised were, like most religious survivals, considered as endowed with particular sanctity; the most remarkable recorded instances of such are the altars of Hera at Samos, and of Pan at Olympia (Paus. v. 14. 6; v. 15. 5), of Heracles at Thebes (Paus. ix. 11. 7), and of Zeus at Olympia (Paus. v. 13. 5). The last-mentioned stood on a platform (prothusis) measuring 125 ft. in circumference, and led up to by steps, the altar itself being 22 ft. high. Women were excluded from the platform. Where hecatombs were sacrificed, the prothusis necessarily assumed colossal proportions, as in the case of the altar at Parion, where it measured on each side 600 ft. The altar of Apollo at Delos (o keratinos bomos) was made of the horns of goats believed to have been slain by Diana; while at Miletus was an altar composed of the blood of victims sacrificed (Paus. v. 13. 6). The altar at Phorae in Achaea was of unhewn stones (Paus. vii. 22. 3). The altar used at the festival in honour of Daedalus on Mt. Cithaeron was of wood, and was consumed along with the sacrifice (Paus. ix. 3. 4). Others of bronze are mentioned. But these were exceptional, the usual material of an altar was marble, and its form, both among the Greeks and Romans, was either square or round; polygonal altars, of which examples still exist, being exceptions. When sculptured decorations were added they frequently took the form of imitations of the actual festoons with which it was usual to ornament altars, or of symbols, such as crania and horns of oxen, referring to the victims sacrificed. As a rule, the altars which existed apart from temples bore the name of the person by whom they were dedicated and the names of the deities in whose service they were, or, if not the name, some obvious representation of the deity. Such, for example, is the purpose of the figures of the Muses on an altar dedicated to them, now to be seen in the British Museum. An altar was retained for the service of one particular god, except where through local tradition two or more deities had become intimately associated, as in the case of the altar at Olympia to Artemis and Alpheus jointly, or that of Poseidon and Erechtheus in the Erechtheum at Athens. The most remarkable instance of multiple dedication was, however, at Oropus, where the altar was divided into five parts, one dedicated to Heracles, Zeus and Paean Apollo, a second to heroes and their wives, a third to Hestia, Hermes, Amphiaraus and the children of Amphilochus, a fourth to Aphrodite Panacea, Jason, Health, and Healing Athene, and the fifth to the Nymphs, Pan, and the rivers Archelous and Cephissus (Paus. i. 34. 2). Such deities were styled sbmbomoi, each having a separate part of the altar (Paus. i. 34. 2). Other terms are agonioi, or omobomioi. Deities of an inferior order, who were conceived as working together -- e.g. the wind gods -- had an altar in common. In the same way, the ``unknown gods'' were regarded as a unit, and had in Athens and at Olympia one altar for all (Paus. i. 1. 4; v. 14. 5; cf. Acts of Apostles, xvii. 18). An altar to all the gods is mentioned by Aeschylus (Suppl. 222). Among the exceptional classes of altars are also to be mentioned those on which fire could not be kindled (bomoi apuroi), and those which were kept free from blood (bomoi anaiaaktoi), of which in both respects the altar of Zeus Hypatos at Athens was an example. The lstia was a round altar; the eschara, one employed apparently for sacrifice to inferior deities or heroes (but lschara Toibou, Aesch. Pers. 205). In Rome an altar erected in front of a statue of a god was always required to be lower than the statue itself (Vitruvius iv. 9). Altars were always places of refuge, and even criminals and slaves were there safe, violence offered to them being insults to the gods whose suppliants the refugees were for the time being. They were also taken hold of by the Greeks when making their most solemn oaths.

Ancient America. -- As a single specimen of an altar, wholly unrelated to any of the foregoing, we may cite the ancient Mexican example described by W. Bullock (Six Months in Mexico, London, 1824, p. 335). This was cylindrical, 25 ft. in circumference, with sculpture representing the conquests of the national warriors in fifteen different groups round the side.

Portable altars and tables of offerings were used in pre-Christian as well as in Christian ritual. One such was discovered in the Gezer excavations, dating about 200 B.C. It was a slab of polished limestone about 6 in. square with five cups in its upper surface. Another from the same place was a small cubical block of limestone bearing a dedication to Heracles. They have also been found in Assyria. Pocket altars are still used in some forms of worship in India. See the Journal of the Royal Asiatic Society, 1852, p. 71.

1 Bullock also says (p. 354) that the altar in the church of the indian village of S. Miguel de los Ranchos which he visited was ``of the same nature as those in use before the introduction of Christianity.''

ALTARS IN THE CHRISTIAN CHURCH I. The Early Church. -- The altar is spoken of by the early Greek and Latin ecclesiastical writers under a variety of names: -- trapefa, the principal name in the Greek fathers and the liturgies; thusiasterion (rarer; used in the Septuagint for Hebrew altars); ilasterion; bomos (usually avoided, as it is a word with heathen associations); mensa Domini; ara (avoided like bomos, and for the same reason); and, most regularly, altare. After the 4th century other names or expressions come into use, such as mensa tremenda, series corporis et sanguinis Christi.

The earliest Christians had no altars, and were taunted by the pagans for this. It is admitted by Origen in his reply to Celsus (p. 389), who has charged the Christians with being a secret society ``because they forbid to build temples, to raise altars.'' ``The altars,'' says Origen, ``are the heart of every Christian.'' The same appears from a passage in Lactantius, De Origine Erroris, ii. 2. We gather from these passages that down to about A.D. 250, or perhaps a little later, the communion was administered on a movable wooden table. In the Catacombs, the arcosolia or bench-like tombs are said (though the statement is doubtful) to have been used to serve this purpose. The earliest church altars were certainly made of wood; and it would appear from a passage in William of Malmesbury (De Gest. Pontif. Angl. iii. 14) that English altars were of wood down to the middle of the 11th century, at least in the diocese of Worcester.

The cessation of persecution, and consequent gradual elaboration of church furniture and ritual, led to the employment of more costly materials for the altar as for the other fittings of ecclesiastical buildings. Already in the 4th century we find reference to stone altars in the writings of Gregory ot Nyssa. In 517 the council of Epaone in Burgundy forbade any but stone pillars to be consecrated with chrism; but of course the decrees of this provincial council would not necessarily be received throughout the church.

Pope Felix I. (A.D. 269-274) decreed that ``mass should be celebrated above the tombs of martyrs'' -- an observance probably suggested by the passage in Revelation vi. 9, ``I saw under the altar the souls of them that were slain for the word of God.'' This practice developed into the medieval rule that no altar can be consecrated unless it contain a relic or relics.

The form of the altar was originally table-shaped, consisting of a plane surface supported by columns. There were usually four, but examples with one, two and five columns are also recorded. But the development of the relic-custom led to the adoption of another form, the square box shape of an ``altar- tomb.'' Transitional examples, combining the box with the earlier table shape, are found dating about 450. Mention is made occasionally of silver and gold altaus in the 5th to the 8th centuries. This means no doubt that gold and silver were copiously used in its decoration. Such an altar still remains in Sant' Ambrogio at Milan, dating from the 9th century (see fig. 1).

II. The Medieval Church. -- It will be convenient now to pass to the fully-developed altar of the Western Church with its accessories, though the rudiments of most of the additional details are traceable in the earlier period.

In the Roman Catholic Church, which preserves in this respect the tradition that had become established during the middle ages, the component parts of a fixed altar in the liturgical sense are the table (mensa), or super-altar, consisting of a stone slab; the support (stipes), consisting either of a solid mass or of four or more columns; the sepulchrum, or altar-cavity, a small chamber for the reception of the relics of martyrs. The support, in the technical sense, must be of stone solidly joined to the table; but, if this support consist of columns, the intervals may be filled with other materials, e.g. brick or cement. The altar- slab or ``table'' alone is consecrated, and in sign of this are cut in its upper surface five Greek crosses, one in the centre and one in each corner. These crosses must have been anointed by the bishop with chrism in the ritual of consecration before the altar can be used. Crosses appear on the portable altar buried with St Cuthbert (A.D. 687), but the history of the origin and development of this practice is not fully worked out.

According to the Caeromoniale (i. 12. 13) a canopy (balda chinum) should be suspended over the altar; this should be square, and of sufficient size to cover the altar and the predella on which the officiating priest stands. This baldachin, called liturgically the ciborium, is sometimes hung from the roof by chains in such a way that it can be lowered or raised; sometimes it is fixed to the wall or reredos; sometimes it is a solid structure of wood covered with metal or of marble supported on four columns. The latter form is, however, usual only in large churches, more especially of the basilica type, e.g. St Peter's at Rome or the Roman Catholic cathedral at Westminster. The origin of the ciborium is not certain, but it is represented in a mosaic at Thessalonica of a date not later than A.D. 500. Even at the present day, in spite of a decree of the Congregation of Rites (27th of May 1697) ordering it to be placed over all altars, it is -- even at Rome itself -- usually only found over the high altar and the altar of the Blessed Sacrament.

Multiplication of altars is another medieval characteristic. This also is probably a result of the edict of Pope Felix already mentioned. In a vault where more than one martyr was buried an altar might be erected for each. It is in the 6th century that we begin to find traces of the multiplication of altars. In the church of St Gall, Switzerland, in the 9th century there were seventeen. In the modern Latin Church almost every large church contains several altars -- dedicated to certain saints, in private side chapels, established for masses for the repose of the founder's soul, &c. Archbishop Wuifred in 816 ordered that beside every altar there should be an inscription recording its dedication. This regulation fell into abeyance after the 12th century, and such inscriptions are very rare. One remains mutilated at Deerhurst (Archaeologia, vol. 1. p. 69).

Where there is in a cathedral or church more than one altar, the principal one is called a ``high altar.'' Where there is a second high altar, it is generally at the end of the choir or chancel. In monastic churches (e.g. formerly at St Albans) it sometimes stands at the end of the nave close to the choir screen.

Beside the altar was a drain (piscina) for pouring away the water in which the communion vessels were rinsed. This seems originally to have been under the altar, as it is still in the Eastern Church.

That the primitive communion table was covered with a communion-cloth is highly probable, and is mentioned by Optatus (c. A.D. 370), bishop of Alilevis. This had developed by the 14th or 15th century into a cerecloth, or waxed cloth, on the table itself; and three linen coverings one above the other, two of about the size of the table and one rather wider than the altar, and long enough to hang down at each end. Five crosses are worked upon it, four in the corners and one in the middle, and there is an embroidered edging.1 In front was often a hanging panel of embroidered cloth (the frontal; but frontals of wood, ornamented with carving or enamel, &c., are also to be found). These embroidered frontals are changeable, so that the principal colour in the pattern can accord with the liturgical colour of the day. Speaking broadly, red is the colour for feasts of martyrs, white for virgins, violet for penitential seasons, &c.; no less than sixty-three different uses differing in details have been enumerated. A similar panel of needlework (the dossal) is suspended behind the altar.

Portable altars have been used on occasion since the time of Bede. They are small slabs of hard stone, just large enough for the chalice and paten. They are consecrated and marked with the five incised crosses in the same way as the fixed altar, but they may be placed upon a support of any suitable material, whether wood or stone. They are used on a journey in a heretical or heathen country, or in private chapels. In the inventory of the field apparel of Henry, earl of Northumberland, A.D. 1513, is included ``A coffer wyth ij liddes to serue for an Awter and ned be'' (Archaeologia, xxvi. 403).

On the altar are placed a cross and candlesticks -- six in number, and seven when a bishop celebrates in his cathedral; and over it is suspended or fixed a tabernacle or receptacle for the reservation of the Sacrament.

III. Post-Reformation Altars. -- At the Reformation the altars in churches were looked upon as symbols of the unreformed doctrine, especially where the struggle lay between the Catholics and the Calvinists, who on this point were much more radical revolutionaries than the Lutherans. In England the name ``altar''2 was retained in the Communion Office in English, printed in 1549, and in the complete English Prayer-book of the following year, known to students as the First Book of Edward VI. But orders were given soon after that the altars should be destroyed, and replaced by movable wooden tables; while from the revised Prayer book of 1552 the word ``altar'' was carefully expunged, ``God's board'' or ``the table'' being substituted. The short reign of Mary produced a temporary reaction, but the work of reformation was resumed on the accession of Elizabeth.

The name ``altar'' has been all along retained in the Coronation Office of the kings of England, where it occurs frequently. It was also recognized in the canons of 1640, but with the reservation that ``it was an altar in the sense in which the primitive church called it an altar and in no other.'' In the same canons the rule for the position of the communion tables, which has been since regularly followed throughout the Church of England, was formulated. In the primitive church the altars seem to have been so placed that, like those of the Hebrews, they could be surrounded on all sides by the worshippers. The chair of the bishop or celebrant was on their east side, and the assistant clergy were ranged on each side of him. But in the middle ages the altars were placed against the east wall of the churches, or else against a reredos erected at the east side of the altar, so as to prevent all access to the table from that side; the celebrant was thus brought round to the west side and caused to stand between the people and the altar. On the north and south sides there were often curtains. When tables were substituted for altars in the English churches, these were not merely movable, but at the administration of the Lord's Supper were actually moved into the body of the church, and placed table-wise -- that is, with the long sides turned to the north and south, and the narrow ends to the east and west, -- the officiating clergyman standing at the north side. In the time of Archbishop Laud, however, the present practice of the Church of England was introduced. The communion table, though still of wood and movable, is, as a matter of fact, never moved; it is placed altar-wise -- that is, with its longer axis running north and south, and close against the east wall. Often there is a reredos behind it; it is also fenced in by rails to preserve it from profanation of various kinds.

In 1841 the ancient church of the Holy Sepulchre at Cambridge was robbed of most of its interest by a calamitous ``restoration'' carried out under the superintendence and partly at the charge of the Camden Society. On this occasion a stone altar, consisting of a flat slab resting upon three other upright slabs, was presented to the parish, and was set up in the church at the east wall of the chancel. This was brought to the notice of the Court of Arches in 1845, and Sir H. Jenner Fust (Faulkner v. Lichfield and Stearn) ordered it to be removed, on the ground that a stone structure so weighty that it could not be carried about, and seeming to be a mass of solid masonry, was not a communion-table in the sense recognized by the Church of England.

BIBLIOGRAPHY. -- For altars in the ancient East see M. Jastrow, Religion of Assyria anid Babylonia; Perrot and Chipiez, Art in Chaldea (i. 143, 255); Sir i. Gardiner Wilkinson, A Second Series of the Monners and Customs of the Ancient Egyptians, ii. 387; Benzinger's and Nowack's works on Hebraische Archaologie. For classical altars, much information can be obtained from the notes in J. G. Frazer's Pausaniae. See also Schomann, Griechische Alterthumer, vol. ii.; the volume on ``Gottesdienstliche Altcrthumer'' in Hermann's Lehrbuch der griechischen Antiquitaten. On domestic altars and worship see Petersen, Hausgottesdienst der Griechen (Cassel, 1851). On plural dedications consult Maurer, De aribus graecorum pluribus deis in commune positis (Darmstadt, 1885). For Christian altars, reference is best made to the articles on the subject in the dictionaries of Christian and liturgical antiquities of Migne, Martigny, Smith and Cheetham, and Pugin, where practically all the available information is collected. See also Ciampinus, Vetera Monumenta (Rome, 1747), where numerous illustrations of altars are to be found; Martune, De antiquis Ecclesiae ritibus, iii. vi. (Rouen, 1700); Voigt, Thyslasteriologia sive de altaribus veterum Christianorum (Hamburg, 1709); and the liturgical works of Bona. Many articles on various sections of the subject have appeared in the journals of archaeoloeical societies; we may mention Nesbitt on the churches of Rome earlier than 1150 (Archaeologia, xl. p. 210), Didron, ``L'Autel chretien'' (Annales archeologiques, iv. p. 238), and a paper by Texier on enamelled altars in the same volume. (R. A. S. M.)

1 In the Eastern Church four small pieces of cloth marked with the names of the Evangelists are placed on the four corners of the altar, and covered with three cloths, the uppermost (the corporal) being of smaller size.

2 Except in one place where the term used is ``God's Board.''

ALTDORF, the capital of the Swiss canton of Uri. It is built at a height of 1516 ft. above sea-level, a little above the right bank of the Reuss, not far above the point where this river is joined on the right by the Schachen torrent. In 1900 the population was 3117, all Romanists and German-speaking. Altdorf is 34 m. from Lucerne by the St Gotthard railway and 22 m. from Goeschenen. Its port on the Lake of Lucerne, Fluelon, is 2 m. distant. There is a stately parish church, while above the little town is the oldest Capuchin convent in Switzerland (1581). Altdorf is best known as the place where, according to the legend, William Tell shot the apple from his son's head. This act by tradition happened on the market-place, where in 1895, at the foot of an old tower (with rude frescoes commemorating the feat), there was set up a fine bronze statue (by Richard Kissling of Zurich) of Tell and his son. In 1899 a theatre was opened close to the town for the sole purpose of performing Schiller's play of Wilhelm Tell. The same year a new carriage-road was opened from Altdorf through the Schachen valley and over the Klausen Pass (6404 ft.) to the village of Linththal (30 m.) and so to Glarus. One and a half mile from Altdorf by the Klausen road is the village of Burglen, where by tradition Tell was born; while he is also said to have lost his life, while saving that of a child, in the Schachen torrent that flows past the village. On the left bank of the Reuss, immediately opposite Altdorf, is Attinghausen, where the ruined castle (which belonged to one of the real founders of the Swiss Confederation) now houses the cantonal museum of antiquities. (W. A. B. C.)

ALTDORFER, ALBRECHT (N 1480-1538), German painter and engraver, was born at Regensburg (Ratisbon), where in 1505 he was enrolled a burgher, and described as ``twenty-five years old.'' Soon afterwards he is known to have been prosperous, and as city architect he erected fortifications and a public slaughter-house. Altdorfer has been called the ``Giorgione of the North.,' His paintings are remarkable for minute and careful finish, and for close study of nature. The most important of them are to be found in the Pinakothek at Munich. A representation of the battle of Arbela (1529), included in that collection, is usually considered his chief work. His engravings on wood and copper are very numerous, and rank next to those of Albrecht Durer. The most important collection is at the Bedin museum. Albrecht's brother, Erhard Altdorfer, was also a painter and engraver, and a pupil of Lucas Cranach.

ALTEN, SIR CHARLES [Karl] (1764-1840), Hanoverian and British soldier, son of Baron Alten, a member of an old Hanoverian family, entered the service of the elector as a page at the age of twelve. In 1781 he received a commission in the Hanoverian guards, and as a captain took part in the campaigns of 1793- 1795 in the Low Countries, distinguishing himself particularly on the Lys in command of light infantry. In 1803 the Hanoverian army was disbanded, and Alten took service with the King's German Legion in British pay. In command of the light infantry of this famous corps he took part with Lord Cathcart in the Hanoverian expedition of 1805 and in the siege of Copenhagen in 1807, and was with Moore in Sweden and Spain, as well as in the disastrous Walcheren expedition. He was soon employed once more in the Peninsula, and at Albuera commanded a brigade. In April 1813 Wellington placed him at the head of the famous ``Light Division'' (43rd, 52nd, 95th, and Cacadores), in which post he worthily continued the records of Moore and Robert Craufurd at Nivelle, Nive, Orthez and

Toulouse. His officers presented him with a sword of honour as a token of their esteem. In 1815 Alten commanded Wellington's 3rd division and was severely wounded at Waterloo. His conduct won for him the rank of Count von Alten. When the King's German Legion ceased to exist, Alten was given the command of the Hanoverians in France, and in 1818 he returned to Hanover, where he became subsequently minister of war and foreign affairs, and rose to be field-marshal, being retained on the British Army list at the same time as Major-General Sir Charles Alten, G. C. B. He died in 1840. A memorial to Alten has been erected at Hanover.

See Glentleman's Magazine, 1840; N. L. Beamish, Hist. of the King's German Legion, 2 vols. (1832-1837).

ALTENA, a town of Germany, in the Prussian province of Westphalia, on the river Lenne, 38 m. S.S.E. from Dortmund. Pop. (1900) 12,769. It consists of a single street, winding up a deep valley for about 3 m. There are three churches, a museum, high grade and popular schools. Its hardware industries are important, and embrace iron rolling, the manufacture of fine wire, needles, springs and silver ornaments. On the neighbouring Schlossberg is the ancestral castle of the counts of La Marok, ancestors, on the female side, of the Prussian royal house.

ALTENBURG, a town of Germany, capital of the duchy of Saxe-Altenburg, situated near the river Pleisse, 23 m. S. of Leipzig, and at the junction of the Saxon state railways Leipzig- Hof and Altenburg-Zeitz. Pop. (1905) 38,811. The town from its hilly position is irregularly built, but many of its streets are wide, and contain a number of large and beautiful buildings. Its ancient castle is picturesquely situated on a lofty porphyry rock, and is memorable as the place from which, in 1455, Kunz von Kaufungen carried off the young princes Albert and Ernest, the founders of the present royal and ducal families of Saxony. Its beautiful picture gallery, containing portraits of several of the famous princes of the house of Wettin, was almost totally destroyed by fire in January 1905. Altenburg is the seat of the higher courts of the Saxon duchies, and possesses a cathedral and several churches, schools, a library, a gallery of pictures and a school of art, an infirmary and various learned societies. There is also a museum, with natural history, archaeological, and art collections, and among other buildings may be mentioned St Bartholomew's church (1089), the town hall (1562-1564), a lunatic asylum, teachers' seminary and an agricultural academy. There is considerable traffic in grain and cattle brought from the surrounding districts; and twice a year there are large horse fairs. Cigars, woollen goods, gloves, hats and porcelain are among the chief manufactures. There are lignite mines in the vicinity.

ALTENSTEIN, a castle upon a rocky mountain in Saxe- Meiningen, on the south-western slope of the Thuringerwald, not far from Eisenach. It is the summer residence of the dukes of Meiningen, and is surrounded by a noble park, which contains, among other objects of interest, a remarkable underground cavern, 500 ft. long, through which flows a large and rapid stream. Boniface, the apostle of the Germans, lived and preached at Altenstein in 724; and near by is the place where, in 1521, Luther was seized, by the order of the elector Frederick the Wise, to be carried off to the Wartburg. An old beech called ``Luther's tree,'' which tradition connected with the reformer, was blown down in 1841, and a small monument now stands in its place.

ALTERNATION (from Lat. aiternare, to do by turns), strictly, the process of ``alternating''' i.e. of two things following one another regularly by turns, as night alternates with day. A somewhat different sense is attached to some usages of the derivatives. Thus, in American political representative bodies and in the case of company directors, a substitute is sometimes called an ``alternate.'' An ``alternative'' IS that which is offered as a choice of two things, the acceptance of the one implying the rejection of the other. It is incorrect to speak of more than two alternatives, though Mr Gladstone wrote in 1857 of a fourth (Oxf. Essays, 26). When there is only one course open there is said to be no alternative.

ALTHAEA, in classical legend, daughter of Thestius, king of Aetolia, wife of Oeneus, king of Calydon, and mother of Meleager (q.v..)

ALTING, JOHANN HEINRICH (1583--1644), German divine, was born at Emden, where his father, Menso Alting ( 1541-1612), was minister. Johann studied with great success at the universities of Groningen and Herborn. In 1608 he was appointed tutor of Frederick, afterwards elector-palatine, at Heidelberg, and in 1612 accompanied him to England. Returning in 1613 to Heidelberg, after the marriage of the elector with Princess Elizabeth of England, he was appointed professor of dogmatics, and in 1616 director of the theological department in the Collegium Sapientiae. In 1618, along with Abraham Scultetus, he represented the university in the synod of Dort. When Count Tilly took the city of Heidelberg (1622) and handed it over to plunder, Alting found great difficulty in escaping the fury of the soldiers. He first retired to Schorndorf; but, offended by the ``semi-Pelagianism'' of the Lutherans with whom he was brought in contact, he removed to Holland, where the unfortunate elector and ``Winter King'' Frederick, in exile after his brief reign in Bohemia, made him tutor to his eldest son. In 1627 Alting was appointed to the chair of theology at Groningen, where he continued to lecture, with increasing reputation, until his death in 1644. Though an orthodox Calvinist, Alting laid little stress on the sterner side of his creed and, when at Dort he opposed the Remonstrants, he did so mainly on the ground that they were ``innovators.'' Among his works are: --Notae in Decadem Problematum Jacobi Behm (Heidelberg, 1618); Scripta Pheologica Meidelbergensia (Amst., 1662); Exegesis Augustanae Confessionis (Amst., 1647).

ALTINUM (mod. Altino), an ancient town of Venetia, 12 m. S.E. of Tarvisium (Treviso), on the edge of the lagoons. It was probably only a small fishing village until it became the point of junction of the Via Postumia and the Via Popillia (see AQUILEIA). At the end of the republic it was a municipium. Augustus and his successors brought it into further importance as a point on the route between Italy and the north-eastern portions of the empire. After the foundation of the naval station at Ravenna, it became the practice to take ship from there to Altinum, instead of following the Via Popillia round the coast, and thence to continue the journey by land. A new road, the Via Claudia Augusta, was constructed by the emperor Claudius from Altinum to the Danube, a distance of 350 m., apparently by way of the Lake of Constance. The place thus became of considerable strategic and commercial importance, and the comparatively mild climate (considering its northerly situation) led to the erection of villas which Martial (Epigr. iv. 25) compares with those of Baiae. It was destroyed by Attila in A.D. 452, and its inhabitants took refuge in the islands of the lagoons, forming settlements from which Venice eventually sprang.

ALTITUDE (Lat. altitudo, from altus, high), height or eminence, and particularly the height above the ground or above sea-level. In geometry, the altitude of a triangle is the length of the perpendicular from the vertex to the base. In astronomy, the altitude of a heavenly body is the apparent angular elevation of the body above the plane of the horizon (see ASTRONOMY: Spherical). Apparent altitude is the value which is directly observed; true altitude is deduced by correcting for astronomical refraction and dip of the horizon; geocentric altitude by correcting for parallax.

ALTMUHL, a river of Germany, in the kingdom of Bavaria. It is an important left bank tributary of the Danube, rising in the Franconian plateau (Frankische Terrasse), and after a tortuous course of 116 m., at times flowing through meadows and again in weird romantic gorges, joins the Danube at Kelheim. From its mouth it is navigable up to Dietfurt (18 m.), whence the Ludwigscanal (100 m. long) proceeds to Bamberg on the Regnitz, thus establishing communication between the Danube and the Rhine.

ALTO (Ital. for ``high',), a musical term applied to the highest adult male voice or counter-tenor, and to the lower boy's or woman's (contralto) Voice.

ALTON, a market-town in the Fareham parliamentary division of Hampshire, England, 46 1/2 m. S.W. of London by the London & South-Western railway. Pop. of urban district (1901) 5479. It has a pleasant undulating site near the headwaters of the river Wey. Of the church of St Lawrence part, including the tower, is Norman; the building was the scene of a fierce conflict between the royalist and parliamentary troops in 1643. There is a museum of natural history; the collection is reminiscent of the famous naturalist Gilbert White, of Selborne in this vicinity. Large markets and fairs are held for corn, hops, cattle and sheep; and the town contains some highly reputed ale breweries, besides paper mills and iron foundries.

ALTON, a city of Madison county, Illinois, U.S.A., in the W. part of the state, on the Mississippi river, about 10 m. above the mouth of the Missouri, and about 25 m. N. of St Louis, Missouri. Pop. (1890) 10,294; (1900) 14,210, of whom 1638 were foreign-born; (1910) 17,528. Alton is served by the Chicago & Alton, the Chicago, Peoria & St Louis, the Cleveland, Cincinnati, Chicago & St Louis, and the Illinois Terminal railways. The river is here spanned by a bridge. The residential portion of the city lies on the river bluffs, some of which rise to a height of 250 ft. above the water level, and the business streets are on the bottom lands of the river. Alton has a public library and a public park. Upper Alton (pop. 2918 in 1910), about 1 1/2 m. N.E. of Alton, is the seat of the Western Military Academy (founded in 1879 as Wyman Institute; chartered in 1892), and of Shurtleff College (Baptist, founded in 1827 at Rock Spring, removed to Upper Alton in 1831, and chartered in 1833), which has a college of liberal arts, a divinity school, an academy and a school of music; and the village of Godfrey, 5 1/2 m. N. of Alton, is the seat of the Monticello Ladies' Seminary, founded by Benjamin Godfrey, opened in 1838, and chartered in 1841. Among the manufactures of Alton are iron and glass ware, miners' tools, shovels, coal-mine cars, flour, and agricultural implements; and there are a large oil refinery and a large lead smelter. The value of the city's factory products increased from $4,250,389 in 1900 to $8,696,814 in 1905, or 104.6%.

The first settlement on the site of Alton was made in 1807, when a trading post was established by the French. The town was laid out in 1817, was first incorporated in 1821, and in 1827 was made the seat of a state penitentiary, which was later removed to Joliet, the last prisoners being transferred in 1860. Alton was first chartered as a city in 1837. In 1836 the Rev. Elijah P. Lovejoy (1802-1837), a native of Albion, Maine, removed the Observer, a religious (Presbyterian) periodical of which he was the editor, from St Louis to Alton. He had attracted considerable attention in St Louis by his criticisms of slavery, but though he believed in emancipation, he was not a radical abolitionist. After coming to Alton his anti-slavery views soon became more radical, and in a few months he was an avowed abolitionist. His views were shared by his brother, Owen Lovejoy (1811-1864), a Congregational minister, who also at that time lived in Alton, and who from 1857 until his death was an able anti-slavery member of Congress. Most of the people of southern Illinois were in sympathy with slavery, and consequently the Lovejoys became very unpopular. The press of the Observer was three time destroyed, and on the 7th of November 1837 E. P. Loveioy was killed while attempting to defend against a mob a fourth press which he had recently obtained and which was stored in a warehouse in Alton. His death caused intense excitement throughout the country, and he was everywhere regarded by abolitionists as a martyr to their cause. In 1897 a monument, a granite column surmounted by a bronze statue of Victory, was erected in his honour by the citizens of Alton and by the state.

See Henry Tanner, The Martyrdom of Lovejoy (Chicago, 1881), and ``The Alton Tragedy'' in S. J. May's Some Recollections of Our Anti-Slavery Conflict (Boston, 1869).

ALTONA, a town of Germany, in the Prussian province of Schleswig-Holstein, on the right bank of the Elbe immediately west of Hamburg. Though administratively distinct, the two cities so closely adjoin as virtually to form one whole. Lying higher than Hamburg, Altona enjoys a purer and healthier atmosphere. It has spacious squares and streets, among the latter the Palmaille, a stately avenue ending on a terrace about 100 ft. above the Elbe, whence a fine view is obtained of the river and the lowlands beyond. Of the six Evangelical churches, the Hauptkirche (parish church), with a lofty steeple, is noteworthy. The main thoroughfares are embellished by several striking monuments, notably the memorials of the wars of 1864 and 1870, bronze statues of the emperor William I. and Bismarck and the column of Victory (Siegessaule). The museum (1901) is an imposing building in the German Renaissance style and contains, in addition to a valuable library, ethnographical and natural history collections. Its site is that formerly occupied by the terminus of the Schleswig-Holstein railways, but a handsome central station lying somewhat farther to the N., connected with Hamburg by an elevated railway, now accommodates all the traffic and provides through communication with the main Prussian railway systems. There are also fine municipal and judicial buildings, a theatre (under the same management as the Stadttheater in Hamburg), a gymnasium, technical schools, a school of navigation and a hospital. In respect of its local industries Altona has manufactures of tobacco and cigars, of machinery, woollens, cottons and chemicals. There are also extensive breweries, tanneries and soap and oil works. Altona carries on an extensive maritime trade with Great Britain, France and America, but it has by no means succeeded in depriving Hamburg of its commercial superiority -- indeed, so dependent is it upon its rival that most of its business is transacted on the Hamburg exchange, while the magnificent warehouses on the Altona river bank are to a large extent occupied by the goods of Hamburg merchants. Since 1888, when Altona joined the imperial Zollverein, approximately half a million sterling has been spent upon harbour improvement works. The exports and imports resemble those of Hamburg. In the ten years 1871-1880, the port was entered on an average annually by 737 vessels of 67,735 tons, in 1881-1890 by 608 vessels of 154,713 tons, and in 1891-1898 by 839 vessels of 253,384 tons.

In 1890 the populous suburbs of Ottensen to the W., where the poet Gottlieb Klopstock lies buried, Bahrenfeld, Othmarschen and Ovelgonne were incorporated. Without these suburbs the growth of the town may be seen from the following figures: -- (1864, when it ceased to he Danish) 53,039; (1880) 91,049; (1885) 104,717; (1890) together with the four suburbs, 143,249; (1895) 148,944; (1900) 161,508; (1905) 168,301. Altona is the headquarters of the IX. German army corps.

The name Altona is said to be derived from allzu-nah (``all too near''), the Hamburgers' designation for an inn which in the middle of the 16th century lay too close to their territory. For a long time this was the only house in the locality. When in 1640 Altona passed to Denmark it was a small fishing village. Its rise to its present position is mainly due to the fostering care of the Danish kings who conferred certain customs privileges and exemptions upon it with a view to making it a formidable rival to Hamburg. In 1713 it was burnt by the Swedes, but rapidly recovered from this disaster, and despite the trials of the Napoleonic wars, gradually increased in prosperity. In 1853, owing to the withdrawal by Denmark of its customs privileges, its trade waned. In 1864 Altona was occupied in the name of the German Confederation, passed to Prussia after the war of 1866, and 1888 together with Hamburg joined the Zollverein, while retaining certain free trade rights over the Freihafengebiet which it shares with Hamburg and Wandsbek.

See Wichmann, Geschichte Altonas (2 vols., Alt., 1896); Ehrenberg & Stahl, Altonas topographische Entwickelung (Alt., 1894).

ALTOONA, a city of Blair county, Pennsylvania, U.S.A., about 117 m. E. by N. of Pittsburg. Pop. (1890) 30,337; (1900) 38,973, of whom 3301 were foreign-born, 1518 being German; (1010) 52,127. It lies in the upper end of Logan Valley at the base or the Alleghany mountains, about 1180 ft. above sea-level, and Commands views of some of the most picturesque mountain scenery in the state. A short distance to the W. is the famous Horseshoe Bend of the Pennsylvania

railway. Altoona is served by the Pennsylvania railway, and is one of the leading railway cities in the United States. Its freight yard is 7 m. long, and has 221 m. of tracks. Large numbers of eastbound coal trains from the mountains and westbound ``empties'' returning to the mines stop here; and the cars of these trains are classified here and new trains made up. Locomotives and cars are sent to Altoona to be repaired from all over the Pennsylvania railway system E. of Pittsburg, and cars and locomotives are built here; and in the south Altoona foundries car wheels and general castings for locomotives and cars are made. The several departments of railway work are used to give training in a sort of railway university. Graduates of technical schools are received as special apprentices and are directed in a course of four years through the erecting shops, vice shop, blacksmith shop, boiler shop, roundhouse, test department, machine shop, air-brake shop, iron foundry, car shop, work of firing on the road, office work in the motive power accounting department, and drawing room; the most competent may be admitted through the grades of inspector, in the office of the master mechanic or of the road foreman of engines, assistant master mechanic, assistant engineer of motive power, master mechanic and superintendent of motive power. The Pennsylvania railway, co-operating with the public school authorities, established at Altoona, in 1907, a railway high school, the first institution of the kind in the country. It has a well-equipped drawing room, carpenter shop, forging room, foundry, science laboratories and machinery department, in which expert instruction is given. In 1905 the city's factory products were valued at $14,349,963, and in this year the railway shops gave employment to 83.7% of all wage-earners employed in manufacturing establishments. The manufacture of silk is the only other important industry in the city. The site of the city (formerly farming land) was purchased in 1849 by the Pennsylvania Railroad Company and was laid out as a town. It was incorporated as a borough in 1854 and was chartered as a city in 1868.

ALTO-RELIEVO (Ital. for ``high relief''), the term applied to sculpture that projects from the plane to which it is attached to the extent of more than one-half the outline of the principal figures, which may be nearly or in parts entirely detached from the background. It is thus distinguished from basso-relievo (q.v.), in which there is a greater or less approximation in effect to the pictorial method, the figures being made to appear as projecting more than half their outline without actually doing so. At the same time it is not only the actual degree of relief which is implied by these two terms, but a resultant difference also of design and treatment necessitated by the contingent differences of light and shadow. (See RELIEF and SCULPTURE.)

ALTOTTING, a town of Germany, in the kingdom of Bavaria, On the Morren, not far from its junction with the Inn, and on the Mulildorf-Burghausen railway. Pop. (1900) 4344. It has long been a place of pilgrimage to which Roman Catholics, especially from Austria, Bavaria and Swabia resort in large numbers, on account of a celebrated image of the Virgin Mary in the Holy Chapel, which also contains the hearts of some Bavarian princes in silver caskets. In the church of St Peter and St Paul is the tomb of Tilly.

ALTRANSTADT, a village of Germany, in Prussian Saxony near Merseburg (q.v.), with (1900) 813 inhabitants. Altranstadt is famous in history for two treaties concluded here: (1) the peace which Augustus II., king of Poland and elector of Saxony, was forced to ratify, on the 24th of September 1706, with Charles XII. of Sweden, whereby the former renounced the throne of Poland in favour of Stanislaus Leszczynski -- a treaty which Augustus declared null and void after Charles XII.'s defeat at Poltava (8th of July 1709); (2) the treaty of the 31st of August 1707, by which the emperor Joseph I. guaranteed to Charles XII. religious tolerance and liberty of conscience for the Silesian protestants.

ALTRINCHAM, or ALTRINOHAM (and so pronounced), a market-town, in the Altrincham padiamentary division of Cheshire England, 8 m. S.W. by S. of Manchester, on the London & North-Western, Manchester, South Junction & Altrincham and Cheshire Lines railways. Pop. of urban district (1901) 16,831. Many residences in the locality are occupied by those whose business lies in Manchester, who are attracted by the healthy climate and the vicinity of Bowdon Downs and Dunham Massey Woods. Market gardening is carried on, large quantities of fruit and flowers being grown for sale in Manchester. Cabinet-making is also practised; and there are sawmills, iron foundries, and manufactures of cotton, yarn and worsted.

Altrincham (Aldringham) was originally included in the barony of Dunham Massey, one of the eight baronies founded by Hugh, earl of Chester, after the Conquest. An undated charter from Hamo de Massey, lord of the barony, in the reign of Edward I., constituted Altrincham a free borough, with a gild merchant, the customs of Macclesfield, the right to elect reeves and bailiffs for the common council and other privileges. In 1290 the same Hamo obtained a grant of a Tuesday market and a three days' fair at the feast of the Assumption of the Virgin; but in 1319, by a charter from Edward II., the date of the fair was changed to the feast of St James the Apostle. A mayor of Altrincham is mentioned by name in 1452, but the office probably existed long before this date; it has now for centuries been a purely nominal appointment, the chief duty consisting in the opening of the annual fairs. The trade in worsted and woollen yarns, which formerly furnished employment to a large section of the population, has now completely declined, partly owing to the introduction of Irish worsted.

See Victoria County History, Cheshire; Alfred Ingham, History of Altrincham and Bowdon (Altrincham, 1879).

ALTRUISM (Fr. autrui, from Lat. alter, the other of two), a philosophical term used in ethics for that theory of conduct which regards the good of others as the end of moral action. It was invented by Auguste Comte and adopted by the English positivists as a convenient antithesis to egoism. According to Comte the only practical method of social regeneration is gradually to inculcate the true social feeling which subordinates itself to the welfare of others. The application to sociological problems of the physical theory of organic evolution further developed the altruistic theory. According to Herbert Spencer, the life of the individual in the perfect society is identical with that of the state: in other words, the first object of him who would live well must be to take his part in promoting the well-being of his fellows individually and collectively. Pure egoism and pure altruism are alike impracticable. For on the one hand unless the egoist's happiness is compatible to some extent with that of his fellows, their opposition will almost inevitably vitiate his perfect enjoyment; on the other hand, the altruist whose primary object is the good of others, must derive his own highest happiness -- i.e. must realize himself most completely -- in the fulfilment of this object. In fact, the altruistic idea, in itself and apart from a further definition of the good, is rather a method than an end.

The self-love theory of Hobbes, with its subtle perversions of the motives of ordinary humanity, led to a reaction which culminated in the utilitarianism of Bentham and the two Mills; but their theory, though superior to the extravagant egoism of Hobbes, had this main defect, according to Herbert Spencer, that it conceived the world as an aggregate of units, and was so far individualistic. Sir Leslie Stephen in his Science of Ethics insisted that the unit is the social organism, and therefore that the aim of moralists is not the ``greatest happiness of the greatest number,'' but rather the ``health of the organism.'' The socialistic tendencies of subsequent thinkers have emphasized the ethical importance of altruistic action, but it must be remembered always that it is ultimately only a form of action, that it may be commended in all types of ethical theory, and that it is a practical guide only when it is applied in accordance with a definite theory of ``the good.'' Finally, he who devotes himself on principle to furthering the good of others as his highest moral obligation is from the highest point of view realizing, not sacrificing, himself.

See works of Comte, Spencer, Stephen, and text-books of ethics (cf. bibliography at end of article ETHICS).

ALTWASSER, a town of Germany, in the Prussian province of Silesia, 43 m. by rail S.W. from Breslau, and 3 m. N. from Waldenburg. It has factories for glass, porcelain, machinery, cotton-spinning, iron-foundries and coal-mines. Pop. (1900) 12,144.

ALTYN-TAGH, or ASTYN-TAOH, one of the chief constituent ranges of the Kuen-lun (q.v.) in Central Asia, separating Tibet from east Turkestan and the Desert of Gobi.

ALUM, in chemistry, a term given to the crystallized double sulphates of the typical formula M2SO4.M2111.(SO4)324H2O, Where M is the sign of an alkali metal (potassium, sodium, rubidium, caesium), silver or ammonium, and M111 denotes one of the trivalent metals, aluminium, chromium or ferric iron. These salts are employed in dyeing and various other industrial processes. They are soluble in water, have an astringent, acid, and sweetish taste, react acid to litmus, and crystallize in regular octahedra. When heated they liquefy; and if the heating be continued, the water of crystallization is driven off, the salt froths and swells, and at last an amorphous powder remains.

Potash alum is the common alum of commerce, although both soda alum and ammonium alum are manufactured. The presence of sulphuric acid in potash alum was known to the alchemists. J. H. Pott and A. S. Marggraf demonstrated that alumina was another constituent. Pott in his Lithogeognosia showed that the precipitate obtained when an alkali is poured into a solution of alum is quite different from lime and chalk, with which it had been confounded by G. E. Stahl. Marggraf showed that alumina is one of the constituents of alum, but that this earth possesses peculiar properties, and is one of the ingredients in common clay (Experiences faites sur la terre de l'alun, Marggraf's Opusc. ii. 111) . He also showed that crystals of alum cannot be obtained by dissolving alumina in sulphuric acid and evaporating the solutions, but when a solution of potash or ammonia is dropped into this liquid, it immediately deposits perfect crystals of alum (Sur la regeneration de l'alun, Marggraf's Opusc. ii. 86).

T. O. Bergman also observed that the addition of potash or ammonia made the solution of alumina in sulphuric acid crystallize, but that the same effect was not produced by the addition of soda or of lime (De confectione aluminus, Bergman's Opusc. i. 225), and that potassium sulphate is frequently found in alum.

After M. H. Klaproth had discovered the presence of potassium in leucite and lepidolite, it occurred to L. N. Vauquelin that it was probably an ingredient likewise in many other minerals. Knowing that alum cannot be obtained in crystals without the addition of potash, he began to suspect that this alkali constituted an essential ingredient in the salt, and in 1797 he published a dissertation demonstrating that alum is a double salt, composed of sulphuric acid, alumina and potash (Annales de chimie, xxii. 258). Soon after, J. A. Chaptal published the analysis of four different kinds of alum, namely, Roman alum, Levant alum, British alum and alum manufactured by himself. This analysis led to the same result as that of Vauquelin (Ann. de chim xxii. 280).

The word alumen, which we translate alum, occurs in Pliny's Natural History. In the 15th chapter of his 35th book he gives a detailed description of it. By comparing this with the account of stupteria given by Dioscorides in the 123rd chapter of his 5th book, it is obvious that the two are identical. Pliny informs us that alumen was found naturally in the earth. He calls it salsugoterrae. Different substances were distinguished by the name of ''alumen''; but they were all characterized by a certain degree of astringency, and were all employed in dyeing and medicine, the light-coloured alumen being useful in brilliant dyes, the dark-coloured only in dyeing black or very dark colours. One species was a liquid, which was apt to be adulterated; but when pure it had the property of blackening when added to pomegranate juice. This property seems to characterize a solution of iron sulphate in water; a solution of ordinary (potash) alum would possess no such property. Pliny says that there is another kind of alum which the Greeks call schistos. It forms in white threads upon the surface of certain stones. From the name schistos, and the mode of formation, there can be little doubt that this species was the salt which forms spontaneously on certain slaty minerals, as alum slate and bituminous shale, and which consists chiefly of sulphates of iron and aluminium. Possibly in certain places the iron sulphate may have been nearly wanting, and then the salt would be white, and would answer, as Pliny says it did, for dyeing bright colours. Several other species of alumen are described by Pliny, but we are unable to make out to what minerals he alludes.

The alumen of the ancients, then, was not the same with the alum of the moderns. It was most commonly an iron sulphate, sometimes probably an aluminium sulphate, and usually a mixture of the two. But the ancients were unacquainted with our alum. They were acquainted with a crystallized iron sulphate, and distinguished it by the names of misy, sory, chalcanthum (Pliny xxxiv. 12). As alum and green vitriol were applied to a variety of substances in common, and as both are distinguished by a sweetish and astringent taste, writers, even after the discovery of alum, do not seem to have discriminated the two salts accurately from each other. In the writings of the alchemists we find the words misy, sory, chalcanthum applied to alum as well as to iron sulphate; and the name atramentum sutorium, which ought to belong, one would suppose, exclusively to green vitriol, applied indifferently to both. Various minerals are employed in the manufacture of alum, the most important being alunite (q.v.) or alum-stone, alum schist, bauxite and cryolite.

In order to obtain alum from alunite, it is calcined and then exposed to the action of air for a considerable time. During this exposure it is kept continually moistened with water, so that it ultimately falls to a very fine powder. This powder is then lixiviated with hot water, the liquor decanted, and the alum allowed to crystallize. The alum schists employed in the manufacture of alum are mixtures of iron pyrites, aluminium silicate and various bituminous substances, and are found in upper Bavaria, Bohemia, Belgium and Scotland. These are either roasted or exposed to the weathering action of the air. In the roasting process, sulphuric acid is formed and acts on the clay to form aluminium sulphate, a similar condition of affairs being produced during weathering. The mass is now systematically extracted with water, and a solution of aluminium sulphate of specific gravity 1.16 is prepared. This solution is allowed to stand for some time (in order that any calcium sulphate and basic ferric sulphate may separate), and is then evaporated until ferrous sulphate crystallizes on cooling; it is then drawn off and evaporated until it attains a specific gravity of 1.40. It is now allowed to stand for some time, decanted from any sediment, and finally mixed with the calculated quantity of potassium sulphate (or if ammonium alum is required, with ammonium sulphate), well agitated, and the alum is thrown down as a finely-divided precipitate of alum meal. If much iron should be present in the shale then it is preferable to use potassium chloride in place of potassium sulphate.

In the preparation of alum from clays or from bauxite, the material is gently calcined, then mixed with sulphuric acid and heated gradually to boiling; it is allowed to stand for some time, the clear solution drawn off and mixed with acid potassium sulphate and allowed to crystallize. When cryolite is used for the preparation of alum, it is mixed with calcium carbonate and heated. By this means, sodium aluminate is formed; it is then extracted with water and precipitated either by sodium bicarbonate or by passing a current of carbon dioxide through the solution. The precipitate is then dissolved in sulphuric acid, the requisite amount of potassium sulphate added and the solution allowed to crystallize.

Potash alum, K2SO4.Al2(SO4)3.24H2O, crystallizes in regular

octahedra and is very soluble in water. The solution redens litmus and is an astringent. When heated to nearly a red heat it gives a porous friable mass which is known as ``burnt alum.'' It fuses at 92 deg. C. in its own water of crystallization. ``Neutral alum'' is obtained by the addition of as much sodium carbonate to a solution of alum as will begin to cause the separation of alumina; it is much used in mordanting. Alum finds application as a mordant, in the preparation of lakes for sizing hand-made paper and in the clarifying of turbid liquids.

Sodium alum, Na2SO4.Al2(SO4)3.24H2O, occurs in nature as the mineral mendozite. It is very soluble in water, and is extremely difficult to purify. In the preparation of this salt, it is preferable to mix the component solutions in the cold, and to evaporate them at a temperature not exceeding 60 deg. C. 100 parts of water dissolve 110 parts of sodium alum at 0 deg. C. (W. A. Tilden, Jour. Chem. Soc., 1884, 45, p. 409), and 51 parts at 16 deg. C. (E. Auge, Comptes rendus, 1890, 110, p. 1139).

Chrome alum, K2SO4.Cr2(SO 4/0)3.24H2O, appears chiefly as a by-product in the manufacture of alizarin, and as a product of the reaction in bichromate batteries.

The solubility of the various alums in water varies greatly, sodium alum being readily soluble in water, whilst caesium and rubidium alums are only sparingly soluble. The various solubilities are shown in the following table: --

Ammonium Alum. Caesium Alum. Potash Alum. Rubidium Alum. t deg. C. 100 parts t deg. C. 100 parts t deg. C. 100 parts t deg. C. 100 parts water water water water dissolve dissolve dissolve dissolve 0 2.62 0 0.19 0 3.9 0 0.71 10 4.5 10 0.29 10 9.52 10 1.09 50 15.9 50 1.235 50 44.11 50 4.98 80 35.2 80 5.29 80 134.47 80 21.60 100 70.83 100 357.48 Poggiale C. Setterberg Poggiale C. Setterberg Ann. Chim. phys. Ann. 1882, [3] 8, p. 467 211, p. 104

ALUMINIUM (symbol Al; atomic weight 27.0), a metallic chemical element. Although never met with in the free state, aluminium is very widely distributed in combination, principally as silicates. The word is derived from the Lat. alumen (see ALUM), and is probably akin to the Gr. als (the root of salt, halogen, &c.). In 1722 F. Hoffmann announced the base of alum to be an individual substance; L. B. Guyton de Morveau suggested that this base should be called alumine, after Sel alumineux, the French name for alum; and about 1820 the word was changed into alumina. In 1760 the French chemist, T. Baron de Henouville, unsuccessfully attempted ``to reduce the base of alum'' to a metal, and shortly afterwards various other investigators essayed the problem in vain. In 1808 Sir Humphry Davy, fresh from the electrolytic isolation of potassium and sodium, attempted to decompose alumina by heating it with potash in a platinum crucible and submitting the mixture to a current of electricity; in 1809, with a more powerful battery, he raised iron wire to a red heat in contact with alumina, and obtained distinct evidence of the production of an iron-aluminium alloy. Naming the new metal in anticipation of its actual birth, he called it alumium; but for the sake of analogy he was soon persuaded to change the word to aluminum, in which form, alternately with aluminium, it occurs in chemical literature for some thirty years.

Preparation.

In the year 1824, endeavouring to prepare itbychemicalmeans, H. C. Oersted heated its chloride with potassium amalgam, and failed in his object simply by reason of the mercury, so that when F. Wohler repeated the experiment at Gottingen in 1827, employing potassium alone as the reducing agent, he obtained it in the metallic state for the first time. Contaminated as it was with potassium and with platinum from the crucible, the metal formed a grey powder and was far from pure; but in 1845 he improved his process and succeeded in producing metallic globules wherewith he examined its chief properties, and prepared several compounds hitherto unknown. Early in 1854, H. St Claire Deville, accidentally and in ignorance of Wohler's later results, imitated the 1845 experiment. At once observing the reduction of the chloride, he realized the importance of his discovery and immediately began to study the commercial production of the metal. His attention was at first divided between two processes -- the chemical method of reducing the chloride with potassium, and an electrolytic method of decomposing it with a carbon anode and a platinum cathode, which was simultaneously imagined by himself and R. Bunsen. Both schemes appeared practically impossible; potassium cost about L. 17 per lb, gave a very small yield and was dangerous to manipulate, while on the other hand, the only source of electric current then available was the primary battery, and zinc as a store of industrial energy was utterly out of the question. Deville accordingly returned to pure chemistry and invented a practicable method of preparing sodium which, having a lower atomic weight than potassium, reduced a larger proportion. He next devised a plan for manufacturing pure alumina from the natural ores, and finally elaborated a process and plant which held the field for almost thirty years. Only the discovery of dynamo-electric machines and their application to metallurgical processes rendered it possible for E. H. and A. H. Cowles to remove the industry from the hands of chemists, till the time when P. T. L. Heroult and C. M. Hall, by devising the electrolytic method now in use, inaugurated the present era of industrial electrolysis.

Ores.

The chief natural compounds of aluminium are four in number: oxide, hydroxide (hydrated oxide), silicate and fluoride. Corundum, the only important native oxide (Al2O3), occurs in large deposits in southern India and the United States. Although it contains a higher percentage of metal (52.9%) than any other natural compound, it is not at present employed as an ore, not only because it is so hard as to be crushed with difficulty, but also because its very hardness makes it valuable as an abrasive. Cryolite (AlF3.5NaF) is a double fluoride of aluminium and sodium, which is scarcely known except on the west coast of Greenland. Formerly it was used for the preparation of the metal, but the inaccessibility of its source, and the fact that it is not sufficiently pure to be employed without some preliminary treatment, caused it to be abandoned in favour of other salts. When required in the Heroult-Hall process as a solvent, it is sometimes made artificially. Aluminium silicate is the chemical body of which all clays are nominally composed. Haolin or China clay is essentially a pure disilicate (Al2O3.2SiO2.2H2O), occurring in large beds almost throughout the world, and containing in its anhydrous state 24.4% of the metal, which, however, in common clays is more or less replaced by calcium, magnesium, and the alkalis, the proportion of silica sometimes reaching 70%. Kaolin thus seems to be the best ore, and it would undoubtedly be used were it not for the fatal objection that no satisfactory process has yet been discovered for preparing pure alumina from any mineral silicate. If, according to the present method of winning the metal, a bath containing silica as well as alumina is submitted to electrolysis, both oxides are dissociated, and as silicon is a very undesirable impurity, an alumina contaminated with silica is not suited for reduction. Bauxite is a hydrated oxide of aluminium of the ideal composition, Al2O3.2H2O. It is a somewhat widely distributed mineral, being met within Styria, Austria, Hesse, French Guiana, India and Italy; but the most important beds are in the south of France, the north of Ireland, and in Alabama, Georgia and Arkansas in North America. The chief Irish deposits are in the neighbourhood of Glenravel, Co. Antrim, and have the advantage of being near the coast, so that the alumina can be transported by water-carriage. After being dried at 100 deg. C., Antrim bauxite contains from 33 to 60% of alumina, from 2 to 30% of ferric oxide, and from 7 to 24% of silica, the balance being titanic acid and water of combination. The American bauxites contain from 38 to 67% of alumina, from 1 to 23% of ferric oxide, and from 1 to 32% of silica. The French bauxites are of fairly constant composition, containing usually from 58 to 70% of alumina, 3 to 15% of foreign matter, and 27% made

up of silica, iron oxide and water in proportions that vary with the colour and the situation of the beds.

Before the application of electricity, only two compounds were found suitable for reduction to the metallic state. Alumina itself is so refractory that it cannot be melted save by the oxyhydrogen blowpipe or the electric arc, and except in the molten state it is not susceptible of decomposition by any chemical reagent. Deville first selected the chloride as his raw material, but observing it to be volatile and extremely deliquescent, he soon substituted in its place a double chloride of aluminium and sodium. Early in 1855 John Percy suggested that cryolite should be more convenient, as it was a natural mineral and might not require purification, and at the end of March in that year, Faraday exhibited before the Royal Institution samples of the metal reduced from its fluoride by Dick and Smith. H. Rose also carried out experiments on the decomposition of cryolite, and expressed an opinion that it was the best of all compounds for reduction; but, finding the yield of metal to be low, receiving a report of the difficulties experienced in mining the ore, and fearing to cripple his new industry by basing it upon the employment of a mineral of such uncertain supply, Deville decided to keep to his chlorides. With the advent of the dynamo, the position of affairs was wholly changed. The first successful idea of using electricity depended on the enormous heating powers of the arc. The infusibility of alumina was no longer prohibitive, for the molten oxide is easily reduced by carbon. Nevertheless, it was found impracticable to smelt alumina electrically except in presence of copper, so that the Cowles furnace yielded, not the pure metal, but an alloy. So long as the metal was principally regarded as a necessary ingredient of aluminium-bronze, the Cowles process was popular, but when the advantages of aluminium itself became more apparent, there arose a fresh demand for some chief method of obtaining it unalloyed. It was soon discovered that the faculty of inducing dissociation possessed by the current might now be utilized with some hope of pecuniary success, but as electrolytic currents are of lower voltage than those required in electric furnaces, molten alumina again became impossible. Many metals, of which copper, silver and nickel are types, can be readily won or purified by the electrolysis of aqueous solutions, and theoretically it may be feasible to treat aluminium in an identical manner. In practice, however, it cannot be thrown down electrolytically with a dissimilar anode so as to win the metal, and certain difficulties are still met with in the analogous operation of plating by means of a similar anode. Of the simple compounds, only the fluoride is amenable to electrolysis in the fused state, since the chloride begins to volatilize below its melting-point, and the latter is only 5 deg. below its boiling-point. Cryolite is not a safe body to electrolyse, because the minimum voltage needed to break up the aluminium fluoride is 4.0, whereas the sodium fluoride requires only 4.7 volts; if, therefore, the current rises in tension, the alkali is reduced, and the final product consists of an alloy with sodium. The corresponding double chloride is a far better material; first, because it melts at about 180 deg. C., and does not volatilize below a red heat, and second, because the voltage of aluminium chloride is 2.3 and that of sodium chloride 4.3, so that there is a much wider margin of safety to cover irregularities in the electric pressure. It has been found, however, that molten cryolite and the analogous double fluoride represented by the formula Al2F6.2NaF are very efficient solvents of alumina, and that these solutions can be easily electrolysed at about 800 deg. C. by means of a current that completely decomposes the oxide but leaves the haloid salts unaffected. Molten cryolite dissolves roughly 30% of its weight of pure alumina, so that when ready for treatment the solution contains about the same proportion of what may be termed ``available'' aluminium as does the fused double chloride of aluminium and sodium. The advantages lie with the oxide because of its easier preparation. Alumina dissolves readily enough in aqueous hydrochloric acid to yield a solution of the chloride, but neither this solution, nor that containing sodium chloride, can be evaporated to dryness without decomposition. To obtain the anhydrous single or double chloride, alumina must be ignited with carbon in a current of chlorine, and to exclude iron from the finished metal, either the alumina must be pure or the chloride be submitted to purification. This preparation of a chlorine compound suited for electrolysis becomes more costly and more troublesome than that of the oxide, and in addition four times as much raw material must be handled.

At different times propositions have been made to win the metal from its sulphide. This compound possesses a heat of formation so much lower that electrically it needs but a voltage of 0.9 to decompose it, and it is easily soluble in the fused sulphides of the alkali metals. It can also be reduced metallurgically by the action of molten iron. Various considerations, however, tend to show that there cannot be so much advantage in employing it as would appear at first sight. As it is easier to reduce than any other compound, so it is more difficult to produce. Therefore while less energy is absorbed in its final reduction, more is needed in its initial preparation, and it is questionable whether the economy possible in the second stage would not be neutralized by the greater cost of the first stage in the whole operation of winning the metal from bauxite with the sulphide as the intermediary.

Chemical reductions.

The Deville process as gradually elaborated between 1855 and 1859 exhibited three distinct phases: -- Production of metallic sodium, formation of the pure double chloride of sodium and aluminium, and preparation of the metal by the interaction of the two former substances. To produce the alkali metal, a calcined mixture of sodium carbonate, coal and chalk was strongly ignited in flat retorts made of boiler-plate; the sodium distilled over into condensers and was preserved under heavy petroleum. In order to prepare pure alumina, bauxite and sodium carbonate were heated in a furnace until the reaction was complete; the product was then extracted with water to dissolve the sodium aluminate, the solution treated with carbon dioxide, and the precipitate removed and dried. This purified oxide, mixed with sodium chloride and coal tar, was carbonized at a red heat, and ignited in a current of dry chlorine as long as vapours of the double chloride were given off, these being condensed in suitable chambers. For the production of the final aluminium, 100 parts of the chloride and 45 parts of cryolite to serve as a flux were powdered together and mixed with 35 parts of sodium cut into small pieces. The whole was thrown in several portions on to the hearth of a furnace previously heated to low redness and was stirred at intervals for three hours. At length when the furnace was tapped a white slag was drawn off from the top, and the liquid metal beneath was received into a ladle and poured into cast-iron moulds. The process was worked out by Deville in his laboratory at the Ecole Normale in Paris. Early in 1855 he conducted large-scale experiments at Javel in a factory lent him for the purpose, where he produced sufficient to show at the French Exhibition of 1855. In the spring of 1856 a complete plant was erected at La Glaciere, a suburb of Paris, but becoming a nuisance to the neighbours, it was removed to Nanterre in the following year. Later it was again transferred to Salindres, where the manufacture was continued by Messrs. Pechiney till the advent of the present electrolytic process rendered it no longer profitable.

When Deville quitted the Javel works, two brothers C. and A. Tissier, formerly his assistants, who had devised an improved sodium furnace and had acquired a thorough knowledge of their leader's experiments, also left, and erected a factory at Amfreville, near Rouen, to work the cryolite process. It consisted simply in reducing cryolite with metallic sodium exactly as in Deville's chloride method, and it was claimed to possess various mythical advantages over its rival. Two grave disadvantages were soon obvious -- the limited supply of ore, and, what was even more serious, the large proportion of silicon in the reduced metal. The Amfreville works existed some eight or ten years, but achieved no permanent prosperity. In 1858 or 1859 a small factory, the first in England, was built by F. W. Gerhard at Battersea, who also employed cryolite, made his own sodium, and was able to sell the product at 3s. 9d. per oz. This enterprise

only lasted about four years. Between 1860 and 1874 Messrs Bell Brothers manufactured the metal at Washington, near Newcastle, under Deville's supervision, producing nearly 2 cwt. per year. They took part in the International Exhibition of 1862, quoting a price of 40s. per lb troy.

In 1881 J. Webster patented an improved process for making alumina, and the following year he organized the Aluminium Crown Metal Co. of Hollywood to exploit it in conjunction with Deville's method of reduction. Potash-alum and pitch were calcined together, and the mass was treated with hydrochloric acid; charcoal and water to form a paste were next added, and the whole was dried and ignited in a current of air and steam. The residue, consisting of alumina and potassium sulphate, was leached with water to separate the insoluble matter which was dried as usual. All the by-products, potassium sulphate, sulphur and aluminate of iron, were capable of recovery, and were claimed to reduce the cost of the oxide materially. From this alumina the double chloride was prepared in essentially the same manner as practised at Salindres, but sundry economies accrued in the process, owing to the larger scale of working and to the adoption of W. Weldon's method of regenerating the spent chlorine liquors. In 1886 H. Y. Castner's sodium patents appeared, and The Aluminium Co. of Oldbury was promoted to combine the advantages of Webster's alumina and Castner's sodium. Castner had long been interested in aluminium, and was desirous of lowering its price. Seeing that sodium was the only possible reducing agent, he set himself to cheapen its cost, and deliberately rejecting sodium carbonate for the more expensive sodium hydroxide (caustic soda), and replacing carbon by a mixture of iron and carbon -- the so-called carbide of iron -- he invented the highly scientific method of winning the alkali metal which has remained in existence almost to the present day. In 1872 sodium prepared by Deville's process cost about 4s. per lb, the greater part of the expense being due to the constant failure of the retorts; in 1887 Castner's sodium cost less than 1s. per lb, for his cast-iron pots survived 125 distillations.

In the same year L. Grabau patented a method of reducing the simple fluoride of aluminium with sodium, and his process was operated at Trotha in Germany. It was distinguished by the unusual purity of the metal obtained, some of his samples containing 99.5 to 99.8%. In 1888 the Alliance Aluminium Co., organized to work certain patents for winning the metal from cryolite by means of sodium, erected plant in London, Hebburn and Wallsend, and by 1889 were selling the metal at 11s. to 15s. per lb. The Aluminium Company's price in 1888 was 20s. per lb and the output about 250 lb per day. In 1889 the price was 16s., but by 1891 the electricians commenced to offer metal at 4s. per lb, and aluminium reduced with sodium became a thing of the past.

Electric reduction.

About 1879 dynamos began to be introduced into metallurgical practice, and from that date onwards numerous schemes for utilizing this cleaner source of energy were brought before the public. The first electrical method worthy of notice is that patented by E. H. and A. H. Cowles in 1885, which was worked both at Lockport, New York, U.S.A., and at Milton, Staffordshire. The furnace consisted of a flat, rectangular, firebrick box, packed with a layer of finely-powdered charcoal 2 in. thick. Through stuffing-boxes at the ends passed the two electrodes, made after the fashion of arc-light carbons, and capable of being approached together according to the requirements of the operation. The central space of the furnace was filled with a mixture of corundum, coarsely-powdered charcoal and copper; and an iron lid lined with firebrick was luted in its place to exclude air. The charge was reduced by means of a 50-volt current from a 300-kilowatt dynamo, which was passed through the furnace for 1 1/2 hours till decomposition was complete. About 100 lb of bronze, containing from 15 to 20 lb of aluminium, were obtained from each run, the yield of the alloy being reported at about 1 lb per 18 e.h.p.-hours. The composition of the alloys thus produced could not be predetermined with exactitude; each batch was therefore analysed, a number of them were bulked together or mixed with copper in the necessary proportion, and melted in crucibles to give merchantable bronzes containing between 1 1/4 and 10% of aluminium. Although the copper took no part in the reaction, its employment was found indispensable, as otherwise the aluminium partly volatilized, and partly combined with the carbon to form a carbide. It was also necessary to give the fine charcoal a thin coating of calcium oxide by soaking it in lime-water, for the temperature was so high that unless it was thus protected it was gradually converted into graphite, losing its insulating power and diffusing the current through the lining and walls of the furnace. That this process did not depend upon electrolysis, but was simply an instance of electrical smelting or the decomposition of an oxide by means of carbon at the temperature of the electric arc, is shown by the fact that the Cowles furnace would work with an alternating current.

In 1883 R. Cratzel patented a useless electrolytic process with fused cryolite or the double chloride as the raw material, and in 1886 Dr E. Kleiner propounded a cryolite method which was worked for a time by the Aluminium Syndicate at Tyldesley near Manchester, but was abandoned in 1890. In 1887 A. Minet took out patents for electrolysing a mixture of sodium chloride with aluminium fluoride, or with natural or artificial cryolite. The operation was continuous, the metal being regularly run off from the bottom of the bath, while fresh alumina and flouride were added as required. The process exhibited several disadvantages, the electrolyte had to be kept constant in composition lest either fluorine vapours should be evolved or sodium thrown down, and the raw materials had accordingly to be prepared in a pure state. After prolonged experiments in a factory owned by Messrs Bernard Freres at St Michel in Savoy, Minet's process was given up, and at the close of the 19th century the Heroult-Hall method was alone being employed in the manufacture of aluminium throughout the world.

The original Deville process for obtaining pure alumina from bauxite was greatly simplified in 1889 by K. T. Bayer, whose improved process is exploited at Larne in Ireland and at Gardanne in France. New works on the same process have recently been erected near Marseilles. Crude bauxite is ground, lightly calcined to destroy organic matter, and agitated under a pressure of 70 or 80 lb per sq. in. with a solution of sodium hydroxide having the specific gravity 1.45. After two or three hours the liquid is diluted till its density falls to 1.23, when it is passed through filter-presses to remove the insoluble ferric oxide and silica. The solution of sodium aluminate, containing aluminium oxide and sodium oxide in the molecular proportion of 6 to 1, is next agitated for thirty-six hours with a small quantity of hydrated alumina previously obtained, which causes the liquor to decompose, and some 70% of the aluminium hydroxide to be thrown down. The filtrate, now containing roughly two molecules of alumina to one of soda, is concentrated to the original gravity of 1.45, and employed instead of fresh caustic for the attack of more bauxite; the precipitate is then collected, washed till free from soda, dried and ignited at about 1000 deg. C. to convert it into a crystalline oxide which is less hygroscopic than the former amorphous variety.

The process of manufacture which now remains to be described was patented during 1886 and 1887 in the name of C. M. Hall in America, in that of P. T. L. Heroult in England and France. It would be idle to discuss to whom the credit of first imagining the method rightfully belongs, for probably this is only one of the many occasions when new ideas have been born in several brains at the same time. By 1888 Hall was at work on a commercial scale at Pittsburg, reducing German alumina; in 1891 the plant was removed to New Kensington for economy in fuel, and was gradually enlarged to 1500 h.p.; in 1894 a factory driven by water was erected at Niagara Falls, and subsequently works were established at Shawenegan in Canada and at Massena in the United States. In 1890 also the Hall process operated by steam power was installed at Patricroft, Lancashire, where the plant had a capacity of 300 lb per day, but by 1894 the turbines of the Swiss and French works ruined the enterprise. About 1897 the Bernard factory at St Michel passed into the hands of

Messrs Pechiney, the machinery soon being increased, and there, under the control of a firm that has been concerned in the industry almost from its inception, aluminium is being manufactured by the Hall process on a large scale. In July 1888 the Societe Metallurgique Suisse erected plant driven by a 500 h.p. turbine to carry out Heroult's alloy process, and at the end of that year the Allgemeine Elektricitats Gesellschaft united with the Swiss firm in organizing the Aluminium Industrie Action Gesellschaft of Neuhasen, which has factories in Switzedand, Germany and Austria. The Societe Electrometallurgique Francaise, started under the direction of Heroult in 1888 for the production of aluminium in France, began operations on a small scale at Froges in Isere; but soon after large works were erected in Savoy at La Praz, near Modane, and in 1905 another large factory was started in Savoy at St Michel. In 1895 the British Aluminium Company was founded to mine bauxite and manufacture alumina in Ireland, to prepare the necessary electrodes at Greenock, to reduce the aluminium by the aid of water-power at the Falls of Foyers, and to refine and work up the metal into marketable shapes at the old Milton factory of the Cowles Syndicate, remodelled to suit modern requirements. In 1905 this company began works for the utilization of another water-power at Loch Leven.

In 1907 a new company, The Aluminium Corporation, was started in England to carry out the production of the metal by the Heroult process, and new factories were constructed near Conway in North Wales and at Wallsend-on-Tyne, quite close to where, twenty years before, the Alliance Aluminium Co. had their works.

The Heroult cell consists of a square iron or steel box lined with carbon rammed and baked into a solid mass; at the bottom is a cast-iron plate connected with the negative pole of the dynamo, but the actual working cathode is undoubtedly the layer of already reduced and molten metal that lies in the bath. The anode is formed of a bundle of carbon rods suspended from overhead so as to be capable of vertical adjustment. The cell is filled up with cryolite, and the current is turned on till this is melted; then the pure powdered alumina is fed in continuously as long as the operation proceeds. The current is supplied at a tension of 3 to 5 volts per cell, passing through 10 or 12 in series; and it performs two distinct functions: -- (1) it overcomes the chemical affinity of the aluminium oxide, (2) it overcomes the resistance of the electrolyte, heating the liquid at the same time. As a part of the voltage is consumed in the latter duty, only the residue can be converted into chemical work, and as the theoretical voltage of the aluminium fluoride in the cryolite is 4.0, provided the bath is kept properly supplied with alumina, the fluorides are not attacked. It follows, therefore, except for mechanical losses, that one charge of cryolite lasts indefinitely, that the sodium and other impurities in it are not liable to contaminate the product, and that only the alumina itself need be carefully purified. The operation is essentially a dissociation of alumina into aluminium, which collects at the cathode, and into oxygen, which combines with the anodes to form carbon monoxide, the latter escaping and being burnt to carbon dioxide outside. Theoretically 36 parts by weight of carbon are oxidized in the production of 54 parts of aluminium; practically the anodes waste at the same rate at which metal is deposited. The current density is about 700 amperes per sq. ft. of cathode surface, and the number of rods in the anode is such that each delivers 6 or 7 amperes per sq. in. of cross-sectional area. The working temperature lies between 750 deg. and 850 deg. C., and the actual yield is 1 lb of metal per 12 e.h.p. hours. The bath is heated internally with the current rather than by means of external fuel, because this arrangement permits the vessel itself to be kept comparatively cool; if it were fired from without, it would be hotter than the electrolyte, and no material suitable for the construction of the cell is competent to withstand the attack of nascent aluminium at high temperatures. Aluminium is so light that it is a matter requiring some ingenuity to select a convenient solvent through which it shall sink quickly, for if it does not sink, it short-circuits the electrolyte. The molten metal has a specific gravity of 2.54, that of molten cryolite saturated with alumina is 2.35, and that of the fluoride Al2F6.2NaF saturated with alumina 1.97. The latter therefore appears the better material, and was originally preferred by Hall; cryolite, however, dissolves more alumina, and has been finally adooted by both inventors.

Properties.

Aluminium is a white metal with a characteristic tint which most nearly resembles that of tin; when impure, or after prolonged exposure to air it has a slight violet shade. Its atomic weight is 27 (26.77, H=I, according to J. Thomson). It is trivalent. The specific gravity of cast metal is 2.583, and of rolled 2.688 at 4 deg. C. It melts at 626 deg. C. (freezing point 654.5 deg. , Heycock and Neville). It is the third most malleable and sixth most ductile metal, yielding sheets 0.000025 in. in thickness, and wires 0.004 in. in diameter. When quite pure it is somewhat harder than tin, and its hardness is considerably increased by rolling. It is not magnetic. It stands near the positive end of the list of elements arranged in electromotive series, being exceeded only by the alkalis and metals of the alkaline earths; it therefore combines eagerly, under suitable conditions, with oxygen and chlorine. Its coefficient of linear expansion by heat is 0.0000222 (Richards) or 0.0000231 (Roberts Austen) per 1 deg. C. Its mean specific heat between 0 deg. and 100 deg. is 0.227, and its latent heat of fusion 100 calories (Richards). Only silver, copper and gold surpass it as conductors of heat, its value being 31.33 (Ag= 100, Roberts-Austen). Its electrical conductivity, determined on 99.6% metal, is 60.5% that of cooper for equal volumes, or double that of copper for equal weights, and when chemically pure it exhibits a somewhat higher relative efficiency. The average strength of 98% metal is approximately shown by the following table:--

Elastic limit, Ultimate strength, Reduction tons per sq. in. tons per sq. in. of Area % Cast . . . 3 7 15 Sheet . . . 5 1/2 11 35 Bars . . . 6 1/2 12 40 Wire . . . 7-13 13-29 60

Weight for weight, therefore, aluminium is only exceeded in tensile strength by the best cast steel, and its own alloy, aluminium bronze. An absolutely clean surface becomes tarnished in damp air, an almost invisible coating of oxide being produced, just as happens with zinc; but this film is very permanent and prevents further attack. Exposure to air and rain also causes slight corrosion, but to nothing like the same extent as occurs with iron, copper or brass. Commercial electrolytic aluminium of the best quality contains as the average of a large number of tests, 0.48% of silicon and 0.46% of iron, the residue being essentially aluminium itself. The metal in mass is not affected by hot or cold water, the foil is very slowly oxidized, while the amalgam decomposes rapidly. Sulphuretted hydrogen having no action upon it, articles made of it are not blackened in foggy weather or in rooms where crude coal gas is burnt. To inorganic acids, except hydrochloric, it is highly resistant, ranking well with tin in this respect; but alkalis dissolve it quickly. Organic acids such as vinegar, common salt, the natural ingredients of food, and the various extraneous substances used as food preservatives, alone or mixed together, dissolve traces of it if boiled for any length of time in a chemically clean vessel; but when aluminium utensils are submitted to the ordinary routine of the kitchen, being used to heat or cook milk, coffee, vegetables, meat and even fruit, and are also cleaned frequently in the usual fashion, no appreciable quantity of metal passes into the food. Moreover, did it do so, the action upon the human system would be infinitely less harmful than similar doses of copper or of lead.

The highly electro-positive character of aluminium is most important. At elevated temperatures the metal decomposes nearly all other metallic oxides, wherefore it is most serviceable as a metallurgical reagent. In the casting of iron, steel and brass, the addition of a trifling proportion (0.005%) removes oxide and renders the molten metal more fluid, causing the

finished products to be more homogeneous, free from blow-holes and solid all through. On the other hand, its electro-positive nature necessitates some care in its utilization. If it be exposed to damp, to sea-water or to corrosive influences of any kind in contact with another metal, or if it be mixed with another metal so as to form an alloy which is not a true chemical compound, the other metal being highly negative to it, powerful galvanic action will be set up and the structure will quickly deteriorate. This explains the failure of boats built of commercially pure aluminium which have been put together with iron or copper rivets, and the decay of other boats built of a light alloy, in which the alloying metal (copper) has been injudiciously chosen. It also explains why aluminium is so difficult to join with low-temperature solders, for these mostly contain a large proportion of lead. This disadvantage, however, is often overestimated since in most cases other means of uniting two pieces are available.

Alloys.

The metal produces an enormous number of useful alloys, some of which, containing only 1 or 2% of other metals, combine the lightness of aluminium itself with far greater hardness and strength. Some with 90 to 99% of other metals exhibit the general properties of those metals conspicuously improved. Among the heavy alloys, the aluminium bronzes (Cu, 90-97.5%; Al, 10-2.5%) occupy the most important position, showing mean tensile strengths increasing from 20 to 41 tons per sq. in. as the percentage of aluminium rises, and all strongly resisting corrosion in air or sea-water. The light copper alloys, in which the proportions just given are practically reversed, are of considerably less utility, for although they are fairly strong, they lack power to resist galvanic action. This subject is far from being exhausted, and it is not improbable that the alloy-producing capacity of aluminium may eventually prove its most valuable characteristic. In the meantime, ternary light alloys appear the most satisfactory, and tungsten and copper, or tungsten and nickel, seem to be the best substances to add.

Uses.

The uses of aluminium are too numerous to mention. Probably the widest field is still in the purification of iron and steel. To the general public it appeals most strongly as a material for constructing cooking utensils. It is not brittle like porcelain and cast iron, not poisonous like lead-glazed earthenware and untinned copper, needs no enamel to chip off, does not rust and wear out like cheap tin-plate, and weighs but a fraction of other substances. It is largely replacing brass and copper in all departments of industry -- especially where dead weight has to be moved about, and lightness is synonymous with economy -- for instance, in bed-plates for torpedo-boat engines, internal fittings for ships instead of wood, complete boats for portage, motor-car parts and boiling-pans for confectionery and in chemical works. The British Admiralty employ it to save weight in the Navy, and the war-offices of the European powers equip their soldiers with it wherever possible, As a substitute for Solenhofen stone it is used in a modified form of lithography, which can be performed on rotary printing machines at a high speed. With the increasing price of copper, it is coming into vogue as an electrical conductor for uncovered mains; it is found that an aluminium wire 0.126 in. in diameter will carry as much current as a copper wire 0.100 in. in diameter, while the former weighs about 79 lb and the latter 162 lb per mile. Assuming the materials to be of equal tensile strength per unit of area -- hard-drawn copper is stronger, but has a lower conductivity -- the adoption of aluminium thus leads to a reduction of 52% in the weight, a gain of 60% in the strength, and an increase of 26% in the diameter of the conductor. Bare aluminium strip has recently been tried for winding-coils in electrical machines, the oxide of the metal acting as insulators between the layers. When the price of aluminium is less than double the price of copper aluminium is cheaper than copper per unit of electric current conveyed; but when insulation is necessary, the smaller size of the copper wire renders it more economical. Aluminium conductors have been employed on heavy work in many places, and for telegraphy and telephony they are in frequent demand and give perfect satisfaction. Difficulties were at first encountered in making the necessary joints, but these have been overcome by practice and experience.

Two points connected with this metal are of sufficient moment to demand a few words by way of conclusion. Its extraordinary lightness forms its chief claim to general adoption, yet is apt to cause mistakes when its price is mentioned. It is the weight of a mass of metal which governs its financial value; its industrial value, in the vast majority of cases, depends on the volume of that mass. Provided it be rigid, the bed-plate of an engine is no better for weighing 30 cwt. than for weighing 10 cwt. A saucepan is required to have a certain diameter and a certain depth in order that it may hold a certain bulk of liquid: its weight is merely an encumbrance. Copper being 3 1/3 times as heavy as aluminium, whenever the latter costs less than 3 1/2 times as much as copper it is actually cheaper. It must be remembered, too, that electrolytic aluminium only became known during the last decade of the 19th century. Samples dating from the old sodium days are still in existence, and when they exhibit unpleasant properties the defect is often ascribed to the metal instead of to the process by which it was won. Much has yet to be learnt about the practical qualities of the electrolytic product, and although every day's experience serves to place the metal in a firmer industrial position, a final verdict can only be passed after the lapse of time. The individual and collective influence of the several impurities which occur in the product of the Heroult cell is still to seek, and the importance of this inquiry will be seen when we consider that if cast iron, wrought iron and steel, the three totally distinct metals included in the generic name of ``iron'' -- which are only distinguished one from another chemically by minute differences in the proportion of certain non-metallic ingredients -- had only been in use for a comparatively few years, attempts might occasionally be made to forge cast iron, or to employ wrought iron in the manufacture of edge-tools. (E. J. R.)

Compounds of Aluminium. Aluminium oxide or alumina, Al2O3, occurs in nature as the mineral corundum (q.v.), notable for its hardness and abrasive power (see EMERY), and in well-crystallized forms it constitutes, when coloured by various metallic oxides, the gem-stones, sapphire, oriental topaz, oriental amethyst and oriental emerald. Alumina is obtained as a white amorphous powder by heating aluminium hydroxide. This powder, provided that it has not been too strongly ignited, is soluble in strong acids; by ignition it becomes denser and nearly as hard as corundum; it fuses in the oxyhydrogen flame or electric arc, and on cooling it assumes a crystalline form closely resembling the mineral species. Crystallized alumina is also obtained by heating the fluoride with boron trioxide; by fusing aluminium phosphate with sodium sulphate; by heating alumina to a dull redness in hydrochloric acid gas under pressure; and by heating alumina with lead oxide to a bright red heat. These reactions are of special interest, for they culminate in the production of artificial ruby and sapphire (see GEMS, ARTIFICIAL).

Aluminium Hydrates. -- Several hydrated forms of aluminium oxide are known. Of these hydrargillite or gibbsite, Al(OH)3, diaspore, AlO(OH), and bauxite, Al2O(OH)4, occur in the mineral kingdom. Aluminium hydrate, Al(OH)3, is obtained as a gelatinous white precipitate, soluble in potassium or sodium hydrate, but insoluble in ammonium chloride, by adding ammonia to a cold solution of an aluminium salt; from boiling solutions the precipitate is opaque. By drying at ordinary temperatures, the hydrate Al(OH)3.H2O is obtained; at 300 deg. this yields AlO(OH), which on ignition gives alumina, Al2O3. Precipitated aluminium hydrate finds considerable application in dyeing. Soluble modifications were obtained by Waiter Crum (Journ. Chem. Soc., 1854, vi. 216), and Thomas Graham (Phil. Trans., 1861, p. 163); the first named decomposing aluminium acetate from lead acetate and aluminium sulphate) with boiling water, the latter dialysing a solution of the basic chloride (obtained by dissolving the hydroxide in a solution of the normal chloride).

Both these soluble hydrates are readily coagulated by traces of a salt, acid or alkali; Crum's hydrate does not combine with dye-stuffs, neither is it soluble in excess of acid, while Graham's compound readily forms lakes, and readily dissolves when coagulated in acids.

In addition to behaving as a basic oxide, aluminium oxide (or hydrate) behaves as an acid oxide towards the strong bases with the formation of aluminates. Potassium aluminate, K2Al2O4, is obtained in solution by dissolving aluminium hydrate in caustic potash; it is also obtained, as crystals containing three molecules of water, by fusing alumina with potash, exhausting with water, and crystallizing the solution in vacuo. Sodium aluminate is obtained in the manufacture of alumina; it is used as a mordant in dyeing, and has other commercial applications. Other aluminates (in particular, of iron and magnesium), are of frequent occurrence in the mineral kingdom, e.g. spinel, gahnite, &c.

Salts of Aluminium. -- Aluminium forms one series of salts, derived from the trioxide, Al2O3. These exhibit, in certain cases, marked crystallographical and other analogies with the corresponding salts of chromium and ferric iron.

Aluminium fluoride, AlF3, obtained by dissolving the metal in hydrofluoric acid, and subliming the residue in a current of hydrogen, forms transparent, very obtuse rhombohedra, which are insoluble in water. It forms a series of double fluorides, the most important of which is cryolite (q.v.); this mineral has been applied to the commercial preparation of the metal (see above). Aluminium chloride, AlCl3, was first prepared by Oersted, who heated a mixture of carbon and alumina in a current of chlorine, a method subsequently improved by Wohler, Bunsen, Deville and others. A purer product is obtained by heating aluminium turnings in a current of dry chlorine, when the chloride distils over. So obtained, it is a white crystalline solid, which slowly sublimes just below its melting point (194 deg. ). Its vapour density at temperatures above 750 deg. corresponds to the formula AlCl3; below this point the molecules are associated. It is very hygroscopic, absorbing water with the evolution of hydrochloric acid. It combines with ammonia to form AlCl3.3NH3; and forms double compounds with phosphorus pentachloride, phosphorus oxychloride, selenium and tellurium chlorides, as well as with many metallic chlorides; sodium aluminium chloride, AlCl3.NaCl, is used in the production of the metal. As a synthetical agent in organic chemistry, aluminium chloride has rendered possible more reactions than any other substance; here we can only mention the classic syntheses of benzene homologues. Aluminium bromide, AlBr3, is prepared in the same manner as the chloride. It forms colourless crystals, melting at 90 deg. , and boiling at 265 deg. -270 deg. . Aluminium iodide, AlI3, results from the interaction of iodine and aluminium. It forms colourless crystals, melting at 185 deg. , and boiling at 360 deg. . Aluminium sulphide, Al2S3, results from the direct union of the metal with sulphur, or when carbon disulphide vapour is passed over strongly heated alumina. It forms a yellow fusible mass, which is decomposed by water into alumina and sulphuretted hydrogen. Aluminium sulphate Al(SO4)3, occurs in the mineral kingdom as keramohalite, Al2(SO4)3.18H2O, found near volcanoes and in alum-shale; aluminite or websterite is a basic salt, Al3(SO4)(OH)4.7H2O. Aluminium sulphate, known commercially as ``concentrated alum'' or ``sulphate of alumina,'' is manufactured from kaolin or china clay, which, after roasting (in order to oxidize any iron present), is heated with sulphuric acid, the clear solution run off, and evaporated. ``Alum cake'' is an impure product. Aluminium sulphate crystallizes as Al2(SO4)3.18H2O in tablets belonging to the monoclinic system. It has a sweet astringent taste, very soluble in water, but scarcely soluble in alcohol. On heating, the crystals lose water, swell up, and give the anhydrous sulphate, which, on further heating, gives alumina. It forms double salts with the sulphates of the metals of the alkalis, known as the alums (see ALUM.)

Aluminium nitride (AlN) is obtained as small yellow crystals when aluminium is strongly heated in nitrogen. The nitrate, Al(NO3)3, is obtained as deliquescent crystals (with 8H2O) by evaporating a solution of the hydroxide in nitric acid. Aluminium phosphates may be prepared by Precipitating a soluble aluminium salt with sodium phosphate. Wavellite Al8(PO4)3(OH)15.9H2O, is a naturally occurring basic phosphate, while the gem-stone turquoise (q.v.) is Al.(PO4).(OH)2.H2O, coloured by traces of copper. Aluminium silicates are widely diffused in the mineral kingdom, being present in the commonest rock-forming minerals (felspars, &c.), and in the gem-stones, topaz, beryl, garnet, &c. It also constitutes with sodium silicate the mineral lapis-lazuli and the pigment ultramarine (q.v..) Forming the basis of all clays, aluminium silicates play a prominent part in the manufacture of pottery and porcelain.

BIBLIOGRAPHY. -- The metallurgy and uses of aluminium are treated in detail in P. Moissonnier, L'Aluminium (Paris, 1903); in J. W. Richards, Aluminium (1896); and in A. Miner, Production of Aluminium, Eng. trans. by L. Waldo (1905); reference may also be made to treatises on general metallurgy, e.g. C. Schnabel, Handbook of Metalurgy, vol. ii. (1907). For the chemistry see Roscoe and Schlorlemmer, Treatise on Inorganic Chemistry, vol. ii. (1908); H. Moissan, Traite de chimie minerale; Abegg, Handbuch der anorgenischen Chemie; and O. Dammer, Handbuch der anorganischen Chemie. Aluminium alloys have been studied in detail by Guillet.

ALUNITE, or ALUMSTONE, a mineral first observed in the 15th century at Tolfa, near Rome, where it is mined for the manufacture of alum. Extensive deposits are also worked in Tuscany and Hungary, and at Bulladelah in New South Wales. By repeatedly roasting and lixiviating the mineral, alum is obtained in solution, and this is crystallized out by evaporation. Alunite occurs as seams in trachytic and allied volcanic rocks, having been formed by the action of sulphureous vapours on these rocks. The white, finely granular masses somewhat resemble limestone in appearance, and the more compact kinds from Hungary are so hard and tough that they are used for millstones. Distinct crystals of alunite are rarely met with in cavities in the massive material; these are rhombohedra with interfacial angles of 90 deg. 50', so that they resemble cubes in. appearance. Minute glistening crystals have also been found loose in cavities in altered rhyolite. The hardness is 4 and the specific gravity 2.6. The mineral is a hydrated basic aluminium and potassium sulphate, KAl3(SO4)2(OH)6. It is insoluble in water, but soluble in sulphuric acid. First called aluminilite by J. C. Delametherie in 1797, this name was contracted by F. S. Beudant in 1824 to alunite. (L. J. S.)

ALUR (Lur, Luri, Lurem), a Negro people of the Nile valley, living on the north-west coast of Albert Nyanza. They are akin to the Acholi (q.v.), speaking practically the same language.

ALURE (O. Fr., from aller, to walk), an architectural term for an alley, passage, the water-way or flat gutter behind a parapet, the galleries of a clerestory, sometimes even the aisle itself of a church. The term is sometimes written valure or valoring.

ALVA, or ALBA, FERNANDO ALVAREX DE TOLEDO, DUKE OF, (1508-1583), Spanish soldier, descended from one of the most illustrious families in Spain, was born in 1508. His grandfather, Ferdinand of Toledo, educated him in military science and politics; and he was engaged with distinction at the battle of Pavia while still a youth. Selected for a military command by Charles V., he took part in the siege of Tunis (1535), and successfully defended Perpignan against the dauphin of France. He was present at the battle of Muhlberg (1547), and the victory gained there over John of Saxony was due mainly to his exertions. He took part in the subsequent siege of Wittenberg, and presided at the court-martial which tried the elector and condemned him to death. In 1552 Alva was intrusted with the command of the army intended to invade France, and was engaged for several months in an unsuccessful siege of Metz. In consequence of the success of the French arms in Piedmont, he was made commander-in-chief of all the emperor's forces in Italy, and at the same time invested with unlimited power. Success did not, however, attend his first attempts, and after several unfortunate attacks he was obliged to retire into winter quarters. After the

abdication of Charles he was continued in the command by Philip II., who, however, restrained him from extreme measures. Alva had subdued the whole Campagna and was at the gates of Rome, when he was compelled by Philip's orders to negotiate a peace. One of its terms was that the duke of Alva should in person ask forgiveness of the haughty pontiff whom he had conquered. Proud as the duke was by nature, and accustomed to treat with persons of the highest dignity, he confessed his voice failed him at the interview and his presence of mind forsook him. Not long after this (1559) he was sent at the head of a splendid embassy to Paris to espouse, in the name of his master, Elizabeth, daughter of Henry, king of France. In 1567, Philip, who was a bigoted Catholic, sent Alva into the Netherlands at the head of an army of 10,000 men, with unlimited powers for the extirpation of heretics. When he arrived he soon showed how much he merited the confidence which his master reposed in him, and instantly erected a tribunal which soon became known to its victims as the ``Court of Blood,'' to try all persons who had been engaged in the late commotions which the civil and religious tyranny of Philip had excited. He imprisoned the counts Egmont and Horn, the two popular leaders of the Protestants, brought them to an unjust trial and condemned them to death. In a short time he totally annihilated every privilege of the people, and with unrelenting cruelty put multitudes of them to death. The executioner was employed in removing all those friends of freedom whom the sword had spared. In most of the considerable towns Alva built citadels. In the city of Antwerp he erected a statue of himself, which was a monument no less of his vanity than of his tyranny: he was figured trampling on the necks of two smaller statues, representing the two estates of the Low Countries. His attempt to raise money by imposing the Spanish alcabala, a tax of 5% on all sales, aroused the opposition of the Catholic Netherlands themselves. The exiles from the Low Countries, encouraged by the general resistance to his government, fitted out a fleet of privateers, and after strengthening themselves by successful depredations, ventured upon the bold exploit of seizing the town of Brielle. Thus Alva by his cruelty became the unwitting instrument of the future independence of the seven Dutch provinces. The fleet of the exiles, having met the Spanish fleet, totally defeated it, and reduced North Holland and Mons. Many cities hastened to throw off the yoke; while the states-general, assembling at Dordrecht, openly declared against Alva's government, and marshalled under the banners of the prince of Orange. Alva's preparations to oppose the gathering storm were made with his usual vigour, and he succeeded in recovering Mons, Mechlin and Zutphen, under the conduct of his son Frederick. With the exception of Zealand and Holland, he regained all the provinces; and at last his son stormed Naarden, and massacring its inhabitants, proceeded to invest the city of Haarlem, which, after standing an obstinate siege, was taken and pillaged. Their next attack was upon Alkmaar; but the spirit of desperate resistance was raised to such a height in the breasts of the Hollanders that the Spanish veterans were repulsed with great loss and Frederick constrained reluctantly to retire. Alva's feeble state of health and continued disasters induced him to solicit his recall from the government of the Low Countries; a measure which, in all probability, was not displeasing to Philip, who was now resolved to make trial of a milder administration. In December 1573 the much-oppressed country was relieved from the presence of the duke of Alva, who, returning home accompanied by his son, made the infamous boast that during the course of six years, besides the multitudes destroyed in battle and massacred after victory, he had consigned 18,000 persons to the executioner.

On his return he was treated for some time with great distinction by Philip. A tardy and imperfect justice, however, overtook him, when he was banished from court and confined in the castle of Uzeda for complicity in certain disgraceful conduct of his son. Here he had remained two years, when the success of Don Antonio in assuming the crown of Portugal determined Philip to turn his eyes towards Alva as the person in whose fidelity and abilities he could most confide. A secretary was instantly despatched to Alva to ascertain whether his health was sufficiently vigorous to enable him to undertake the command of an army. The aged chief returned an answer full of loyal zeal, and was immediately appointed to the supreme command in Portugal. It is a striking fact, however, that the liberation and elevation of Alva were not followed by forgiveness. In 1581 Alva entered Portugal, defeated Antonio, drove him from the kingdom, and soon reduced the whole under the subjection of Philip. Entering Lisbon he seized an immense treasure, and suffered his soldiers, with their accustomed violence and rapacity, to sack the suburbs and vicinity. It is reported that Alva, being requested to give an account of the money expended on that occasion, sternly replied, ``If the king asks me for an account, I will make him a statement of kingdoms preserved or conquered, of signal victories, of successful sieges and of sixty years' service.'' Philip deemed it proper to make no further inquiries. Alva, however, did not enjoy the honours and rewards of his last expedition, for he died in January 1583 at the age of 74.

AUTHORITIES. -- See the Life, by Rustant (Madrid, 1751). His correspondence during his Flemish government has been published by M. Gachard (Brussels, 1850). See also Coleccion de documentos ineditos para la historial de Espana, vols. iv., vii., viii., xiv., xaxii. and xxxv. (Madrid); and Motley's Rise of the Dutch Republic (1856).

ALVA, a police burgh of Clackmannanshire, Scotland, 3 1/2 m. N. of Alloa, terminus of a branch line of the North British railway. Pop. (1891) 5225; (1901) 4624. It is situated at the foot of three front peaks of the Ochils -- West Hill (1682 ft.), Middle Hill (1436 ft.) and Wood Hill (1723 ft.). There are spinning-mills, and manufactures of tweeds, tartans and other woollen goods. Silver, lead and other metals have been found in the hills, but not in paying quantities. The glen to the east of the town, in which are abandoned workings, is called the Silver Glen. Alva House is the seat of the Johnstones, a family which has been intimately connected with the district since the latter half of the 18th century.

ALVARADO, PEDRO DE (1495-1541), one of the Spanish leaders in the discovery and conquest of America, was born at Badajoz about 1495. He held a command in the expedition sent from Cuba against Yucatan in the spring of 1518, and returned in a few months, bearing reports of the wealth and splendour of Montezuma's empire. In February 1519 he accompanied Hernando Cortes in the expedition for the conquest of Mexico, being appointed to the command of one of the eleven vessels of the fleet. He acted as Cortes's principal officer, and on the first occupation of the city of Mexico was left there in charge. When the Spaniards had temporarily to retire before the Mexican uprising, Alvarado led the rear-guard (1st of July 1520), and the Salto de Alvarado -- a long leap with the use of his spear, by which he saved his life -- became famous. He was engaged (1523-24) in the conquest of Guatemala, of which he was subsequently appointed governor by Charles V. In 1534 he attempted to bring the province of Quito under his power, but had to content himself with the exaction of a pecuniary indemnity for the expenses of the expedition. During a visit to Spain, three years later, he had the governorship of Honduras conferred upon him in addition to that of Guatemala. He died in Guatemala in 1541.

ALVAREZ, FRANCISCO (c. 1465-1541?), Portuguese missionary and explorer, was born at Coimbra. He was a chaplain- priest and almoner to Dom Manuel, king of Portugal, and was sent in 1515 as secretary to Duarte Galvao and Rodrigo da Lima on an embassy to the negus of Abyssinia (Lebna Dengel Dawit (David) II.). The expedition having been delayed by the way, it was not until 152O that he reached Abyssinia, where he remained six years, returning to Lisbon in 1526-1527. In 1533 he was sent to Rome on an embassy to Pope Clement VII. The precise date of his death, like that of his birth, is unknown, but it must have been later than 1540, in which year he published at Lisbon under the king's patronage an account of his travels in one volume folio, entitled Yerdadera Informacam das terras do Preste Joam. This curious work was translated into Italian (G. B. Ramusio, Navagationi, vol. i., Venice, 1550); into

Spanish (Historia de las Cosas de Etiopia, by Fray Thomas de Padilla, Antwerp, 1557); into French (Historiale Description de l'Ethiopie, Christ. Plantin, Antwerp, 1558); into German (Wahrhaftiger Bericht von ... Ethiopien, Eisieben, 1566); into English (Sam. Purchas, Pilgrimes, part ii., London, 1625). The information it contains must, however, be received with caution, as the author is prone to exaggerate, and does not confine himself to what came within his own observation.

ALVAREZ, DON JOSE (1768-1827), Spanish sculptor, was born at Priego, in the province of Cordova, in 1768. His full name was Jose Alvarez de Pereira y Cubero. Bred to his father's trade of a stone-mason, he devoted all his spare time to drawing and modelling. His education in art was due partly to the teaching of the French sculptor Verdiguier at Cordova, and partly to lessons at Madrid, where he attended the lectures of the academy of San Fernando. In 1799 he obtained from Charles IV. a pension of 12,000 reals to enable him to visit Paris and Rome. In the former city he executed in 1804 a statue of Ganymede, which placed him at once in the front rank of the sculptors of his time, and which is now in the sculpture gallery of the Prado. Shortly afterwards his pension was more than doubled, and he left Paris for Rome, where he remained till within a year of his death. He had married in Paris Elizabeth Bougel, by whom he had a son in 1805. This son, known as Don Jose Alvarez y Bougel, also distinguished himself as a sculptor and a painter, but he died at Burgos before he had reached the age of twenty-five, a little more than two years after his father's death in Madrid in 1827. One of the most successful works of the elder Alvarez was a group representing Antilochus and Memnon, which was commissioned in marble (1818) by Ferdinand VII., and secured for the artist the appointment of court-sculptor. It is now in the museum of Madrid. He also modelled a few portrait busts (Ferdinand VII., Rossini, the duchess of Alba), which are remarkable for their vigour and fidelity.

ALVAREZ, DON MANUEL (1727--1797), Spanish sculptor, was born at Salamanca. He followed classical models so closely that he was styled by his countrymen El Griego, ``The Greek.'' His works, which are very numerous, are chiefly to be found at Madrid.

ALVARY, MAX (1858-1898), German singer, was born at Dusseldorf. Gifted with a fine tenor voice and handsome presence he speedily made a reputation in Germany in the leading roles in Wagnerian opera, and from 1885 onwards appeared also in America and England. He was at his best in 1892, when his performances as Tristan and Siegfried at Covent Garden aroused great enthusiasm.

ALVEARY (from the Lat. alvearium), a beehive; used, like apiarium in the same sense, figuratively for a collection of hard-working people, or a scholarly work (e.g. dictionary) involving bee-like industry. By analogy the term is used for the hollow of the ear, where the wax collects.

ALVENSLEBEN, CONSTANTIN VON (1809-1892), Prussian general, was born on the 26th of August 1809 at Eichenbarleben in Prussian Saxony, and entered the Prussian guards from the cadet corps in 1827. He became first lieutenant in 1842, captain in 1849, and major on the Great General Staff in 1853, whence after seven years he went to the Ministry of War. He was soon afterwards promoted colonel, and commanded a regiment of Guard infantry up to 1864, when he became a major-general. In this rank he commanded a brigade of guards in the war of 1866. At the action of Soor (Burkersdorf) on the 28th of June he distinguished himself very greatly, and at Koniggratz, where he led the advanced guard of the Guard corps, his energy and initiative were still more conspicuous. Soon afterwards he succeeded to the command of his division, General Hiller v. Gartringen having fallen in the battle; he was promoted lieutenant-general, and retained this command after the conclusion of peace, receiving in addition the order pour le merite for his services. In 1870, on the outbreak of war with France, von Alvensleben succeeded Prince Frederick Charles in command of the III army corps which formed part of the II German Army commanded by the prince. Under their new general, the Brandenburg regiments forming the III corps proved themselves collectively the best in the whole German army, with the possible exception of the Prussian guards, and, if Prince Frederick Charles is entitled to the chief credit in training the III corps, Alvensleben had contributed in almost equal degree to the efficiency of the Guard infantry, while his actual leadership of the III corps in the battles of 1870 and 1871 showed him afresh as a fighting general of the very first rank. The battle of Spicheren, on the 6th of August, was initiated and practically directed throughout by him, and in the confusion which followed this victory, for which the superior commanders were not prepared, Alvensleben showed his energy and determination by resuming the advance on his own responsibility. This led to the great battles of the 14th, 16th and 18th of August around Metz, and again the III corps was destined, under its resolute leader, to win the chief credit. Crossing the Moselle the instant that he received permission from his army commander to do so, Alvensleben struck the flank of Bazaine's whole army (August 16th) in movement westward from Metz. The III corps attacked at once, and for many hours bore the whole brunt of the battle at Vionville. By the most resolute leading, and at the cost of very heavy losses, Alvensleben held the whole French army at bay while other corps of the I and II German Armies gradually closed up. In the battle of Gravelotte, on the 18th, the corps took little part. Its work was done, and it remained with the II Army before Metz until the surrender of Bazaine's army. Prince Frederick Charles then moved south-west to co-operate with the grand-duke of Mecklenburg on the Loire. At the battle of Beaune-la-Rolande, the corps, with its comrades of Vionville, the X corps under General