Allocution. Address made by the Pope, in Latin, to the Cardinals, on some matter of special ecclesiastical moment. Allodial Tenure. That ownership of land which is absolutely free from feudal obligation. In most of the U. S. all lands are declared allodial, and feudal tenures are abolished. Allœogenesis. Heterogenesis in the third sense. Allæorgan. See ALLOPLAST.

Allogamy. Cross fertilization of flowers, the pollen from one flower acting on the pistils of another of the same species. See XENOGAMY and GEITONOGAMY.

Allogenesis. See METAGENESIS.

Allon, HENRY, D.D., 1818-1892. Pastor in London from 1844. Editor British Quarterly Review from 1865.

Allopathy. Name applied by Hahnemann to the school of medicine which rejected his views, on account of his belief that the remedies used by it caused symptoms different from those of the disease being treated. For some time the term was used to include all who disbelieved in homoeopathy, but now it has lost its significance and is little used. Compare MEDICINE. Alloplast. Meride composed of tissues, i.e., of more than one sort of cells, among which physiological division of labor obtains; also called heteroplast.

Allopola. Heterostaura having the poles of the dorsoventral axis unlike; Haeckel's promorphological term for animals having bilateral symmetry. Also called Zeugita, Centripipeda, etc. They are properly related to a sagittal plane rather than to a single axis. There are two groups; the Amphipleura, as in some of the irregular sea-urchins, and the Zygopleura, as in the Vertebrata, Vermes, Arthropoda, Mollusca, etc. The latter again constitute two groups, the Tetrapleura and Deplura.

Allori, CRISTOFANO, 1577-1621. Florentine painter of the decadence period, influenced by Bronzino; remembered for his magnificent and widely known picture of Judith, in the Pitti Gallery; his works otherwise inconspicuous.-His father ALESSANDRO, 1535-1607, was a well-known artist.

Allostaura. Homopola with biradiate symmetry, as seen in some Sadiolaria, e.g. Amphilonche.

Allotments. Small portions of land, not connected with any dwelling-house, leased to agricultural or other laborers for cultivation in addition to their other occupation, frequently by the Government, without the owner's consent.

Allotropy. Occurrence of a substance in two different forms. Carbon and phosphorus, e. g., are both met in allotropic forms. Ozone is allotropic oxygen, physically denser and chemically more active than oxygen itself. Carbon occurs in three different forms; the diamond, graphite and charcoal.

Allowable Actions. Deeds inconsistent with rigid maxims of morality, and yet, judged by the condition of human nature, not to be pronounced wrong; e. g., a lie told to save a friend's life must be acquiesced in, but only as an exception to the moral rule.

Alloxan. CH,N,O,. Prepared by the action of nitric acid upon uric acid; large prisms soluble in water. With sulphuretted hydrogen it gives alloxantine, from which the purple coloring matter murexide used to be prepared.

Alloy. Homogeneous mixture of two or more metals. While possessing some of the characteristics of chemical compounds, they are not regarded as true chemical compounds, but rather as mechanical mixtures, though definite chemical compounds occur in some alloys.

All Saints' Day. Festival originated ab. 610, and kept in the R. C. and English Churches on Nov. 1.

All Souls' Day. Festival of the Church of Rome, begun ab. 950, and kept Nov. 2 as a day of prayer for the dead.

Allspice. Pimenta officinalis, small tree of the Myrtle family, extensively cultivated in the West Indies for its fruit, which is used for flavoring food.

Allspice, CAROLINA. Shrubs of the genus Buettneria or Calycanthus, natives of the southern Alleganies; also known as Strawberry Shrub or Sweet-scented Shrub.

Allspice, WILD. See BENJAMIN BUSH.

Allston, WASHINGTON, 1779-1843. American painter, poet, and novelist. Monaldi, 1842. In art he was West's pupil, and was supposed to resemble Titian.

Alluvium. Fine soil that has been deposited by the action of water. Alluvial soils are easily worked and in general exceedingly fertile, though this depends somewhat upon the |

source of the alluvium; i.e., the character of the soil whence it was obtained. They are usually unhealthy locations, malarial diseases, dysentery and diarrhoea being prevalent.

Allyl Alcohol. CH2:CH.CH,OH. Bpt. 97°C. Hydrate of the allyl radical; liquid of suffocating odor, present in crude wood spirit, and therefore formed by the destructive distillation of wood, usually prepared by the abstraction of water from glycerine.

Allyl Compounds. Containing the unsaturated group CH,:CH.CH, in combination. They unite easily with bromine. Allylene. CH; C.CH,. Unsaturated hydrocarbon belonging to the acetylene series.

Allyl isosulphocyanate. CH,:CH.CH,.N:S C. Called also allyl mustard oil; liquid boiling at 151°C.; prepared by distilling black mustard seed with water. It has the pungent and distinctive odor of mustard.

Alma. River in the Crimea; scene of a battle, Sept. 20, 1854, between the Russians, 46,000 strong, and the English, French and Turkish armies, 57,000. The Russians were routed with a loss of 5,000; the allies lost 3,400.

Almaden. Town of Spain, near the Sierra Morena, noted for its mines of quicksilver. These were worked of old by the Iberians and Romans, leased to the Fuggers of Augsburg ab. 1550, and to the Rothschilds 1843. Pop. ab. 9,000. The A. mines of Santa Clara Co., Cal., opened 1846, were named from those of Spain.

Almagest. Arabic translation of Ptolemy's Suntaxis, pub. at Alexandria by Claudius Ptolemy, ab. 140. A collection of problems in geometry and astronomy, now noted as containing the earliest star catalogue. It was accepted for fourteen centuries as an undisputed authority on all astronomical matters.

Almagro, DIEGO D', 1475-1538. Conqueror, with Pizarro. of Peru in 1525, afterward Pizarro's enemy and victim. His son and namesake avenged him 1541, and was executed 1542.

Almanac. Book of tables published from year to year containing a calendar of days, weeks and months, a record of various astronomical phenomena, such as the times of rising and setting of the sun, moon, and other heavenly bodies, a

English Almanac, 17th Cent., Jan. to Mch.

register of ecclesiastical festivals and saints' days. In addition to these, a great variety of matter of a historical, statistical or astrological character is sometimes added.

Almandine, or ALMANDITE. (1) Variety of spinel. (2) Variety of garnet.

Almansa. Town of s. e. Spain; scene of a decisive victory gained Apr. 25, 1707. by the French under Berwick, over the allies of Charles III., who lost most of their infantry, with artillery and baggage. Nearly all Valencia and Aragon submitted to Philip V.

Alma-Tadema, LAURENZ, b. 1836. He was b. in Friesland, studied in Antwerp, and has lived in England since 1870. As a youth he conceived a passion for Egyptian and classic archæology, and has devoted himself as a painter almost exclusively to ancient subjects, in which field he has won worldwide reputation. His forte is painstaking minuteness of detail and fidelity to archæologic memoranda. To these aims he has sacrificed vigor and breadth of effect. In spite of his rather cold and rigid methods of execution he has distinct greatness as a colorist, and in popularity and financial success is among the first modern painters. His most important work in America is Reading Homer, shown at the Columbian Exposition. Here were also seen, in the English Exhibit, his masterpieces, A Dedication to Bacchus and The Sculpture Gallery.

Almeida, FRANCESCO D', ab. 1455-1510. Portuguese viceroy of India 1505-8.

Almeida-Garrett, JOAO BAPTISTA D', 1799-1854. Portuguese poet and novelist; minister to Belgium 1834, ennobled

1852.

Almeria. Ancient Moorish city and seaport of Spain, on the gulf of Almeria, an arm of the Mediterranean. Pop., 1885, 38.378.

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Alphæus. Disciple of Christ (some think his uncle by marriage), father of St. James the Less.

Alpheus. River of Arcadia and Elis, flowing underground a part of the way. In mythology, a river-god who pursued the nymph Arethusa under the sea to her fountain in an island near Syracuse.

Alpine Club. Association of 500 or more Englishmen, who undertake expeditions in the high Alps for pleasure and scientific advantage; founded 1858. Another, in America, dates from 1873.

Alpine Railways. Swiss mountain railways have usually a gauge of one meter (3.28 feet). On steep grades cables and rack rails are used. Railways have been built up the Eiger, Stauserhorn, and other peaks, while others are projected or under construction. Water ballast is used as a motive power in many cases.

Alpino, PROSPERO, 1553-1617. Italian botanist. De plantis Aegypti liber, 1592; De plantis exoticis, 1627.

Alps. System of mountains of s. Europe, the highest, most extensive and complicated except the Caucasus. It sweeps around the northern end of Italy in a broad curve, occupying s. e. France, all Switzerland, Italy, and s. w. Austria, to the north frontier of Turkey. The system is often subdivided as follows: the region adjoining the boundary between France and Italy, extending from the Mediterranean n. to Mont Blanc and having a n. and s. trend is in three parts, known respectively, beginning at the sea, as the Maritime, Cottian, and Graian Alps. That part east of Mont Blanc, having an e. and w. trend, is separated into two groups of ranges, a northern and a southern. The first comprises the Bernese Alps, n. of the Rhone, the Alps of St. Gall, n. w. of the Rhine, the Noric, extending from Lake Constance to the Kahlenburg in w. Austria, and the Styrian, between the Noric and the Carnic. The latter comprise the Pennine Alps, between Mont Blanc and Monte Rosa, the Lepontine, extending from Monte Rosa to the sources of the Rhine; the Rhoetian, which extend to the sources of the Piave; and the Carnian, which form the frontier between Italy and Austria. The Dinaric Alps, which extend southeast down the east coast of the Adriatic, complete the system. The highest part is in Switzerland and adjacent regions of France and Italy. Here are found Mt. Blanc, the

Valley of Chamouni and Mt. Blanc.

highest summit, 15.810 ft.. Monte Rosa, 15,208 ft., and the Finster Aarhorn, 14.026 ft. Of the passes, Monte Cenis has an altitude of 6775 ft., the Simplon 6592 ft., the Splügen 6935 ft., Great St. Bernard 8150 ft., and St. Gothard 6976 ft.

The mass of the Alps is composed of granite, gneiss, and other metamorphic rocks, with stratified beds upturned upon their flanks. The snow line is at an altitude of ab. 8900 ft., and glaciers descend to a level of 3400 ft. It is estimated that 1500 sq. miles are covered with snow and ice in these mountains.

Alquifoux. PbS. Coarse-grained galenite, sometimes called potters' ore from its being used in glazing earthenware.

Alsace. Part of ancient Gaul, held by the Romans nearly 500 years; then by Franks and French monarchs till Otho I., when it became German, and by Austria 1273-1648, when much of it was ceded to France. Louis XIV. took forcible possession of nearly all the rest. It was held by France for two centuries, and reunited to Germany 1871, except a small district.

Alsace-Lorraine. Province of the German empire, ceded by France 1871. Area, 5,668 sq. m. Pop., 1890, 1,603,506, of whom ab. one-eighth are of French origin. It sends 15 representatives to the Reichstag. More than three-fourths of the people are Catholics.

Alsatia. Sanctuary for debtors and law-breakers in White. friars, London, till 1697; described in Scott's Fortunes of Nigel Alsike. See CLOVER.

Al-Sirat. Narrow bridge believed by Mohammedans to stretch across hell from earth to paradise.

Altai Mountains. In Central Asia, between Siberia and n. w. China. Length ab. 1,000 m.; extreme ht., 12,790 ft. Altair, a AQUILE. Star of first magnitude, Right ascension, 19h. 45m. 22s. Declination, 8° 34' 32" n.

Altamaha. River of Georgia. It rises in the foot hills of the Blue Ridge and flows s. and s. e. Drainage area 14,109 sq. m., length 155 m.

Altar. Table on which, in primitive religions, sacrifices and libations were offered. In Greek and Roman, as well as in Jewish antiquity, it had an important part in the worship of the temple. Vitruvius gives rules for the position and construction of altars, which differ in magnitude and form according to the deities to whose service they are consecrated. In Christian

worship, though the sacrifice became merely emblematic and typical, in Gothic architecture, the high altar became the central object of the church or cathedral, and was elaborately decorated.

Altar of Burnt-Offering. Among the Hebrews, the great altar, placed before the Tabernacle, afterward before the Temple, used for bloody sacrifices, and other oblations. In the Temple, entirely of brass, 20 cubits long, 10 high.

Altar of Incense. Among the Hebrews, made of acaciawood, overlaid with gold, with four projecting horns, a cubit long and broad, and two cubits high. It stood in the Holy Place.

Altazimuth. Astronomical instrument used to indicate ALTITUDE (q. v.) and AZIMUTH (q. v.) of any heavenly body. The most important altazimuth is at Greenwich.

Altdorfer, ALBRECHT, 1488-1538. German painter, alderman and official architect at Ratisbon; a leader of the school dominated by Dürer. His Victory of Alexander the Great over Darius in Munich is one of his finest works.

Altenesch, BATTLE OF, 1234. Frisian Stedingers overpow ered by 40,000 crusaders, instigated by Conrad of Marburg.

Alteratives. Group of medicines which are believed to alter condition of diseased tissues without their method of action being known. More exact methods of investigation have reduced their number. Mercury, iodine and its compounds, and arsenic, are the most prominent drugs included in this group.

Alternant. Determinant in which the elements of each row are functions of one variable and each column contains like functions of a different variable.

Alternate. In Botany, contradistinction to opposite; e. g., leaves placed singly at the nodes; and, generally, petals and sepals of flowers.

Alternate Angles. Plane, spherical or dihedral; formed by a transversal with two lines or planes on opposite sides of the transversal and of the two lines or planes involved.

Alternate Function. One which changes its sign when two of its elements are interchanged; name used by Cauchy for quantities now called "Determinants."

Alternate Numbers. Formed by adding "n" numbers such that, the units of any two terms being multiplied, interchange of position of the factors changes the sign of the product. Like change of sign results with alternate numbers

themselves.

alternate directions. Such a current may be produced by the Alternating Current. Succession of electric impulses in passage of a conductor to and fro through a positive or a negative magnetic field, or by the continuous motion of a conductor through magnetic fields of opposite polarities. In alternating dynamos the "frequency" may vary from twenty or thirty to many hundred in a second.

Alternation. Change of order between the second and third terms of a proportion.

If A: B: C: D, by alternation

A: C: B: D.

Also used, though rarely, for permutation.

Alternation of Generations. Mode of reproduction in which offspring differs from parent in mode of origin, or in form, or both, and in its turn the child produces offspring that resembles the grandparent; or the child may produce offspring like itself for several generations, but eventually the original form reappears. In the Hydroids the jellyfish first appears as buds on a plant-shaped colony of hydra-like zoöids; the egg of the jellyfish produces a hydra which, by budding again and again, restores the original stock with medusa-buds on it, that are in turn detached as separate animals that reproduce sexually by means of eggs. Such a typical case presents a series of non-sexual (asexual) generations, alternating with a sexual generation. In Plant-lice, we have a series of parthenogenetic summer-generations alternating with sexed generations that appear in the fall. See PARTHENOGENESIS, AMPHIGENESIS, METAGENESIS, HYPOGENESIS and STROPHOGENESIS.

Althæa. Genus of Mallow family. The so-called Shrubby Althæa is Hibiscus Syriacus, a tall shrub, native of western Asia, and much cultivated; known also as Rose of Jericho. The root of Marsh-mallow, Althaea officinalis, is used in medicine for

Alto. Strictly, the male voice of highest pitch in music; generally used as synonymous with contralto, the middle part in vocal harmony, sung by the low female voice. Also Italian name for the VIOLA (q. v.).

Alton. City of Madison Co., Ill., on the Mississippi, 22 m. n. of St. Louis. Pop., 1890, 10,294.

Altona. Largest city of Schleswig-Holstein, Germany; on n. bank of the Elbe, near Hamburg. Pop., 1890, 143,249. Altoona. City of Blair Co., Pa., at e. base of the Allegany plateau. It contains the principal offices and shops of the Pennsylvania Railroad. Pop., 1890, 30,337.

Alto-rilievo. High relief or bold projection in sculpture. Altranstädt, PRUSSIA, TREATY OF. Between Sweden and Poland; signed Oct. 4, 1706. Another, 1714, between France and Germany.

Altruism. Action or inclination prompted by the benevolent affections; desire of acting for the advantage of others, as opposed to egoism, desire of acting for our own advantage. Alula. See BASTARD WING.

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Alum Shale. Clay containing pyrite and peat; used for making ALUM (q.v.).

Alumina. See ALUMINIUM TRIOXIDE.

Aluminates. Class of compounds derived from aluminium hydroxide, Al(OH),, by replacing the hydrogen by a metal. Thus, when sodium hydroxide is added to a solution of an aluminium salt, aluminium hydroxide is first precipitated, but is redissolved in an excess of sodium hydroxide. The compound in solution is thought to be sodium aluminate. Al(ONa),. There are others of different composition, as A10.OK; Ca(AlO,). The most important which occur in nature are the spinels.

Aluminium. Al. Sp. gr. 2.7. Mpt. 625° C. At. wt. 27. Discovered by Wöhler 1827. It is soluble in hydrochloric acid; it is not acted upon by nitric or sulphuric acids at ordinary temperatures; at higher temperatures action takes place and the corresponding salts are formed. It dissolves in solutions of caustic alkalies, forming aluminates. It acts both as an acid-forming and a base-forming element. It reduces many oxides when heated with them to a sufficiently high temperature; for this reason it is used in the preparation of boron and silicon. See ALUMINIUM, METALLURGY OF.

Aluminium Acetate. Al(C,H,O,),. Used as a mordant in dyeing. It is usually made by treating a solution of alum with a solution of lead acetate, when lead sulphate is precipitated, and potassium and aluminium acetates remain in solution. It may also be made by treating aluminium sulphate with lead acetate. It is sold under the name of "red liquor."

Aluminium Bronze. Alloy of copper and aluminium, containing from 5 to 10 per cent of the latter. It resembles gold in color, is very hard and elastic. Ordinary reagents do not act upon it easily. It is used for cartridge-shells, gunbarrels, gun-linings, helmets, hold-down bolts for mortar batteries, propellers, and small boats.

Aluminium Chloride. AICI,. If aluminium hydroxide be treated with hydrochloric acid, aluminium chloride is formed, and crystallizes from the solution as AICI,.6H,O. If the attempt be made to drive off the water of crystallization, the compound is decomposed, leaving alumina as a residue. To make anhydrous aluminium chloride, chlorine is passed over a heated mixture of the oxide and carbon. The chloride is volatile and is deposited in the cool part of the apparatus. When exposed to the air it attracts moisture. Aluminium chloride boils at 180° C. With sodium chloride and potassium chloride it forms double salts of the composition AICI,.NaCl and AICI,.KCI.

Aluminium Fluoride. AlF,. Formed by the action of silicon fluoride upon aluminium. It forms cubic crystals which are insoluble in water and resist the action of acids. With sodium fluoride it forms a double compound. See CRYOLITE.

Aluminium Hydroxide. Al(OH),. It occurs as the mineral HYDRARGILLITE (q.v.). In the laboratory it is made by treating a solution of aluminium chloride with ammonia solution; formed in this way, it is a white, gelatinous precipiminic acid, AIO.OH. A compound of the same composition tate, which loses water on being heated, forming meta-aluoccurs in nature as the mineral DIASPORE (q.v.). If heated higher, aluminium trioxide, Al,O,, is formed. In addition to these two hydroxides there is a third, Al,O(OH),. The normal hydroxide is the starting point in the preparation of the other aluminium salts.

Aluminium, METALLURGY OF. Beauxite is the chief ore source of aluminium, and it occurs in France, in Austria, Ireland, Arkansas, Alabama and Georgia. It consists of aluminium oxide, water, iron oxide and silica, the last two as impurities. The market price varies from $6 to $10 a ton for ore containing 60 to 80 per cent of alumina, corresponding to 30 to 45 per cent of aluminium. The 900 pounds of aluminium in a ton of $10 beauxite is worth about $500, when extracted, the great difference in the values of finished and raw material representing mainly the costly process of manufacture.

Aluminium compounds are very difficult to reduce to metal, resisting all the ordinary reducing agents. The German chemist Wöhler first obtained the metal as a powder in 1827, by decomposing the chloride by potassium; it resisted all attempts to melt it. The French savant Deville first produced it in large quantities, in 1855; his method being to reduce the double chloride of aluminium and sodium by sodium. The cost of production by this process was ab. $10 per pound, and it was used exclusively up to 1885. In 1886 electrical methods began to be operated on a commercial scale, and since 1890 have entirely supplanted the sodium process. The present method is as follows: Pure alumina is first prepared from beauxite, by roasting the fine ore mixed with soda ash in a furnace, washing out the combination of soda and alumina with water, and precipitating aluminium hydroxide from this solution by carbonic

41

acid gas. The precipitate is filtered out, washed, dried and calcined, and is introduced into a molten bath of fused cryolite, fluorides of aluminium and sodium, which dissolves about 20 per cent of its weight of alumina. On passing an electric current through this bath only the dissolved alumina is decomposed, it being the weakest chemical compound present. while the fluorides constituting the solvent portion of the bath remain undecomposed. The operation is carried on in a wroughtiron tank, 6 feet long, 3 feet wide and 2 feet deep, lined heavily with carbon. The fluid bath is 1 foot deep, and carbon cylinders dipping into it from above form the positive electrode, while the lining of the pot forms the negative pole. The distance of the carbon cylinders from the bottom is so regulated that the heat set free by the resistance to the passage of the current is sufficient to maintain the bath in fusion without the aid of external heat. When the alumina dissolved in the bath has been mostly decomposed, the current begins to attack the fluorides, forming the solvent, and sets free irritating fumes of carbon fluoride. To avoid this, the bath is kept well supplied with alumina. The metal accumulating at the bottom of the bath is periodically bailed out with ladles. The process is thus made continuous, a pot sometimes running several months without stopping. Each pot requires an electrical tension of 5 to 8 volts to operate it, and the output averages one pound of metal per day for every horse-power employed to generate the electricity. The purity of the metal depends mostly on the purity of the alumina used, for any iron oxide or silica in it would inevitably be reduced and pass into the metal as iron and silicon. Raw beauxite is sometimes employed instead of pure alumina, to produce a low grade suitable for some purposes. The cost of production, with not over 2 per cent of impurities, is between 30 and 40 cts. a pound. The largest works in the world are at the Falls of the Rhine, Switzerland, their annual output being over a million pounds. The only works in America are at New Kensington, Pa., on the Allegany River, 18 m. above Pittsburg; their yearly output is half a million pounds. This firm is building a 6.000 horse-power plant at Niagara Falls, which will have a yearly capacity of two million pounds, and will be in operation in 1895. The present annual production in the world is two million pounds, and will probably reach double that quantity in 1895.

The color of aluminium is white with a shade of blue, especially in impure metal. Pure metal is about the same in softness and toughness as pure copper; under the knife-blade it cuts smoothly. A small proportion of impurity hardens it considerably and makes it cut gritty. In specific gravity it is by far the lightest of the useful metals, being 2.6 to 2.7; the specific heat is high, 0.222, and the melting point is 625° C., a dull-red heat. The latent heat is the greatest of any known substance, being 100 calories according to quite recent experiments; in virtue of this quantity, it takes considerable time to melt even in a hot fire. In conducting power for heat and electricity, it stands next after silver, copper and gold. In malleability it is but little inferior to gold and silver, the leaf having almost entirely displaced silver leaf; its ductility is likewise remarkable. In short, it stands in many physical properties intermediate between the noble and the so-called base metals.

Pure aluminium is, like pure gold and pure silver, soft and not strong; but, like them, it may be hardened and strengthened by judicious alloying. From 1 to 5 per cent of silver, copper, nickel, zinc, or titanium effects this improvement, raising the tensile strength 50 or 100 per cent, as the following

table shows:

These strong, light alloys replace the pure metal for purposes requiring hardness, strength and rigidity, such as portable instruments and vehicles of every description, etc. On account of its rapid conduction of heat, lightness and non-poisonous properties, it is the best material known for culinary utensils, The use of these is increasing with great rapidity. Several hundred tons have been used in Germany for military equipments, such as ammunition cases, bayonet scabbards, shells, and drums. A few of the many other uses are surgical instruments, boats, pontoons, torpedo tubes, bicycles, watches, chains, horse-shoes, bitts, stirrups, pen-holders, match-boxes, etc. The most important alloys in which it is the minor constituent are those with copper, iron and zinc. Copper containing up to 10 per cent of aluminium forms the aluminium bronzes,

Aluminium-brass is ordinary brass with 1 to 2 per cent of aluminium. It is 50 per cent stronger than ordinary brass, and can be forged hot like soft iron. In the steel industry aluminium has found important application as a de-oxidizing agent, being added in small quantities to molten steel just before casting. The effect is to produce ingots or castings free from blow-holes. When added to a bath of molten zine, such as is used for galvanizing iron, it removes oxygen from the bath, prevents further oxidation of the zinc, and causes the zinc coating on the iron to be brighter and to keep its color better. Similar applications are made of its de-oxidizing powers in the metallurgy of iron and nickel.

Aluminium is sold in three grades: "extra" is over 99.5 per cent pure; ordinary "number one commercial" is guaranteed over 98 per cent pure; and “commercial number two" is guaranteed over 95 pure and averages 96 per cent. This last quality is used in steel works; the first two are sold either in ingots for re-melting or in slabs for rolling. The prices, Feb. 1895, were 98 per cent 53 cts.; 94 per cent 50 cts. per pound. Aluminium Nitrate. Al(NO,),. Made by dissolving aluminium hydroxide in nitric acid. It crystallizes in the form of Al(NO,),.9H,O, which fuses at 73° C. without decomposition; at 100° C. decomposition takes place. It is used in dyeing. Aluminium Sodium Fluoride. See CRYOLITE.

Aluminium Sulphate. Al(SO),.18H,O. Made by dissolving aluminium hydroxide in dilute sulphuric acid and evaporating to crystallization, when a salt of this composition is deposited. If heated to redness, it is decomposed, leaving a residue consisting mainly of aluminium trioxide. It is soluble in 2 parts of water, has a sweetish, astringent taste and an acid reaction. It is manufactured in large quantities for use as a mordant and for sizing paper, etc.

Aluminium Trioxide, or ALUMINA. Al,O,. Made by heating the hydroxide. It occurs in nature in the form of ruby, sapphire, and corundum. It can be fused with the oxyhydrogen flame, and on melting it becomes crystalline. Artificial rubies and sapphires have been made in this way by adding the proper coloring matter to the fused alumina. It is insoluble in acids if it has been heated strongly. It can be obtained in a soluble form by fusing with acid potassium sulphate. Beauxite is an impure form.

Alums. Class of compounds of the type represented by common alum, potassium aluminium sulphate, KAI(SO), 12 H,O. Other alums may be regarded as derived from this by replacing the potassium with sodium, ammonium, rubidium, lithium, silver, cæsium or thallium. Alums are also derived from the common form by substituting for the aluminium, iron, chromium or manganese. These all crystallize in octahedra modified by cubes, and are strictly isomorphous. They are all soluble in water and possess an astringent taste. The potassium and ammonium alums are used very extensively in dyeing. The former is employed in medicine as an astringent, as a styptic, and as an application to unhealthy suppurating surfaces, especially when deprived of its water of crystallization (burnt alum); it is also emetic in large doses, and is used to relieve the colic of lead poisoning. Added to bread it whitens it, rendering possible the use of inferior grades of flour, and increases its weight by absorbing appreciable amounts of moisture. Bread adulterated in this manner is unfit for use, as the alum soon disturbs the digestion and causes constipation.

Alunite, or ALUMSTONE. K,A1,4SO,.6H2O. Natural hydrous sulphate of aluminium and potassium, found in Italy, Hungary, and other European countries. It is a product of the action of sulphurous vapors on the rocks with which the mineral is associated. It has been used as a source of alum, which is obtained from the mineral by repeated roastings and washings. It was first observed at Tolfa, near Rome.

Alva, FERNANDO ÁLVAREZ De Toledo, DUKE OF. 1508-1583. Spanish general of Philip II.; governor of the Netherlands 156773; detested for his cruelties. By his own account, he had ordered some 18,000 executions, chiefly for religious cause. conquered Portugal 1580.

He

Pizarro in Peru; captain-general there 1549–53.
Alvarado, ALONZO. Follower of Cortez in Mexico and of

Alvarado, PEDRO DE, d. 1541. Officer of Cortez 1518; had command in city of Mexico 1520; gov. of Guatemala 1523, and also of Honduras 1535.

Alvarez, FRANCISCO. Portuguese priest who was in Abyssinia 1515-21, and pub. an account of it 1540.