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Arnheim. City of the Netherlands, on the Old Rhine. Pop., 1891, 50,194.

Arnica. Yellow-flowered plant of the Composite, Arnica montana, native of Europe and Asia. The officinal tincture is obtained from the flowers, and is used externally for wounds.

Arnica montana.

The various preparations of the root and flowers of this plant are largely used in domestic medicine, but are of little value, and must not be used indiscriminately, as severe headache. disturbed action of the heart, and other nervous phenomena have resulted from overdoses.

Arnim, LUDGWIG JOACHIM VON, 1781-1831. German poet and novelist. Crown Guardians, 1817.-His wife, BETTINA (BRENTANO), 1785-1859, corresponded as a child with Goethe, and tr. his letters, 1835. Die Günderode, 1840.

Arno. River of Italy, rising in the Apennines, and partly navigable to Florence.

Arnobius. Christian apologist, converted ab. 303. His Disputations against the Heathen were written soon after, and, it is said, as a condition of admission to church fellowship.

Arnold, BENEDICT, 1741-1801. American general. When in command at West Point, he offered to surrender to the enemy. The scheme failed by the arrest of André, while the traitor A. escaped and joined the British army.

Arnold, SIR EDWIN, b. 1832. English poet and journalist; knighted 1888. Light of Asia, 1879. Of late years he has written much about Japan.

Arnold, GEORGE, 1834-1865. American poet and humorist. Arnold, GOTTFRIED, 1666-1714. German pietist and hymnwriter. His Impartial Church History, 1699, apologizes for heretics.

Arnold, LAUREN BRIGGS, 1814-1888. American agricultural and dairy investigator; lecturer Cornell Univ. 1878-87. American Dairying, 1875.

Arnold, MATTHEW, LL.D., 1822-1888. English poet, critic and essayist; eldest son of DR. THOMAS; long Inspector of Schools; Prof. of Poetry at Oxford 1857-67. An elegant writer and a fearless thinker, he was the apostle of "sweetness and light." His Culture and Anarchy, 1869, St. Paul and Protestantism, 1870, Literature and Dogma, 1873, and other prose works have deeply influenced the religious thought of our time. Arnold, THOMAS, D.D., 1795-1842. English educator and author. History of Rome, 3 vols., 1838-42. As head-master of Rugby School from 1827, he trained some of the brightest minds in England, and earned the fame of a model teacher.

Arnold, OF BRESCIA, ab. 1100-1155. Italian reformer; pupil of Abelard, and condemned with him 1140. At Rome, 1146, he sought to restore the Republic. After much commotion, the city was put under an interdict; A.'s partisans deserted him; he was arrested by the Emperor Barbarossa, and executed. Arnot, WILLIAM, 1808-1875. Scottish divine. Proverbs, 185758; Parables, 1865.

Arnould, SOPHIE, 1744-1803. French singer and actress. Aromatic Compounds. Containing a nucleus of 6 carbon atoms united with each other in a closed ring or chain, and

changed into nitro compounds by nitric acid, sulphonic acids by sulphuric acid, and bromine compounds by the direct action of bromine; derived from benzene, C.H., by replacing the hydrogen by other elements or groups.

Aromatic Vinegar. Concentrated acetic acid, perfumed by some essential oil, as lavender, rosemary, or cloves. It is volatile and corrosive, and is used as a stimulant by smelling in headache and fainting.

Arpads. Dynasty of Arpad, Magyar leader, who d. 907; male line extinct 1301.

Arquebuse. Early form of musket with rudimentary trigger; successor of the gun which was fired by application of a slow-match to touch-hole. In the 16th century some

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great harquebuses" are said to have thrown balls of four to the pound.

Arques. In n. France; scene of a victory of Henry IV. over Mayenne and the League, Sept. 21, 1589.

Arrack. Spirituous liquor made in East Indies from rice, which is germinated, fermented and distilled. Some has molasses, or the distillate from the juice of the cocoanut, added to the mash.

Arran. Island of Scotland, one in the Frith of Clyde, area 165 sq. m.; three off Galway Bay, Ireland, 18 sq. m. Arras. Ancient city of n. France, famous in Middle Ages for its tapestry. It formerly belonged to the Low Countries, and was taken by storm or siege 1482 and 1640. Robespierre was b. here. Arrastre. Crude apparatus for grinding and amalgamat

Arrastre.

Arquebusier.

ing gold and silver ores by dragging blocks of stone upon a

wooden floor; used in Mexico and s. w. U. S.

"Father of

Arrebo, ANDERS CHRISTENSEN, 1587-1637. Danish poetry." His most noted poem is the Hexaëmeron. Arrenotokia. Form of parthenogenesis, in which males are produced from unfertilized eggs, as in bees.

Arrest. Taking a thing or a person into legal custody. It is applied to the seizure of property in admiraity. The arrest of a person may take place in civil suits, chiefly those for torts, such as assault and battery, or frauds upon creditors; or in a criminal proceeding. Criminal arrests may be made by an officer, or by a private person, and with or without a warrant. In the latter case it must be shown that a felony had been committed; in either, that reasonable grounds existed for suspecting the person arrested.

Arrianus, FLAVIUS, of Nicomedia, ab.100-ab.170. Stoic philosopher, pupil of Epictetus, whose Discourses he reported. He wrote a history of the Expedition of Alexander which is highly valued.

Arriaza, JUAN BAUTISTA, 1770-1837. Spanish poet and official. Emilia, 1803.

Arris. Sharp edge formed by the intersection of two sides of a stone. An arris rail is of triangular section, the two faces being inclined at angles of 45 degrees with the horizontal.

Arrival Curve. Representing graphically the relation of time to the gradual change of effect produced upon a receiving instrument, when any condition or state has been transmitted

from a distance. E.g., the curve may represent the relation of time to the rise of potential in a galvanometer, when the latter is attached at one end of a long conductor, and an electric current is made to flow in at the other.

Arrow-arum. Peltandra Virginica. Plant of the natural family Araceae, native of e. N. America. Arrow Games. The use of the arrow in divination and games is the direct outgrowth of its general use by primitive man, combined with his early appreciation of the importance and relation of the four cardinal points. The origin of many sedentary games may be traced to it. See MEISER GAME, Arrow-grass. Triglochin maritimum. Plant of the Alismaceae, native of the northern hemisphere.

PITCH POT, TAB, PACHESI, and CHESS.

Arrowhead. Sagittaria sagittifolia and other species

Arrowhead (Sagittaria sagittifolia).

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viceable condition. The Arsenals of Construction are Springfield, Mass., Watertown, Mass., Watervliet, N. Y., Frankford, Pa., and Rock Island, Ill. The Storage Arsenals are Allegany, Pa., Augusta, Ga., Benicia, Cal., Columbia, Tenn., Fortress Monroe, Va., Indianapolis, Ind., Kennebec, Me., New York, San Antonio, Tex., St. Louis Powder Depot, Mo., and the U. S. Powder Depot, Dover, N. J. At the headquarters of the various military departments depots are established from which issues proved at the Sandy Hook Proving Ground. All small arms, are made to troops of those departments. All ordnance is swords and sabers are made at the Springfield Armory. The field, siege and sea-coast guns and mortars are made at Watervliet-the plant being capable of producing guns of 16-inch caliber and 120-tons weight. Carriages for seacoast guns, and projectiles, are made at Watertown, as well as all tests of material used in gun construction; 100 seacoast guns and their carriages are now being made by a private company. Small arms ammunition is made at Frankford, and also sights and metallic cases for field guns, and inspecting apparatus. The leather work of army equipments, belts, harness, and carriages for field and siege guns are made at Rock Island.

The arsenals of Europe receive and preserve arms, munitions and equipments that are manufactured either at private or public establishments. Generally they consist of a principal court surrounded by shelter sheds for artillery material, and of buildings containing great halls in which portable fire arms and their accessories are stored; also buildings for the bureaus and personnel of the administration. The workshops for carpentry, wheelwrights, blacksmiths, etc., and repairs in general are arranged in secondary courts, and in isolated positions at safe distances the magazines for powders and explosives are provided.

Arsenals of this kind exist at many fortified places in Europe and at several of the capitals. Among the most important of these are Vincennes, Lille, Berançon. Grenoble, Perpignan and

northern hemisphere.

Arrowroot. Maranta arundinacea. Plant of the natural family Marantaceæ, extensively cultivated in tropical America for its farinaceous rootstocks, from which starch of

Arrowroot (Maranta arundinacea):

A, flowering branch; B, base of flower stem; C, branch of the rhizome. same name is prepared. It is easily digested and free from irritant effects upon the stomach and intestines. Obtained also from other species of Maranta, and from Curcuma angustifolia, Alstroemeria ligtu, and Zamia integrifolia.

Arrowsmith, AARON, 1750-1823. English cartographer. Arrowsmith, JOHN. D.D., 1602-1659. Westminster divine; prof. Cambridge 1644. Tactica Sacra, 1657.

Arrow-wood. Shrubs of the genus Viburnum in N. America; also known as Laurestinus.

Arsacidæ. (1) Dynasty of 27 Parthian kings reigning from 250 B.C. to A.D. 226; named from Arsaces I., founder of the kingdom, originally chief of a nomadic tribe. Famous among them were Mithradates I. and II. (2) Dynasty of Armenian kings who reigned from 149 B.C. to A.D. 428; founded by Artaxias I., who was related to the Parthian line. Tigranes I., 96-55 B.C., raised a petty kingdom to a powerful empire. Arsenals and Armories. The arsenals and armories of the U. S. Army manufacture and supply to the army all the arms, ammunition, accouterments and equipments required for the service, make necessary repairs, and issue the various supplies required to keep the arms and equipments in a ser

England; Berlin, Koenigsberg, Neiss, Dantzic and Spandau in Germany; St. Petersburg, Kief and Moscow in Russia; Vienna, Budweiss and Prague in Austria; Turin, Naples, Ancona and Genoa in Italy; Madrid, Seville, Palma and Barcelona in Spain. Besides these, many European States possess arsenals of construction especially devoted to the artillery service, where the material of artillery is fabricated; such as carriages, etc. The most important of these in France are located at La Fère, Douai, Berançon, Grenoble, Rennes and Toulouse. The British arsenal of Woolwich, founded about 1720, is a vast establishment based on the general principle that provision for the production of every kind of warlike store shall be made there, but only to a degree so limited that there shall remain abundant scope for the encouragement of the same class of manufacture by private establishment. And this principle is largely followed by other nations, whence such great establishments as Krupp's at Essen, Germany, are possible. Woolwich not only contains vast magazines of guns, mortars. shells, powder, and other warlike stores, but workshops and skilled artisans by means of which all such stores for both military and naval service from the simplest implements to the heaviest modern breech-loading cannon can be fabricated, inspected, proved, and stored for issue when emergency arises. The arsenal covers about 60

acres.

Arsenic, As. At. Wt. 75. It was first prepared by the Western alchemists in 13th century. When heated to a red heat it burns with a bluish flame; the vapor has the odor of garlic. It combines with many elements directly. Nitric acid and aqua regia oxidize it to the oxide, As,O,, or arsenic acid, H,ASO,. The element itself is not poisonous. The method most generally used for detecting arsenic or its compounds, is known as Marsh's Test: this consists of getting the substance in solution, and then pouring some of the liquid into a vessel containing pure zinc and pure dilute sulphuric acid. If arsenic be present it will be converted into arsine, the presence of which can be recognized by heating the tube through which the gas is passing, and by holding a piece of porcelain in the flame, when the characteristic arsenic spots" will be formed. It occurs in nature as native arsenic, not very abundant, and in large quantities as the arsenide, or sulpho-arsenide, of other metals. The arsenical pyrites contain iron with arsenic, or sulphur and arsenic, and are the principal ore, the largest deposits being found in the Hartz Mountains, Saxony, Silesia, and Bohemia. Large amounts of arsenic oxide condense in the flues attached to the furnaces of silver, lead and tin works. The pure sulphide of arsenic is found in nature as orpiment and realgar, but not abundantly enough to constitute it a useful ore.

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Metallic arsenic volatilizes just after fusing, and it has therefore to be always obtained by distillation and condensation. The native arsenic, or arsenical pyrites, needs only to be heated in a closed retort to a red-heat, when the arsenic is entirely volatilized. These retorts are fire-clay tubes ab. 6 inches in

diameter by 4 ft. long, placed in two rows in a furnace. The tube projects outside the furnace, where a clay extension is joined to it by means of a sheet-iron pipe. The arsenic condenses inside the iron tube, and is easily scaled off when cold, and sold without further treatment. At Freiberg, 800 lbs, of ore are treated in a furnace in 10 hours, producing 160 lbs. of arsenic. If impure arsenious oxide, as from the dust flues of tin works, is mixed with charcoal dust and treated in the same furnace, the metal distills over in a similar manner. Siemens and Halske have obtained arsenic electrolytically by dissolving native arsenic sulphide in a bath of ammonium, or sodium-sulphide solution, and electrolyzing with insoluble anodes of carbon or platinum and depositing on copper cathodes.

The alchemist Geber speaks of sublimed arsenic (meaning the white oxide) in the 8th century, and Albertus Magnus describes the preparation of metallic arsenic from its oxide in the 13th century.

Arsenic is steel-gray, has metallic luster, is brittle, and volatile at 180° C. without previous fusion. Its vapor is poisonous to inhale. The specific gravity is 5.7, and the specific heat 0.083. The only important use of metallic arsenic is for shot-metal. Lead, with one-half to one per cent of arsenic, produces more regular spheres than pure lead. No other alloys are in practical use, the general effect of arsenic being to make other metals The total world's production of metallic arsenic is probably less than 100 tons a year; its selling price is twenty cents per lb. Arsenic Acid. HASO,; made by oxidizing arsenic trioxide with nitric acid. It is a tribasic acid. Its solution in water has a strongly acid reaction. It is an oxidizing agent, and is used as such in the manufacture of aniline dyes.

brittle.

Arsenical Pyrites. See ARSENOPYRITE. Arsenic Anhydride. See ARSENIC OXIDE. Arsenic Disulphide. As,S,. Occurring in nature as REALGAR (q.v.). It is made artificially by melting together arsenic and sulphur. It is an orange-red powder, sometimes used as a pigment.

of ferric hydroxide and magnesia, which forms with arsenic trioxide an insoluble compound.

Arsenious Sulphide, or ARSENIC TRISULPHIDE. As,S,. Occurs in nature as ORPIMENT (q. v.). It is made by heating sulphur and arsenic together, or by passing hydrogen sulphide into a solution of an arsenic compound, when a yellow precipitate is formed. It dissolves in soluble sulphides.

Arseniuretted Hydrogen, or ARSINE. ASH,. Poisonous, colorless gas, having a disagreeable odor; made by adding a solution of any compound of arsenic to zine and dilute sulphuric acid. It is unstable when heated; when ignited in the air it takes fire, burning with a pale-blue flame, and forming arsenic trioxide.

Arsenoblasts. Supposed "male" portion of cells; sepa rated as spermatozoa in the testes, or as polar globules on the

ovum.

Arsenopyrite. Widely distributed mineral, containing 46 per cent arsenic, 34 iron, and 20 sulphur. It has a metallic luster and a white or grayish color, which sometimes cause it to be mistaken for silver. Its streak-powder is dark grayish black. In hardness it is a little less than quartz. It is frequently found in company with ores of silver, lead, tin, and other metals, and is the principal ore from which arsenic and the numerous arsenical compounds of commerce are obtained. Sometimes it is auriferous and is worked for the gold it contains. It is treated on a large scale in Cornwall and Devon. Considerable quantities are also mined in Silesia, when the mineral is associated with serpentine. It has not been found in paying quantities in the U. S., though it has been worked to a considerable extert in Canada. It is also known as mispickel.

Arsine. See ARSENIURETTED HYDROGEN.

Arsines. Compounds derived from arseniuretted hydrogen (ASH) by the replacement of the hydrogen by organic radicals; as methyl arsine, ASH,CH3.

Arsenic Sulphide, or ARSENIC PENTASULPHIDE. As,S. It separates as a bright, yellow powder from the solution of sodium sulpharsenate, Na,ASS,, upon the addition of acids. Arsenious Oxide, ARSENIC TRIOXIDE, or WHITE ARSENIC. As2O3. Occurs in small quantities in nature. It is manufactured in large quantities by roasting arsenical pyrites, FeAsS. It is soluble with difficulty in water, easily in hydrochloric acid. It is a colorless, amorphous, vitreous mass, which becomes opaque and crystalline in time; or it is a white powder. It has a weak sweet taste, and is very A senious Oxide Muffle. poisonous; a dose of 2 to 3 grains is generally sufficient to cause death. It is used extensively in medicine for strengthening the respiratory organs

Arsenious Oxide Condensing Chambers.

Arson. At common law, the willful and malicious burning of another's house, formerly punishable with death. The offense has been extended by modern statutes to the fraudulent burning of one's own house, and has been divided into degrees, with varying punishments.

Art, ORIGIN OF. The earliest art of design was probably developed from the wish (1) to gain such power over animals, in the quest for game, as was supposed to be derived from the possession of drawings or carved figures of them; (2) to obtain similar power over other human beings, and (3) to bring the ancestral spirit or deity into immediate relations with the suppliant for favor, by providing him with an adjacent image as residence. The earliest known works of design are the spirited drawings on ivory and bone of Palæolithic man. To these drawings such magic purpose has been recently ascribed by Lazar Popoff. The same superstition is supposed to have been attached to surface drawing, which, with many savages, relates to the shadow, and identifies it with its original. Many modern primitive cultures have attached such magic power to the picture and the image. Although Egyptian art had attained remarkable perfection at the earliest dates known to us, it was then applied to magical uses. All the early Egyptian paintings of natural scenes and daily life known were tomb paintings, intended to assist the life of the deceased in the spirit world by magical projection. The early Egyptian statues were all simulacra of the dead person placed in the tomb as abidingplace for the spirit, or statues of deities, which again were magically endowed with the life and power of the god. From our knowledge of modern savages, of the oldest known art of a civilized people, the Egyptians, and of the art of Palæolithic man, the conclusion may be drawn that the original use of art was not at all the imitation or copy of living nature as we understand it. Writing has also magical power in the conceptions of primitive peoples. The earliest writing was picture writing, and doubtless the picture was employed for writing at a very early stage of primitive culture; but here again the magic quality was assumed to coexist, and continues to subsist in the conventional derivative hieroglyphic or alphabet characters. It has been proven that, in many or most cases, the patterns of primitive man go back to repeated pictures or carvings of sonie one design made under the same superstitions. E.g., the entire system of pattern ornament in the Hervey Islands in the Pacific has been traced to carvings of ancestral spirits in guise of the human figure. The entire sys

evolution from the talismanic repetitions of the Lotus symbol of Egypt. Artabanus. (1) Brother of Darius, and counselor of his nephew Xerxes. (2) Commander of the body-guard, who assassinated Xerxes, 465 B.C. (3) 4 Kings of Parthia bet. 216 B.C.

A.D. 226.

Artabazus. (1) Persian general of Xerxes. He escaped after the battle of Platæa 479 B.C. with 40,000 men. (2) Satrap of Bactria ab. 330 B.C.

Artaphernes. Persian general of Darius, defeated at Marathon 490 B.C., and of Xerxes in the invasion of Greece, 480 B.C.

Artaud, NICOLAS LOUIS, 1794-1861. French tr. of Sophocles, Aristophanes, and Euripides, 1727-30-32.

Artaxerxes I., LARGIMANUS. King of Persia 465-25 B.C. The Egyptians revolted ab. 460, and were re-subjected ab. 455. -A. II., MNEMON, eldest son of Darius II., king of Persia 405– 362 B.C. He defeated the army of his brother, CYRUS, at Cunaxa 401.-His son, A. III., reigned 361-38 B.C., subjugated Egypt ab. 350.

Artedi, PETAR, 1705-1735. Swedish icthyologist. Artemia. Salt water form of Branchipus. Artemidorus, DALDIANUS. Greek writer of 2d cent. work on the interpretation of dreams exists.

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Artemidorus, OF EPHESUS, ab. 100 B.C. Geographer. Artemis. Daughter of Zeus and Leto; twin-sister of Apollo; called Diana by the Romans; huntress, sometimes sending plagues and death among me.., sometimes relieving their sufferings; a maiden-divinity, unconquered by love; identified with the moon, as Apollo with the sun. She had a famous temple at Ephesus.

Artemisia. (1) Queen of Halicarnassus, who led her troops under Xerxes at Salamis, 480 B.C. (2) Sister, wife and successor of Mausolus, prince of Caria, 352-50 B.C. After his death she mixed ashes in her drinks, and built the mausoleum to perpetuate his memory.

Artemisia. See WORMWOOD.

Artemisium. Promontory at n. end of Euboea, scene of a 3 days' naval battle between Xerxes and the Greeks 480 B.C. Arterial Pressure. Pressure of the blood in the arteries, which normally should maintain a column of mercury ab. twenty inches high.

Arteries. Tubes which take the oxygenated blood from the heart and distribute it through the body, connecting with the veins by microscopic vessels called capillaries. The largest and most important is the aorta, which springs from the left ventricle of the heart, divides into two common iliac arteries, each of which divides to form the internal and external iliacs, the former of which yields the vesical, uterine, vaginal and hæmorrhoidal arteries. The external iliac passes out of the pelvis, and supplies the thigh, leg, and foot. From the portion of the aorta within the abdomen are given off the inferior and superior mesenteric to the intestines, the renals to the kidneys, in males a branch to the testicle, and in females to the ovary; and the cœliac, which supplies the stomach, liver and spleen. From the arch of the aorta spring on the right side the short innominate artery, which divides into the subclavian and common carotid, which on the left side arise independently from the aorta. The latter ascends in the neck and supplies the brain, eye, and a portion of the nose and skin of the forehead. The external carotid is distributed to the neck, face, tongue, teeth, larynx, pharynx, ear, and most of the superficial parts of the head. The subclavian supplies the fore part of the chest. After reaching the armpit, the clavicular supplies the shoulder, arm and fingers.

The diseases of the arteries are arteritis, atheroma, aneurism, and the degenerations which occur in other portions of the body. They are made up of three coats, an outer, middle, and interior, the latter being sometimes divided into two. Of these coats the middle is the most important, being highly elastic, and serving to maintain the tubular shape of the vessel; when tied tightly it retracts, so that the caliber of the artery is lessened and hæmorrhage more easily controlled. Hæmorrhage from arteries is always serious when the vessel is of any size, and is distinguished by the fact that the blood is thrown out in jets and is of a bright scarlet color; it can be controlled only by tying a thread or cord around them, or by exercising pressure upon the side nearest the heart, i.e., on the body side of a limb.

Arteritis. Inflammation, which may be purulent, of the coats of an artery, due to injury or to obstruction of the flow of blood through it, which may result in its becoming distorted out of shape, its obliteration or atheroma.

ular leader. He supported England against France and the Artevelde, JACOB VAN, 1285–1345. Brewer of Ghent; popCounts of Flanders; was killed in insurrection, in consequence of his proposal that the son of Edward III. of England should be elected Count of Flanders.-His son PHILIP, 1340-1382, led in the war with Bruges, and was regent of Ghent for a few months, till defeated and slain at Rosbeke.

Arthritis. Inflammation of the structures of a joint: comonly the result of an injury, or one of the accompaniments treated by rest, hot and cold applications, and the remedies of a disease, such as gout, rheumatism, gonorrhoea, etc.; best appropriate for the diseases which it accompanies.

Arthrobranchia. Gills borne on the bases of the legs in lobster-like animals.

Arthrogastra. Group of Arachnids, including Phalangida, Pseudoscorpionida, Scorpionida, Pedipalpi, and Galeodea.

Arthrology. Branch of anatomy which treats of the joints, articulations, and ligaments.

Arthropoda. Articulated, bilaterally symmetrical, animals with heteronomous segments and with jointed appendages. They have a supra-oesophageal ganglion and a ventral nerve-chain; e.g., Lobsters, Spiders, and Insects. The groups included are Crustacea, Arachnida, Onychophora, Myriapoda, and Hexapoda (Insecta). The first two are the Acerata, the others Cerata. The antennæ of Crustacea, etc., are not homologous with those of an insect.

Arthropomata. See TESTICARDINES.

Arthrospore. Spore produced from a bacterium by a metamorphosis of an entire joint or cell, as in the vegetative stage. See SPORES OF BACTERIA.-In botany, bacteria or schizomycetes which do not form internal spores.

Arthrosterigma. Jointed filament of cells in certain

lichens.

Arthrostraca, HEDRIOPHTHALMATA, or EDRIOPHTHALMATA. Malacostracous Crustacea with lateral, unstalked eyes, seven or fewer separate thoracic segments, but no fold of the skin forming a carapace. The sub-orders included are Amphipoda and Isopoda.

Arthrozoa. Group of animals including Arthropods, Sagitta, and Nematoscolices.

Arthur, ab. 550. Mythical king of the Silures, said to have defeated the Saxons in several battles, and been mortally Modred; hero of the Round Table and of numerous mediæval wounded at Camlan, when fighting against his revolted nephew legends.

Arthur, CHESTER ALAN, 1830-1886. Twenty-first pres. U. S.: collector of N. Y. 1871-78; elected vice-pres. 1880; succeeded to the presidency on Garfield's assassination Sept. 1881. Arthur, JOSEPH CHARLES, b. 1850. American mycologist; editor of the Botanical Gazette. Author of numerous papers on Fungi.

Arthur, TIMOTHY SHAY, 1809-1885. American author of many once popular tales, and founder in 1852 of Arthur's Home Magazine.

Arthur, WILLIAM, b. 1819. Irish Wesleyan divine. His Successful Merchant, 1852, and Tongue of Fire, 1856, were very

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Articles of Religion. Name appropriate to all confessions of faith, but applied especially to the 39 Articles of the Ch. of England. Cranmer, Ridley, Latimer and others drew up 42 Articles, which were pub. 1553, and enforced till Mary's accession. Under Elizabeth, 1563, they were revised and reduced to their present shape. They were obligatory at Oxford and Cambridge till 1871. The American P. E. Ch. accepted them, but in 1892 made them an appendix to the Prayer Book.

Articles of War. By the provisions of Section 1342, Revised Statutes, the armies of the U. S. are governed by 128 rules, which every officer must subscribe and every enlisted man swear obedience to, on entrance into the military service. Articulata. See TESTICARDINES, CRINOIDS, and CYCLOSTOMATA (MOLLUSCOIDEA).

Articulates. All jointed invertebrates, now included in the Arthropoda and Annelida.

Artifact. Organic structure, the result of artificial pro

cesses.

Artificial Draft FOR STEAM BOILER FURNACES. Plan by which the air to support combustion of fuel on boiler grates shall be brought in by some engineering device instead of by the natural draft caused by a warm chimney. Air may be forced into the furnace by a fan, blower, or steam jet, or it may be exhausted by one of the same means at the back or chimney end of the setting. The pressure system has some decided advantages. These methods make the steam user less dependent on atmospheric variations, on size, height, and therefore cost, of chimney stack; the evaporative capacity of the boiler of a given size can be increased, and a kind and size of fuel can be used which it would be difficult to use with chimney draft only. Ab. 250 cubic ft. of air should be supplied per lb. of coal.

Artificial Horizon. Free reflecting surface of a liquid (usually mercury, on account of its high reflecting power) employed for obtaining the altitude of some distant body when the true horizon is not visible. This altitude is half the angular distance between the object and its image reflected in the surface. The angles may be measured with a sextant or theo

dolite.

Artificial Indigo. Indigo blue or indigoline, prepared from artificial source, usually by the reduction of the orthonitrophenylpropiolic acid. The latter chemical is so expensive that artificial indigo cannot yet compete with the natural product in dyeing, though it finds a limited application in calico printing.

Artificial Limbs. Have undoubtedly been used for many centuries, Herodotus mentioning them; but not until within recent times did they consist of anything but rude affairs of wood or metal. Cork was at one time used to some extent, but at present they are almost exclusively made of papier maché supported by metal, those of American make being by far the best. Their efficiency varies with the length of the stump to which they are attached by means of straps and bands. By the use of springs and pneumatic apparatus hands have been constructed, the fingers of which are made to contract at the will of the wearer, who often becomes very expert in performing the ordinary duties of the hand.

Artificial Stone. Made of sand, cement, and sometimes certain chemicals: Ransome's is made of sand, gravel, silicate

of soda, chloride of calcium and water; the chemicals forming silicate of lime, which binds together the grains of sand and gravel. Frear's stone is made of sand, hydraulic cement, gum shellac, and water. The only kinds that have been extensively used are beton and concrete, in which hydraulic cement is the binding material.

Artificial Wants. Desires for such gratifications of the senses as have become habitual, but are not necessary to the preservation of life, e.g., for food of delicate taste, for pleasant odors, for music, and for intellectual stimulus.

Artillery. The projectile machines of the ancients, as catapultæ, ballista, etc., for throwing heavy stones, shafts, bolts, and other missiles, had reached great perfection before gunpowder was used in cannon. This discovery, attributed to Schwartz in 1320, marks the epoch separating ancient from modern artillery. Missiles were first projected by gunpowder from cannon at the siege of Quesnoy, France, 1340; from that time on, the development of artillery was progressive. From the 14th to the 17th century the tendency was toward the making of great guns; e.g., that used by Mahomet II. at the siege of Constantinople in 1453, which weighed 18 tons, caliber 25 inches, and the wrought-iron "Mons Meg," firing a granite projectile of 330 lbs., used in the siege of Dumbarton Castle 1489, and last fired 1683. During the 17th and 18th centuries, more attention being paid to ease of handling, accuracy and range, the size of guns and projectiles was correspondingly diminished. Starting with these monster guns of the 15th century, cannon were first made of wrought-iron staves hooped with iron rings; but, as the art of casting developed, bronze and cast-iron guns began to appear ab. 1550, and held their ground for near 300 years; then, owing to improved powders and the increasing demand for greater range and accuracy, cast-iron guns, rifled, and hooped with wrought-iron or steel, came into use 1856-1880; finally all new guns since 1880 have been made of steel.

The development in artillery construction which the finished coast-defense gun of to-day exhibits, in comparison with its original type, is due to many mutually assisting causes. The most important of these are, the establishment of artillery schools, where the principles of the art could be formulated and scientifically studied; the necessity arising for better mounting and pointing, and quicker manipulation; the invenother more perfect ballistic machines, whereby the initial tion by Robins of the ballistic pendulum, leading afterward to velocities of shot and characteristics of gunpowders could be ascertained and bettered; the invention of scientific apparatus for the inspection and proof of guns; the improvenients and development of slow-burning powders and of high explosives, from which have resulted the determination of safe strains in gun construction; the improvements in the methods of igniting the charge with greater certainty and celerity; the establishment and arrangement of sights for cannon; and the chambering, rifling and breech mechanism.

The early cannon were nothing more than metal tubes closed at one end; the modern sea-coast gun is built up from a central steel tube, over which successive steel jackets are shrunk so as to bring a previously computed initial pressure on each one within. In this way the gun is enabled to withstand the enormous energy of each discharge and perform the function required of it. The sea-coast guns in the U. S. Service are the 8, 10, 12 and 16-inch B. L. (breech-loading) Rifles, whose weights are 14, 30, 50, and 100 tons, and the 12-inch B. L. Mortar. The immediate supporting carriage for a coast defense gun is designed to combine facility in maneuvering with extreme accuracy in pointing, and, in addition, to protect it from the enemy's fire. The latter desideratum is effected by the use of the hydraulic gun-lift, or the Gordon, Crozier, or other disappearing gun-carriage.

tillery, the resulting armament in the U. S. Service being Corresponding improvements have taken place in siege arthe 5-inch B. L. Steel Rifle, the 7-inch B. L. Howitzer, and the 7-inch B. L. Mortar.

The efficiency of field artillery depends on the accuracy, power and rapidity of its fire, on the destructive capacity of its projectiles, and on the mobility of its equipment. The field artillery has kept pace in the march of improvement with the great guns. The field batteries of four or six guns can now move with infantry, and the horse batteries can keep up with cavalry. The guns used in the U. S. Service for field artillery are the 3.2 and the 3.6-inch B. L. Rifles and the 3.6-inch Mortars.

Artillery Plants. Herbs of the geuns Pilea, natural family Urticaceae, natives of tropical regions.

Artillery Position. Location and arrangement by which artillery can be most effectively employed. This depends on its character, caliber and range. Field guns, being mobile, are grouped in one or more batteries and form part of the fighting strength of an army. Their location in battle depends on the