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writings, mostly philosophical, and of less interest, are still extant, besides the Defence' already mentioned. The latest and best edition is J. van de Vliet's Melamorphoseon (1897) and Apologia and Florida "(1900). English translations are: The Golden Ass, by Sir G. Head (1851), and by Adlington (1506; new ed. 1892); and Eros and Psyche by R. Bridges (1885). See also "J. G. Frazer's Golden Bough.

Apulia (Ital. Puglia), a territorial div. (compartimento) of S. Italy: stretches along the Adriatic from the river Fortore (w. of the lofty Gargano promontory) to the extreme S.e. corner of the peninsula, C. Santa Maria di Leuca, and thus embraces the three provinces of Foggia, Ban, and Lecce. Its total area is 7,380 sq. m., and its pop. (1901) 1,949,423. Apart from Monte Gargano (5,120 ft.), the N. part of the territory is a level plain—a rich grazing ground in winter, when it supports thousands of sheep, but in summer it is parched and dry. The s. part, between the Gulf of Taranto and the Adriatic, is in part a low, dry limestone plateau, but yields excellent wheat, which is used in the manufacture of macaroni, also barley, maize, beans, lentils, pease, and good olive oil. Wine is generally produced; other products are fruits (figs, oranges, lemons, olives, etc.) and salt, besides a little cotton, flax, tobacco, and silk. Marble is quarried on Monte Gargano. The people live, for the most part, in large towns, which are, as a rule, situated either on the Adriatic coast or on the edge of the limestone plateau. Among the former are Barletta, Bari, Monopoli, and Brindisi; among the latter, Andria, Bitonto, Putignano, Lecce. The chief ports on the Gulf of Taranto are Taranto and Gallipoli. The summers are hot, and malaria clings to certain swampy tracts along the coasts. For centuries this part of Italy was dominated by Greek civilization, disseminated from the cities of Magna Graxria; but, opposing Rome, it suffered severely in the social war of 90-88 B.c.. and again after the failure of Hannibal's designs, which it had supported. After Rome's supremacy crumbled to pieces, the region was divided between the Eastern empire and the duchy of Benevento. During the llth and 12th centuries it was overrun and subjugated by the Normans, and so passed under the crown of the Two Sicilies. See Gregorovius's Apulische Landscha/ten (4th ed. 1897). See also Italy; and for history, Naplks.

Apure, riv. in Venezuela. See Orinoco.

Apurlmac. (1.) River, S. America, rue6 about 15° 5. m the Vol. I.—20


Peruvian Andes, and is a head stream of the Amazon. After its union with the Pirene, it flows, under the name of Tambo, and after a course of 500 m. it joins the Ucayali. (2.) Department, Peru, S. America. Area, 8,187 sq. in.; pop. (1896) 177,387. Its cap. is Abancay (pop. 3,000).

Aqua fortls. See Nitric Acid.

Aquamarine, a name given to the transparent bluish-green or sea-green varieties of beryl. As compared with the pure green beryl or emerald, it is of little value; it is, however, used to some extent as a semi-precious stone. It is found in many places, but comes chiefly from Brazil and the Urals. Some specimens weigh as much as 15 Ibs. Fine aquamarine has been found at Stoneham and at other localities in Maine. See G. F. Kunz, Gems and Precious Stones of North America, and O. C. Farrington, Gems and Gem Minerals.

Aqua regla (Lat. 'royal water,' because it dissolves gold), a mixture of nitric acid with from two to four times as much hydrochloric acid, which sets free chlorine; to this its solvent action is clue.

Aquarium, tank or vessel, or a collection of these, containing aquatic plants and animals, living as nearly as possible under natural conditions. The basis of the modern aquarium is the mutual dependence of animals and plants, plants absorbing the carbon dioxide generated by animals, and liberating the oxygen necessary for their respiration. Plants, also, are able to utilize the waste materials of animals. Except on a small scale, however, the condition of balance is difficult to preserve; and almost all recent aquaria, especially those for public exhibition where a considerable depth and bulk of water is to be maintained, have mechanical arrangements for aerating or renewing the water.

The relative simplicity of the fresh-water aquarium is largely due to the fact that many freshwater plants are easy to obtain, and grow readily, especially if planted in submerged flower-pots. The Canadian water-weed (Anacharis) will grow and flourish without soil. Various species of duckweed (Letnna) can similarly obtain all the food they require from water; but as their fronds float at the surface, their aerating value is slight. Bladderworts Cutricularia), floating or partially submerged, are interesting, with thread-like leaves and many larva-trapping bladders. Pondweeds (Potamogeton), with floating or submerged leaves; the water-nut (Trapa)- the fanwort (Cabomba) with dissected, fan« like submerged leaves; the hornwort (Ceratophyllu w), spreading


finely forked foliage under the water; and the common tapegrass (Vallisneria) which sends fong leaves to the surf ace; the common water buttercup (Ranunculus delphinifolius) and water starwort (CoJlilncne vcrna) all grow well in aquaria and assist in aerating the water. Of the animai inhabitants, by far the easiest to keep alive are those capable of breathing both air and water, such as the aquatic amphibians, especially newts, axolotls and larval forms, molluscs such as the water snails, and larvx of aquatic insects. A glass aquarium should always contain a few water-snails (Limnea, Planorbis, Physa), since these will eat the minute vegetation (Con/ervtf) which tends to grow everywhere, and so keep the glass clean and clear. Fish require care; the beginner is most likely to be successful with sticklebacks and minnows. If the water becomes contaminated with surplus food, the fish are liable to attacks of 'fungus' (Saprolegnia). If noticed in time, this may be cured by transferring the affected forms to running water; but if the disease once obtains a hold, there is no cure except the removal of all the inhabitants, and the thorough disinfection of the aquarium.

The salt-water aquarium presents more difficulties than the fresh, as it is not easy to repair damage wrought by inattention or accident, and an unnoticed death may poison all the other inhabitants. Nor are seaweeds so easy to grow as fresh-water plants. Sea lettuce (Ulva) is as good a plant as any, and should t>e obtained attached to a stone or piece of rock. Of animals, the beautiful sea-anemones, many of which are hardy in captivity; the echinoderms—star-fishes, sea urchins, brittle stars, etc.; marine worms, such as Sabella, Scrpula, and others; and certain marine molluscs and crustaceans, are well worth cultivation. Extensive experimental marine aquaria are attached to the biological stations of Naples and elsewhere in Europe, and at Wood's Holl, Cold Spring Harbor and elsewhere in the United States. Other notabl; aquaria exist at Brighton (England), Berlin and Hamburg (Germany), and in New York and Washington. That in the old Fort Clinton (Castle Garden)on the Battery in New York, managed since 1903 by the N. Y. Zoological Society, is one of the largest and finest in the world. See Taylor's Aquarium (1881); Smith's The Aquarium (1900).

Aquarius, a southern zodiacal constellation, and the eleventh sign of the zodiac, symbolized Aquatic A ii I nulls Aquatint


coincident asterism only on February 14. None of its stars are of the third magnitude, but it includes the fine binary ( Aquarii, to which Dobcrck has assigned a period of 1,625 years, a magnificent globular cluster (Messier 2), and the 'Saturn' nebula (N.G.C. 7009), a pale-blue planetary with ring-like appendages.

Aquatic Animals. It has become almost an axiom of modern science that life originated in the water, and numbers of animals, especially the simpler forms, still inhabit that medium. This is true of the vast majority of the Protozoa, sponges, Cvcfentcrata and echinodcrms. It is the rule for unsegmented worms, except where these are parasitic; and, among annelids, the earthworms and land-leeches are obviously forms which have later acquired a terrestrial habit. Though, among arthropods, the great groups of insects, myriapods, and arachnoids are typically terrestrial, yet the Crustacea are almost all aquatic. Among molluscs, only the gasteropod class includes land forms.

In vertebrates, the line which separates the typically aquatic and typically terrestrial forms passes througn amphibians, which may, as in the frog, be water animals in youth and land animals in adult life. Nevertheless, the crocodiles, turtles, and water snakes among reptiles, many birds, the sirenians, cetaceans, and seals among mammals, illustrate the fact that members of typically terrestrial groups may return to a purely aquatic life. An important point in these cases is that the aquatic reptile, bird, or mammal retains its terrestrial habit of breathing air by lungs, and shows no tendency to reacquire gills. In general we may say that in the above amphibians the aquatic habit, when present in a vertebrate, has been secondarily acquired by a return from an earlier terrestrial habit. The adaptations to the aquatic life are therefore usually more easily studied in such vertebrates than in invertebrates, where the aquatic habit is often the primary one. The whale, for example, as contrasted with an ordinary terrestrial mammal, shows some very striking modifications of structure. The spindle-shaped form repeated in fish, is less an adaptation to the aquatic life in itself than to swift movement in water. To a similar cause the absence of the hair and of the hind limbs is to be assigned. The use of the tail as the main organ of propulsion is common among aquatic animals; while the fact that the bodv lose-; in water a large proiwrtion of its weight sets the limbs free from the sup


porting function which they must perform in land animals and enables this animal to acquire its huge size.

A very common structure in those aquatic animals which are capable of rising and sinking in the water is some form of hydrostatic organ, or internal reservoir of gas. All air-breathing vertebrates have these in their lungs, which were perhaps themselves in origin merely hydrostatic organs; fish have usually a swim-bladder; many cuttles have air-spaces in their 'bone' or float; the pearly nautilus has its chambered shell filled with gas; even many of the Protozoa have bubbles of air in their soft bodies. While many aquatic animals are swift swimmers, and others creep passively at the bottom, the fact that large bodies of water are themselves always in motion renders life in water possible for two sets of animals to whom terrestrial life would be impossible. There are, first, the drifters or 'plankton,' animals which can make no headway against currents, but float idly with them. This fauna consists largely, though not exclusively, of the simpler forms of animal life. Secondly, those able to swim actively are designated collectively as nekton.' Finally a large class of forms are fixed to the ground or to other animals, and depend upon the currents in the water to bring food; but in these the eggs or larval forms are usually able to drift or swim in their earlier 1'f-1.

Though aquatic life is most abundant in warm waters, and near shore, it exists in all climates and at all depths; yet there are few forms which are able to range widely, especially in a vertical direction.

Aquatic Plants, or HydroPhytes, are wholly or partially submerged, but do not include

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pond weed (Aponogeton) and Canadian pondweed (hlodea) are other examples; but there are many more. The majority of water plants are fixed in the soil, but some, like duckweed (Lcnuiti) and water soldier (Slratiotcs), float, or at least are free from the soil. The whole surface of a water plant in contact with the water absorbs liquid and gaseous food, and, in the case of flowering plants, such absorptive surfaces are almost or entirely devoid of the stomata and cuticle which arc commonly found in the epidermal surfaces of land plants; but both stomata and cuticle occur on the



upper surfaces of floating leaves. The vascular and fibrous tissues of the stems and leaves an. poorly developed, since they are scarcely required, and the roots are reduced. Large air-spaces occur in the cellular tissue of most water plants, and these become filled with oxygen, for the better respiration of the plant. Most aquatic plants expose their flowers above the surface, and thus are subject to the same means of pollination as land plants. A few only have entirely submerged flowers, as in sea wrack (Zoslera), which, like very few other plants, is submerged in sea water. Most aquatic plants are perennial. Some—e.g. Utricularia (see BladDERWORT)—form dense terminal winter buds in autumn: these drop off, rest at the bottom during the winter, and then develop during the following spring. Others percnnate by means of fleshy rhizomes, which store up food.

Aquatint, an etching process on copper by which prints arc produced imitating the broad effects of India ink and sepia drawings. In this process, areas, not lines, are bitten in by dilute acid on a copper plate, covered with black resin, on which the design has already been traced. Devised by Abbi St. Non in the 18th century, and perfected by Jean Baptiste le Prince (1733-81), the process has now fallen into disuse, except for


the tints printed in some colored pictures.

Aqueduct, an artificial channel for conveying water. The term is now generally restricted to large masonry conduits in which the water flows with a free surface. It is not applicable to pipes working under pressure, as the pipe lines througn which petroleum is forced, but refers specially to a channel raised above the level of the ground as a bridge to span some hollow. The piers and arches of an aqueduct may be of stone, brick, or concrete. The water channel, if of masonry, must be made watertight. An iron or steel water channel or conduit is often used, and as such pipes are now made of large size and of sufficient strength, they are frequently and preferably employed. In the United States many of the aqueducts carrying irrigation water across valleys are timber structures; trestle bridges are largely used, and the timber channels are called flumes, while wooden pipe of cylindrical section, built up of staves held together by iron bands, is also employed. The Romans made littfc use of pipes under pressure; thev raised tne channel on arches to keep it at the proper gradient. Where the height was great, they built two or three tiers of arches one above another; and to make the channel impervious to water, the masonry was coated with stucco. Hewn masonry was generally used, but the Tcpula aqueduct at Rome was largely constructed of concrete. Some of these early aqueducts are still in a good state of repair, and continue to carry water; a good example is that at Segovia in Spain, built about lOfl A.D.

Before the end of the 1st century A.D. Rome was supplied by nine aqueducts, with a total length of over 270 m., of which about 35 m. was raised above ground on arches. The last of these to be built, the Anio Novus, at one point is 109 ft. above ground-level. It is built above the Aqua Claudia, the two waters flowing in separate conduits on the same arches. The aqueduct Ponle delle Torri, at Spoleto, dates from the 7th or Sth century, and is about 300 ft. high, with two series of pointed arches. In the Roman provinces there were the incomparable aqueducts at Nlmcs, at Segovia and Tarragona, at Metz and Mainz, at Antiocht and at Pyrgos, near Constantinople. The ancient Greek world possessed famous aqueducts at Athens (made r. 560 B.C.), at Samos (c. 625), and at Syracuse (still in use). In France, the aqueduct of Maintenon was constructed in Louis xiv.'s time, to bring water to Versailles; it is 4,400 ft. long, over 200 ft. high,


and has three tiers of arches of about 50 ft. span. The first aqueducts of importance in Great Britain were built towards the end of the 18th century to carry canals. They were of masonry, with the bottom and sides of the canal puddled. In the United States the earliest and most important aqueduct was the Croton aqueduct (completed 1842) to carry water to New York from Croton river, a distance of 38.1 miles. It was constructed of masonry with brick lining, and was 8.64 ft. in height and a cross section 53.34 sq. ft. in area. The Croton aqueduct was followed in 1848 by one for Boston, and this in turn by others for the leading American cities as their systems of water-works developed. In 1890 the new Croton aqueduct was completed, and differed from its predecessor in being nearly all in tunnel. This aqueduct is 30.87 miles in length and is of horseshoe-shaped cross section 13.53 ft. in Height and 13.6 ft. in width. Its capacity is 302,500,000 gallons per day, as compared with about 72,000,000 gallons for the old Croton aqueuct. Another recent example of aqueduct construction in the United States is the Wachusett aqueduct, which affords an additional water supply for Boston and vicinity, and whose size and capacity are slightly less than that of the new Croton aqueduct. There were under construction in 1909 an immense new water-supply aqueduct for New York City, to be called the Catskill, and a very long water-supply aqueduct for Los Angeles, Cal.

Few aqueducts (in the sense of bridges) of any length have been made in recent years, as an inverted siphon of pipes serves the purpose, and is much less costly. This feature is a marked point of contrast between the old and new Croton aqueducts in New York. In the first the Harlem River was crossed on the massive granite masonry arched High Bridge, shown in the illustration, while the new aqueduct passes underneath the river, though this section is lined with cast iron. Where the valley crossing is short, however, bridge aqueducts arc found. These are gent-rally built of masonry, with a water channel of concrete, iron, or steel, and examples of these are to be seen on all the large water-works of the present day. A notable example of such construction is the Cabin John Bridge of the Washington, D. C., aqueduct, a masonry structure which for many years possessed the distinction o'f being the largest single stone arch bridge in the world. In the aqueduct supplying the city of Boston there is a granite

MODERN AQUEDUCTs. 1. Cabin John Bridge (Washington, D. C., water Works). 2. oil, Bridge, old Croton Aqueduct, New York City. S. Aqueduct over Masonry and steel

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Aqueous Humor

bridge structure with seven arches, which crosses the Assabet River. See further under Water; also Herschel's trans, of Frontinus's books about Water Supply of Rome (1899); Turneaure and Russell's Public Water Supplies (1901).

Aqueous Humor. See Eye.

Aqueous Bocks, the name given to those rocks that have been laid down beneath water, whether in the form of sedimentary deposits, of accumulations of shells and other animal or plant remains, or of chemical precipitates. See Sedimentary Rocks.

Aqulla, an ancient constellation placi'd S.E. of Lyra, and traversed by the Milky Way. Nova Aquilse, photographically discovered by


Aqulla, Ponticus, a native of Sinope in Pontus, flourished about 130 A.d. He made a translation of the Old Testament into Greek, of which a few fragments survive in Origen's Hexapla. He is said to have been successively a pagan, a Christian, and a circumcised Jew.

Aqulla deell Abruzzl. II.) Province, Italy, in territorial div. Abruzzi and Molise, between the two main chains of the Central Apennines. Cereals, flax, hemp, and fruits are the chief productions. Area, 2,485 sq. m. Pop. (1901) 397,645. (2.) Chief tn. of above; episc. see, and summer resort: stands on a plateau at the foot of the Gran Sasso d'ltalia, the culminating knot of the Central Apennines, 55 m. N.E. of Rome


mercial centre, having access to the sea by means of a lagoon now silted up. It was founded in 182 B.C., was strongly fortified by Marcus Aurelius, and in the 4th century A.d. was the fourth city in point of size and population in all Italy; but in 452 it was captured by Attila, who razed it to the ground, the inhabitants escaping to the lagoons in which Venice was afterward built. In the 6th century (the town having been rebuilt by the Ostrogoths) it became the seat of a patriarch of the church, who wielcTed great political power; but the dignity was suppressed in 1750. Aquileia still possesses an llth century cathedral, and has a museum full of valuable Romau antiquities. Pop. (1900) 2,319.

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Mrs. Fleming in April, 1899, was then of seventh magnitude. Its bright-line stellar spectrum became nebular as it faded. One of the best known short-period variables is 11 Aquilae, which fluctuates from 3.5 to 4.7 magnitude in 7 days 4 hours, and was found by Belopolsky in 1895 to be a spectroscopic binary.

Aqulla, Caspar (1488-1560), the Latin name of a German theologian, Adler, who, after suffering imprisonment in 1519-20 for his advocacy of the reformed doctrines, became professor of Hebrew at Wittenberg (1524), and aided Luther in translating the Old Testament. Becoming Protestant pastor of Saalfeld (1527), he was outlawed by Charles y. (1548), but was restored to his pastorate in 1552.

(135 m. by rail via Terni). The cathedral, first built in the 13th century, has been more than once injured by earthquakes, and has been recently restored. Saffron is extensively grown in the vicinity. Lace-making gives employment to many of the women. Aquila was founded by the Emperor Frederick ii. in 1240, on the ruins of the ancient Amiternum. Pop. (1901) 21,261.

Aqullegla. See Columbine.

Aquileia, or Aglar, vil., Austria, in Gbrz and Gradisca, at the head of the Adriatic, 26 m. by rail N.w. of Trieste. It was in ancient times strongly fortified, and, owing to its position at the foot of several Alpine passes, and on the Via Emilia, was the principal bulwark on the N.E. frontier of Italy. It was an important com

Aqulnas, Thomas, 'the angelic doctor,' was the son of the Count of Aquino, near which town, situated between Rome and Naples, he was born about 1226. Having received the elements of his education in the monastery of Monte Cassino, he proceeded to the University of Naples, and in his seventeenth year joined theDominicans. He afterward studied under the celebrated Albertus Magnus at Cologne; accompanied his master in a three years sojourn at Paris (where he graduated bachelor of theology); then returned with Albert to the school of Cologne as second teacher and magistcr studentium. The University of Paris having assumed a bitter hostility to the mendicant orders, Thomas sprang to the defence of the latter with tongue and pen; and having

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