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to genera found nowhere else, Gulick established the fact that in each mountain valley of the forest region of Oahu there is a great number of local species (200, represented by 700 or 800 varieties) belonging to several genera, and that each of the twenty valleys contains one or more local varieties or, species restricted to that valley. On tracing this wonderfully differentiated assembly from valley to valley, it became apparent that a slight variation in the occupants of a valley as compared with those of the adjacent valley becomes more pronounced in the next or third valley, still more in the fourth, and so on. Thus he was able roughly to estimate the amount of divergence between the occupants of any two given valleys by measuring the number of miles between them (Romanes). Gulick thinks the evolution of these different forms cannot be attributed to differences in their external conditions. The forest area, covering one of the mountain ranges, in which the snails live, is about 40 miles long and 5 or 6 miles wide. He states that the rainfall on the northeast side of the mountain is somewhat heavier than on the opposite side, and the higher ridges of the mountains are cooler than the valleys; but the valleys on one side of the range have a climate the same in every respect. The vegetation in the valleys differs somewhat from that on the ridges; but the vegetation of the different valleys is much the same; the birds, insects, and larger animals are the same. Though, as far as we can observe, the conditions are the same in the valleys on one side of the range, each has a molluscan fauna differing in some degree from that of any other. He also adds that a genus is represented in several successive valleys by allied species, sometimes feeding on the same, sometimes on different plants. In every such case it appeared that the valleys that are nearest to each other furnish the most nearly allied forms, and a full set of the varieties of each species presents a minute gradation of forms between the more divergent types found in the more widely separated localities. After giving reasons for the belief that this variation is not due to dif

ferences in their external conditions, Gulick concludes that the difference is due to a corre

sponding difference in the time of separation of each variety, and also to what he terms 'cumulative segregation,' 'segregate breeding,' and 'independent generation.' In his interesting essay on Physiological Selection (1886 and 1897), Romanes states that the essence of the principle consists in all cases of the diversifying effect of cross-infertility, whensoever and howsoever it may happen in particular cases to have been caused. (See PHYSIOLOGICAL SELECTION.) It is to be observed that this is but little different from Gulick's 'cumulative' or 'intensive' segregation. See EVOLUTION, paragraph Factors of Evolution; CLASSIFICATION OF ANIMALS, paragraph Species.

After all the careful work done by Gulick, it is yet to be doubted whether the chief or initial factors in the wonderful specialization which has taken place in the land shells of Oahu are not the result of migration into new regions, vary ing in natural conditions. For the present, then, Wagner's factors of migration into areas with differing conditions of life, and isolation, and the consequent prevention of intercrossing with the criginal or parent forms, may be accepted as the - essential causes of the origin of perhaps two

thirds to one-half of existing as well as extinct species.

BIBLIOGRAPHY. Ueber die Darwinische Theorie in Bezug auf die geographische Verbreitung der Organismen (Munich, 1868); The Darwinian Theory and the Law of the Migration of Organisms (Leipzig, 1868; trans. by Laird, London, 1873); Ueber den Einfluss der geographischen Isolirung und Colonienbildung auf die morphoLogischen Veränderungen der Organismen (Munich, 1870); Gulick, “On Diversity of Evolution Under One Set of External Conditions," in Journal of the Linnean Society (London, 1872); Divergent Evolution Through Cumulative Segregation (ib., 1888); "Divergent Evolution and the Darwinian Theory," in American Journal of Science (New Haven, January, 1890); "Intensive Segregation, or Divergence Through Independent Transformation,” in Journal of the Linnean Society (London, 1890); Romanes, "Physiological Selection," in Journal of the Linnean Society (ib., 1886).

ISOLD, ISOLDE, ISOND, ISOUD. See ISEULT.

ISOMERISM, î-som'ĕr-iz'm. See CHEMISTRY; VALENCY; CARBON COMPOUNDS; STEREO CHEMISTRY; CYANIC ACID; ALLOTROPY.

ISOMORPHISM, I'sô-môrʼfiz'm (from isomorphous, from Gk. ioos, isos, equal + μopón, morphe, form). The relationship existing be

tween solid substances which are similar in their chemical composition and constitution, have similar crystalline forms, and are capable of forming homogeneous mixed crystals ('solid solutions'), and each of which is capable of growing in a saturated solution of another, the latter then forming a mantle around the first as a nucleus. Ostwald proposes to define the relationship between two isomorphous substances as the capacity of one to cause immediate crystallization in crystal of any substance is capable of causing a supersaturated solution of another, just as a immediately. It must, however, be observed that its own supersaturated solution to crystallize while the relationship of isomorphism certainly exists, our knowledge of its intimate nature is

very vague, and neither of the above definitions gives adequate expression to all of the known facts. The ordinary carbonates of calcium (calcite), magnesium (magnesite), iron (siderite), manganese (rhodochrosite), and zine (smithsonite) all form crystals of the same crystal system, and for the most part of the same crystal class (see CRYSTALLOGRAPHY); and, further, their corresponding interfacial angles approach to the same values. Not all substances closely related in their chemical composition are isomorphous, and, exceptionally, substances which have no chemical relationship have similar symmetry of crystals and angles in close correspondence. (Such an accidental resemblance of the crystal forms of chemically unrelated substances is described as 'isogonism.') In the case of salts, the chemical component which seems mainly to condition the symmetry of the molecule is the acid radical, the metal having less influence upon the crystal's symmetry, though affecting the size of crystal angles. (See MORPHOTROPISM.) The metals of a series of isomorphous salts are said to be isomorphous elements, and it is found that for the most part

they are of the same or related groups of elements. See PERIODIC LAW.

first segment of the thorax is fused with the head, but the remaining seven are free, and bear limb-like appendages without gills. In females the basal joints of several of these appendages bear lamellæ, which form a brood-pouch for the eggs. There is never any carapace. The maxillipeds, of which there is only a single pair, usually fuse to form a sort of lower lip. The abdominal appendages are biramose, and serve for swimming and breathing; the most anterior pair are usually thick, and form an operculum which serves to protect the more delicate appendages behind. The heart is situated chiefly in the abdomen, but extends forward a short distance into the thorax. While most of the species lead a free life, some of the marine forms (Cymothoa, etc.) are parasitic on fishes or on other crustaceans, or bore into wood, etc. See illustration under GRibble.

When a substance has been found to form crystals of more than one kind it is said to be dimorphous, trimorphous, or polymorphous, the term dimorphous being used in a general sense to describe substances which exhibit three or more as well as two kinds of crystals. Sulphur crystallizes from fusion in long needle-like crystals of monoclinic symmetry, but from a solution in carbon bisulphide in orthorhombic crystals. Under other special conditions it assumes other kinds of symmetry. Carbonate of lime, which is generally found crystallized in nature as hexagonal (trigonal) crystals (calcite), is less frequently found in crystals belonging to the orthorhombic system, and with different physical properties from those of calcite. As explained above, calcite belongs in an isomorphous series with carbonate of magnesia, carbonate of iron, One group (Bopyrida) are parasitic, living carbonate of zinc, etc. Aragonite, on the other under the carapace of various shrimps. The fehand, is a member of a different isomorphous males of Bopyrus palæmoneticola (Packard) are group in which are carbonate of strontium, car- many times larger than the males, and are much bonate of barium, and carbonate of lead. A degenerated, the head being without eyes and double group of this kind connected by a dimor- appendages; they retain their position on their phous substance (carbonate of lime as calcite host by means of the sharp, hook-like legs around and aragonite) is known as an isodimorphous the edge of the body. The male in general apgroup or series. See CRYSTALLOGRAPHY; CHEM- pearance shows but slight modifications and is ISTRY; ATOMIC WEIGHTS. about one-fifth as large as the female, and is lodged partly out of sight under the ventral plates of its consort.

ISOPERIMETRIC FIGURES (from Gk. toos, isos, equal + Tepiμerpov, perimetron, perimeter, from repl, peri, around + μéτpov, metron, measure). Plane figures having equal perimeters. In the seventeenth century all problems which demanded the statement of a maximum or minimum property of functions were called isoperimetric problems. To the oldest problems of this kind belong especially those in which one curve with a maximum or minimum property was to be found from a class of curves of equal perimeters. That the circle, of all isoperimetric figures, gives the maximum area is said to have been known to Pythagoras. In the writings of Pappus a series of propositions relating to figures of equal perimeters is found. In the fourteenth century the Italian mathematicians also worked on problems of this kind. But Bernoulli (1696) and Euler (1744) applied the calculus of variations to these problems, and Euler gave a purely analytic treatment in his celebrated work, Methodus Inveniendi Lineas Curvas. This theory culminated in the calculus of variations, LaAn grange supplying the appropriate notation. illustration of problems of this class is that of Jakob Bernoulli-of all curves of the same length described on a given base, to determine one such that the area of a second curve, each of whose ordinates is a given function of the corresponding ordinate or arc of the first, may be a maximum or a minimum. See MAXIMA and MINIMA.

ISOP'ODA (Neo-Lat. nom. pl., from Gk. toos, isos, equal + Tous, pous, foot). An order of

malacostracous crustaceans of the section Arthrostraca, mostly aquatic-some marine, some inhabitants of fresh waters-but some terres

trial, inhabiting damp places, as the wood-louse and the like. They are easily recognized by the fact that the body is flattened dorso-ventrally, and many of them-e.g. the 'sowbug' or 'pillbug' (Porcellio)-have the habit of rolling up into a ball with the head tucked safely inward. The VOL. XI.-2.

Some of these forms are notably degenerate. The Isopoda are a comparatively small group, and are generally small individuals, few species reaching a length of one inch, except in the colosthe Caribbean Sea from a depth of nearly a mile. sal deep-sea Bathynomus giganteus, dredged in The colors are usually dull, blackish, gray, or brown; but some of the marine forms are highly colored, red or brown, according to the hue of

the seaweed they rest on.

Fossil isopods, though of little geological importance, are known from rocks as early as the the Jurassic limestones of Bavaria and other Upper Devonian and Carboniferous; also from Mesozoic formations. Most of them have some superficial resemblance to the marine Sphæroma,

and to the terrestrial wood-lice of modern time. See CRUSTACEA.

I'SOQUIN'OLINE. See QUINOLINE.

ISOSPONDYLI, î'sô-spõn’dí-li (Neo-Lat. nom. pl., from Gk. toos, isos, equal + oróvduλos, spondylos, vertebra). An order of teleost fishes, the soft-rayed fishes. They have the anterior vertebræ simple, unmodified; the mesocoracoid arch is always well developed, and the strong shouldergirdle is connected with the cranium. There are no auditory ossicles. The scales usually are cycloid, the ventral fins abdominal. large group, comprising the tarpons, lady fishes, herrings, shads, sardines, anchovies, menhadens, salmons, trouts, whitefishes, and related families, and, in the opinion of some, the Iniomi (q.v.) also. Consult Jordan and Evermann, Fishes of Northern and Middle America (Washington, 1896).

It is a

ISOTHERAL (f-sōth'ĕr-al) LINES, or ISOTHERÆ (from Gk. toos, isos, equal + Dépos, theros, summer). Lines that connect together places that have the same mean summer temperature.

ISOTHERMAL, î'sô-ther'mal (from Gk. toos, isos, equal + Oépun, thermē, heat). In physics, an isothermal is a line drawn on any diagram so as to represent the successive values of the properties of a body as it undergoes certain changes, the temperature being kept constant. Thus, if the properties of the body which are to be observed and noted are its pressure and volume, the isothermal curves are drawn on a diagram having pressure and volume as ordinates and abscissæ. The isothermals of a typical substance, carbonic-acid gas, CO2, in the form of

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vapor and liquid, are given in the accompanying figure. Considering any of the lower curvesi.e. the isothermals for temperatures less than 31° C.-it is seen to consist of three parts; the nearly vertical portion is the isothermal for the liquid; the horizontal portion, for the process of evaporation of the liquid; the curve at the right, which is nearly an hyperbola, is for the vapor after all the liquid has evaporated. The isothermals for temperatures higher than 31° C. do not have any horizontal portion, showing that as the gaseous substance is compressed at these temperatures it never condenses and becomes a liquid-if it did condense, the curve would become horizontal, because when the temperature is kept constant the pressure of the condensing vapor does not change. (See HEAT.) Therefore, if the gas is to be liquefied, it must be at a temperature lower than 31° C.-i.e. lower than the temperature corresponding to the first isothermal which does not have a horizontal portion. This temperature is called the 'critical' temperature.

ISOTHERMAL LINES, or ISOTHERMS. In meteorology, lines that connect places having the same temperature for a day, month, or for any given interval of time. Systems of isothermal lines for daily maps, as well as for monthly and annual means, present in a very graphic manner the prevailing temperature conditions, and are

therefore of universal use in meteorology. They seem to have been first used by Alexander von Humboldt in 1817; but lines of equal departure from normal values were independently used by Brands in his studies of the daily weather map and the storms of Europe. Isothermal lines coincide only accidentally, if at all, with small circles of latitude, owing to the great influence of the distribution of land and water on the temperature of the air. The temperatures observed at the respective stations must be corrected or reduced to the standard level surface of the globe, in order that they may be comparable with each other. This reduction introduces discrepancies, but there are many reasons for retaining it. The rate of reduction adopted by Hann and other climatologists is 0.50° C. per 100 meters, or 1° F. for 370 feet. If a chart has been constructed using this rate of reduction, and one should desire to know the temperature at the top of a mountain, whose altitude is given, we have but to read from the chart the temperature at sea-level, apply the reduction to the given altitude, and get at once approximately the temperature of the summit. The accuracy of this method is, however, limited by the fact that the rate of diminution of temperature varies so much that the adoption of an average rate is liable to lead us astray. Charts of isotherms for each month of the year and for the whole globe have been constructed, first by Buchan, and afterwards by the United States Weather Bureau, and were published in full in 1900 in elegant style in Bartholomew's Physical Atlas. Isothermal lines can be calculated and drawn for the upper levels of the atmosphere by using observations on mountain-tops and in balloons and kites. Lines of this character were first drawn by Hergesell for Europe for certain days in 1898-1900, on which sufficient data were collected by means of balloons and kites. These lines show that large variations in temperature occur at the highest attainable levels, and that the atmosphere in general is a mixture of masses of descending cold air and ascending warm air. See charts under TEMPERATURE, TERRESTRIAL; and DISTRIBUTION OF ANIMALS; also articles CLIMATE; DISTRIBUTION OF ANIMALS; METEOROLOGY.

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ISOUARD, 'zoo'är', NICCOLO, known NICCOLÒ DE MALTE in France (1775-1818). An Italian composer and musician, born in Malta. He was educated for the navy, and afterwards entered commercial life; but meanwhile he studied the piano under Pin in Paris, and harmony Later, under Vella and Azopardi in Malta. while in Italy, he received further instruction from Amendola, Sala, and Guglielmi. In 1795 he produced his first opera L'avviso ai maritati. The reputation gained by several works of the kind obtained for him the position of chapelmaster to the Order of Saint John of Jerusalem in Malta. In 1798 he went to Paris, and met there Rodolphe Kreutzer, who collaborated with him in two of his operas. One of his first successes was Michel-Ange (1802). He also became known as a pianist. He wrote for the Opéra Comique until Boieldieu's growing popularity, and the election in 1817 of that composer to the Academy, an honor which Isouard coveted, caused him to abandon himself to dissipation. The next year he died of consumption. He had much dramatic tact, his music is always

simple and gay, never trivial or vulgar, and he had the excellent librettos of Hoffmann and Etienne to work upon. Of his thirty-three operas, the following are the best known: Le médecin turc (1803); L'intrigue aux fenêtres (1805); Cendrillon (1810); Le siège de Mézières, with Cherubini, Catel, and Boieldieu (1814); Joconde (1814); Jeannot et Collin (1814); and Aladin, ou la lampe merveilleuse, completed by Benincori (1822).

ISPAHAN, 'spå-hän'. The former capital and one of the largest cities of Persia, situated on the river Zendeh Rud, over 200 miles south of Teheran, the present capital (Map: Persia, D 4). The surrounding country is of remarkable natural beauty, and presents a striking contrast to the half-ruined city. The ancient walls of Ispahan have a length of about 23 miles, but only a small part of the area inclosed is inhabited, the remainder being a succession of ruined castles, mosques, and schools, which testify to the former splendor of the city. The centre of the city is occupied by a magnificent plaza laid out by Shah Abbas, and formerly surrounded by fine structures. Of the few buildings which have survived the ravages of time, the palace of Shah Abbas, known as Chehel Situn, or Hall of Many Columns, is probably the finest. A row of twenty graceful columns extends along the front portal, supporting a magnificently ornamented roof. Behind the columns is a spacious hall with mirror-covered walls and a fountain in the centre. Besides this hall there is a large room containing six large oil paintings depicting scenes from the life of Shah Abbas. On the southeastern side of the plaza stands the great mosque, Mesjid-i-Shah, erected in the beginning of the seventeenth century, and presenting, even in its ruined state, a fine example of Eastern architecture. On the western side of the royal grounds is situated a magnificent palace known under the name of Hasht Behesht, or 'Eight Paradises,' built by Shah Suleiman at the end of the seventeenth century. It is surrounded by beautiful gardens ornamented with fountains. On the western side is the mosque of Sheikh-Lutfallah, with its dome of enameled tiles, and at the northwestern end is the entrance to the extensive covered bazaars of the city, which have a total length of over two miles.

The Zendeh Rud, on which the town is situated, is crossed by five bridges, of which that of Ali Verdi Khan is especially remarkable, both for its size and for its architectural beauty. Industrially Ispahan is still a town of some importance. Its chief products are silk, woolen, and cotton goods, jewelry, arms, leather goods, and footwear. The town derives also consider able commercial importance from its position on the main route from Abushehr to Teheran. A little way south of Ispahan is situated the Armenian settlement of Julfa, which contains the entire European colony of Ispahan. It was founded in the beginning of the seventeenth century, and at one time had an Armenian population of 30,000, which was reduced through persecution to about 2000. It has a number of Christian churches and several schools. The population of Ispahan is estimated at from 60,000 to 80,000. Ispahan is said by Persian writers to have been founded by some of the Jews who were led

into captivity by Nebuchadnezzar. It was a trading town of importance, and the capital of Irak, under the caliphs of Bagdad. It was taken by Timur in 1392, when 70,000 of the inhabitants are said to have been massacred. During the seventeenth century, under Shah Abbas the Great, it became the capital of Persia, and reached the climax of its prosperity. It is said to have had between 600,000 and 1,000,000 inhabitants. It was then the emporium of the Asiatic world; the merambassadors from Europe and the East crowded chandise of all nations enriched its bazaars, and its Court. In 1722 it was devastated by the Afghans, and some time afterwards the seat of government was transferred to Teheran (q.v.).

ISPICA, ĕ'spê-kå, VAL D'. A valley in Southeastern Sicily, five miles southeast of Modica. It is seven miles long, and is famous for its grottoes, containing graves. In the fourth century, numerous inscriptions show, these grottoes were used by Christians as tombs.

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ISRAELITES, iz'râ-ěl-its. See JEWS. ISRAËLS, és rá-als', JOSEF (1824-). Dutch genre painter, born at Groningen in North Holland. He is of Jewish parentage, and was intended for a commercial career, but he early showed a taste for art, and was sent to Amster

dam, where he studied under Kruseman and Pieneman. Afterwards he became a pupil of Picot and Scheffer, and of the Ecole des BeauxArts in Paris, under Delaroche. In 1848 he returned to Amsterdam, and for several years painted historical pictures, still influenced by his last master, Delaroche. His real style was not revealed until his return from Zandvoort, a fishing village near Haarlem, where he had gone for his health. He continued to live principally at Amsterdam until he settled at The Hague in 1870. In 1862 his pictures "The Cradle" and "The Shipwrecked Mariner," exhibited in London, excited much interest. "The Cradle," with its intimate charm, and touch of agreeable sentimentality, was typical of many of the interiors, both in oil and water-color, that he executed afterwards. An example of this later painting is "Expectation," in the Metropolitan Museum of Art, New York City. It is a moving, homely picture of the genre he made famous by "Interior of the Orphan Asylum at Katwijk" (1867); "The Frugal Meal;" "The Silent House," in the Glasgow Museum; "An Interior," in the Dordrecht Gallery; "Alone in the World," Amsterdam Gallery; "A Son of God's People," "Before Parting," "Through Darkness to Light." His "David Before Saul" is in a different manner. As he grew older, his work gained in breadth and poetic power. The studies of fisher-folk, by which he is equally well known, include the rather melodramatic "Shipwrecked Mariner;" "The Zandvoort Fisherman," in the Amsterdam Gallery; and his great canvas "The Toilers of the Sea," which with "Between the Field and Seashore," and "The Bric-a-brac Dealer," won medals of honor at the Paris Exposition of 1900. He also received a gold medal at the Universal Exposition of 1889. Israëls is often compared with Millet, but to Millet's repose he nearly always

added pathos. His general treatment is broad and realistic, and his color, at first pronounced, was afterwards modified with peculiar, misty atmospheric effects. Israels's etchings are notable for their simplicity and sureness of touch. Consult: Netcher and Zilchem, Josef Israëls,

l'homme et l'artiste (Amsterdam, 1891); Ma

ther, History of Modern Painting (New York,

1896).

ISRAFIL, és'rå-fel'. The archangel of music, who, according to later Mohammedan belief, will sound the last trump on the day of resurrection, standing upon the rock of the temple at Jerusalem calling mankind to the last judgment. His playing will be one of the delights of paradise. The name does not occur either in the Koran

or Traditions. He is, however, supposed by commentators to be the angel mentioned in Suras xx. 107, 1. 40, and liv. 6. Like much of the angelology of Mohammedanism, this represents a superstructure due to later Jewish and Christian influences.

ISSACHAR, is'så-kär. (1) One of the tribes of Israel, descended according to the Book of Genesis (xxx. 17) from Issachar, the ninth son of Jacob and fifth of Leah. The name is explained as meaning 'there is reward,' and is interpreted by the Yahwistic writer by a reference to the 'mandrakes' with which Leah hired' her husband from her sister Rachel (Gen. xxx. 16); by the Elohist as Leah's reward for giving her handmaid Zilpah to Jacob (xxx. 18). A plausible conjecture is that the real meaning is hired laborer,' and that the name is due to the subject condition of the tribe at some period of its history (cf. Gen. xlix. 14-15). The tribe's lot in Palestine included the Plain of Esdraelon, but the Canaanites were but imperfectly dis possessed. Deborah and Barak are supposed to have belonged to the tribe, also Baasha, third king of Israel (I. Kings xv. 27). The reference to Issachar in the blessing of Moses (Deut. xxxiii. 18-19) has been thought to refer to sanctuaries in the territory of the tribe which were visited by non-Israelites (probably Phoenicians) to the advantage of the Issacharites.

(2) A character in Dryden's Absalom and Achitophel, representing Thomas Thyme, murdered because of his attentions to Lady Elizabeth Percy.

ISSIK-KUL, ês'sēk-kōōl'. A lake in the Central Asiatic Province of Semiryetchensk, Russia, lying to the south of Lake Balkash (Map: Asia, G 4). It is about 38 miles in width and 112 miles long, with an estimated area of over 2000 square miles. It receives a number of small streams, and its water is brakish; its shores are low and sparsely inhabited. The chief settlement is Przhevalsk, situated on the eastern shore and named in honor of the famous explorer Przhevalsky.

ISSLAND, is'lånd. In the Nibelungenlied (q.v.), the Kingdom of Brunhilda.

ISSOUDUN, 'soo'den'. The capital of an arrondissement in the Department of Indre, France, situated on the river Théolle, on the railroad from Orleans to Limoges, 22 miles southwest of Bourges (Map: France, H 5). It has a municipal college, a library, and a museum, the latter installed in an ancient building known as the White Tower.

dates from ante-Roman times, but it has preserved few ancient remains, as it has often been ravaged by wars, and has been several times destroyed by fire. Population, in 1901, 14,222.

from OF. issir, eissir, to go out, from Lat. exire, ISSUE (OF. issue, eissue, essue, Fr. issue, to go out, from ex, out + ire, to go). In legal procedure, the stage of an action when, in the course of pleading, the parties come to a point which is affirmed by the one and denied by the other. The term is derived from exitus, and denotes that the pleadings have come to an end. The litigants are at issue. It is also used to designate the point or question thus raised by the pleadings. In this sense the issue may be one either of law or of fact. If the former, it is decided by the court without the intervention of a jury; if the latter, it is determined by a jury, or, in equity practice, by a judge. In some

of the States of the Union issues of both kinds may by consent of parties be tried by a referee. An issue of fact arises when a material matter of fact is asserted by one party and denied by the other. An issue of law arises when one party, admitting for the purposes of the issue that the facts alleged by his adversary are true, denies that they are sufficient to constitute a cause of action or a defence.

When a court of law or equity is sitting without a jury, it sometimes happens that a question of fact arises upon which the decision of a jury is desired. A fictitious suit is thereupon framed, involving the point in question, and brought to trial before a jury summoned for the purpose. The verdict rendered, being returned to the court, is accepted as a settlement of the issue of fact, and the trial of the cause out of which that issue grew thereupon proceeds. In some States a feigned issue in such cases is not required, the actual question as it arises being submitted to a jury by order of court. See GENERAL ISSUE; and consult the works referred to under PLEADING.

IS'SUS (Lat., from Gk. 'Iooós). An ancient seaport on a gulf of the same name (now the Gulf of Iskanderun) in Cilicia, Asia Minor. It possessed great strategic importance in ancient times on account of its position on the narrow defile leading from Syria into Cilicia. At Issus Alexander the Great overwhelmed Darius (B.C. 333). Nearby, Septimius Severus overthrew Pescennius Niger, his rival for the Imperial throne, A.D. 194, and in the neighborhood the Emperor Heraclius defeated the Persians in A.D. 622. The exact site of Issus has not been determined.

ISSY, ê'se'. A town in the French Department of Seine, situated about a mile and a half southwest of Paris, with which it is connected by a street railway. It has a seminary, a castle, and a home for the aged. There are manufacThe fortifications tures of silk, paint, oil, etc. of Issy suffered considerably during the siege of Paris in 1870-71, but have since been restored. Population, in 1901, 16,639.

IS'TER. The ancient name of the Danube in its lower course.

ISTHMIA, is'mi-å, or ISTHMIAN GAMES.
See ISTHMUS.

ISTHMIAN CANALS.
It has quarries of lithographic
CANAL; PANAMA CANAL.

stone and manufactures of textiles. The town

See NICARAGUA

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