Part 23

ALGAE (al'j[=e]), a nat. ord. of cryptogamic or thallogenous plants, found for the most part in the sea and fresh water, or on the surface of damp walls, rocks, the bark of trees, and in similar moist situations. They are either some shade of bluish-green, green, brown, or red colour. The higher forms have stems bearing leaf-like expansions, and they are often attached to the rocks by roots, which, however, do not derive nutriment from the rocks. A stem, however, is most frequently absent. The plants are nourished through their whole surface by the medium in which they live. They vary in size from the microscopic diatoms to forms whose stems resemble those of forest trees, and whose fronds rival the leaves of the palm. They are entirely composed of cellular tissue, and many are edible and nutritious, as carrageen or Irish-moss, dulse, &c. Kelp, iodine, and bromine are products of various species. The Algae are also valuable as manure. They are often divided into five orders: Diatomaceae, Confervaceae, Fucaceae, Ceramiaceae, and Characeae.

ALGAR'DI, Alessandro, one of the chief Italian sculptors of the seventeenth century; born 1602, died 1654. He lived and worked chiefly at Rome; executed the tomb of Leo XI in St. Peter's, a bronze statue of Innocent X, and a marble relief with life-size figures over the altar of St. Leo there.

ALGARO'BA-BEAN. See _Carob Tree_.

AL'GAROT, a violently purgative and emetic white powder, precipitated from chloride of antimony in water; it was used in medicine by the physician Victor Algarotus in the sixteenth century.

ALGAROT'TI, Francesco, Count, born in 1712, died in 1764, an Italian writer on science, the fine arts, &c. He lived for some years in France and for a long time in Germany, Frederick the Great of Prussia having made him chamberlain and count. He wrote _Neutonianismo per le donne_; _Saggi sopra le belle arti_, his principal work on art; poems, letters, &c. Algarotti's works published at Venice in 17 vols. (1791-4) and illustrated by Tesi and Novelli are a _chef-d'oeuvre_ of typography. Frederick the Great erected at Pisa a monument to his memory.

ALGARVE (al-g[.a]r'v[=a], meaning the land situated in the west), a maritime province of Portugal occupying the southern portion of the country, mountainous but with some fertile tracts. The title King of Algarve was held by the Kings of Portugal. Area, 1937 sq. miles; pop. 274,122.

ALGAU ([.a]l'gou), a name for the south-western portion of Bavaria and the adjacent parts of Wuertemberg and Tyrol, intersected by the Algau Alps. The Algau breed of cattle is one of the best in Germany.

ALGAZZALI ([.a]l-g[.a]z-[:a]'l[=e]), Abu Hamed Mohammed, an Arabian philosopher, Persian by birth; born 1058, died 1111. He was a most prolific author; an opponent of the prevailing Aristotelian philosophy of the day, and wrote against it the _Destruction of the Philosophers_, answered by Averroes in his _Destruction of the Destruction_.

AL'GEBRA (from the Arabic _al_, definite article, and _jabbara_, to make equal), a kind of generalized arithmetic, in which numbers or quantities and operations, often also the results of operations, are represented by symbols. Thus the expression xy + cz + dy^2 denotes that a number represented by x is to be multiplied by a number represented by y, a number c multiplied by a number z, a number d by a number y multiplied by itself (or squared), and the sum taken of these three products. So the _equation_ (as it is called) x^2 - 7x + 12 = 0 expresses the fact that if a certain number x is multiplied by itself, and this result made less by seven times the number and greater by twelve, the result is 0. In this case x must either be 3 or 4 to produce the given result; but such an equation (or formula) as (a + b)(a - b) = a^2 - b^2 is always true whatever values may be assigned to a and b. Algebra is an invaluable instrument in intricate calculations of all kinds, and enables operations to be performed and results obtained that by arithmetic would be impossible, and its scope is still being extended.

The beginnings of algebraic method are to be found in Diophantus, a Greek of the fourth century of our era, but it was the Arabians that introduced algebra to Europe, and from them it received its name. The first Arabian treatise on algebra was published in the reign of the great Caliph Al Mamun (813-33) by Mohammed Ben Musa. Italian merchants were the first algebraists in Europe, and in 1202 Leonardo Fibonacci of Pisa, who had travelled and studied in the East, published a work treating of algebra as then understood in the Arabian school. From this time to the discovery of printing considerable attention was given to algebra, and the work of Ben Musa and another Arabian treatise, called the _Rule of Algebra_, were translated into Italian. The first printed work treating on algebra (also on arithmetic, &c.) appeared at Venice in 1494, the author being a monk called Luca Pacioli da Bergo, a Minorite friar. Rapid progress now began to be made, and among the names of those to whom advances are to be attributed are Tartaglia and Geronimo Cardano. About the middle of the sixteenth century the German Stifel introduced the signs +, -, [sqrt], and Robert Recorde the sign =. The last-named wrote the first English work on algebra in 1557. Francois Vieta, a French mathematician (1540-1603), first adopted the method which has led to so great an extension of modern algebra, by being the first who used general symbols for known quantities as well as for unknown. It was he also who first made the application of algebra to geometry. Albert Girard, a Flemish mathematician in the seventeenth century, extended the theory of equations by the introduction of imaginary quantities. The Englishman Harriot, early in the seventeenth century, discovered negative roots, and established the equality between the number of roots and the units in the degree of the equation. He also invented the signs < >, and Oughtred that of x. Descartes, though not the first to apply algebra to geometry, has, by the extent and importance of his applications, commonly acquired the credit of being so. The same discoveries have also been attributed to him as to Harriot, and their respective claims have caused much controversy. He obtained by means of algebra the definition and description of curves. Since his time algebra has been applied so widely in geometry and higher mathematics that we need only mention the names of Fermat, Wallis, Newton, Leibnitz, De Moivre, MacLaurin, Taylor, Euler, D'Alembert, Lagrange, Laplace, Fourier, Poisson, Gauss, Horner, De Morgan, Sylvester, Cayley. Boole, Jevons, and others have applied the algebraic method not only to formal logic but to political economy.--BIBLIOGRAPHY: Chrystal, _Algebra_ (2 vols.); Hobson, _Trigonometry_; Hardy, _Pure Mathematics_; Whittaker and Watson, _Modern Analysis_.

ALGECIRAS ([.a]l-_h_e-th[=e]'r[.a]s) (perhaps Portus Albus of the Romans), a seaport of Spain, on the west side of the Bay of Gibraltar, a well-built town carrying on a brisk coasting trade. It was the first conquest of the Arabs in Spain (711), and was held by them till 1344, when it was taken by Alphonso XI of Castile after a long siege. Near it, in 1801, Admiral Sir James Saumarez defeated a Franco-Spanish fleet. Differences between France and Germany regarding Morocco led to a conference of European Powers here from 16th Jan.-7th April, 1906. Pop. 15,800.

ALGE'RIA, a French dependency in N. Africa, having on the north the Mediterranean, on the east Tunis, on the west Morocco, and on the south the Desert of Sahara; area, 122,878 sq. miles, or including the Algerian Sahara 343,500. The country is divided into three departments--Algiers, Oran, and Constantine. The coastline is about 550 miles in length, steep and rocky, and though the indentations are numerous, the harbours are much exposed to the north wind. The country is traversed by the Atlas Mountains, two chains of which--the Great Atlas, bordering on the Sahara, and the Little, or Maritime Atlas, between it and the sea--run parallel to the coast, the former attaining a height of 7000 feet. The intervals are filled with lower ranges, and numerous transverse ranges connect the principal ones and run from them to the coast, forming elevated tablelands and enclosed valleys. The rivers are numerous, but many of them are mere torrents rising in the mountains near the coast. The Shelif is much the largest. Some of the rivers are largely used for irrigation, and artesian wells have been sunk in some places for the same purpose. There are, both on the coast and in the interior, extensive salt lakes or marshes (_Shotts_), which dry up to a great extent in summer. The country bordering on the coast, called the _Tell_, is generally hilly, with fertile valleys; in some places a flat and fertile plain extends between the hills and the sea. In the east there are _Shotts_ that sink below the sea-level, and into these it has been proposed to introduce the waters of the Mediterranean. The climate varies considerably according to elevation and local peculiarities. There are three seasons: winter from November to February, spring from March to June, and summer from July to October. The summer is very hot and dry. In many parts of the coast the temperature is moderate and the climate so healthy that Algeria is now a winter resort for invalids.

The chief products of cultivation are wheat, barley, and oats, tobacco, cotton, wine, silk, and dates. Early vegetables, especially potatoes and pease, are exported to France and England. A fibre called _alfa_, a variety of esparto, which grows wild on the high plateaux, is exported in large quantities. Cork is also exported. There are valuable forests, in which grow various sorts of pines and oaks, ash, cedar, myrtle, pistachio-nut, mastic, carob, &c. The Australian _Eucalyptus glob[)u]lus_ (a gum tree) has been successfully introduced. Agriculture often suffers much from the ravages of locusts. Among wild animals are the lion, panther, hyena, and jackal; the domestic quadrupeds include the horse, the mule, cattle, sheep, and pigs (introduced by the French). Algeria possesses valuable minerals, including iron, copper, lead, sulphur, zinc, antimony, marble (white and red), phosphate, and lithographic stone.

The trade of Algeria has greatly increased under French rule, France, Spain, and England being the countries with which it is principally carried on, and three-fourths of the whole being with France. The exports (besides those mentioned above) are olive-oil, raw hides, wood, wool, tobacco, oranges, &c.; the imports, manufactured goods, wines, spirits, coffee, &c. The manufacturing industries are unimportant, and include morocco leather, carpets, muslins, and silks. French money, weights, and measures are generally used. The chief towns are Algiers, Oran, Constantine, Bona, and Tlemsen. There are about 2800 miles of railways opened; there is also a considerable network of telegraph lines.

The two principal native races inhabiting Algeria are Arabs and Berbers. The former are mostly nomads, dwelling in tents and wandering from place to place, though a large number of them are settled in the Tell, where they carry on agriculture and have formed numerous villages. The Berbers, here called Kabyles, are the original inhabitants of the territory and still form a considerable part of the population. They speak the Berber language, but use Arabic characters in writing. The Jews form a small but influential part of the population. Various other races also exist. Except the Jews, all the native races are Mahommedans. There are now a considerable number of French and other colonists, provision being made for granting them concessions of land on certain conditions. There are over 260,000 colonists of French origin in Algeria, and over 200,000 colonists natives of other European countries (chiefly Spaniards and Italians). Algeria is governed by a governor-general, who is assisted by a council appointed by the French Government. The settled portion of the country, in the three departments of Algiers, Constantine, and Oran, is treated much as if it were a part of France, and each department sends two deputies and one senator to the French chambers. The rest of the territory is under military rule. The colony costs France a considerable sum every year. Pop. of Algeria proper in 1911, 5,523,449; of the Algerian Sahara, 40,379.

The country now called Algeria was known to the Romans as Numidia. It flourished greatly under their rule, and early received the Christian religion. It was conquered by the Vandals in A.D. 430-1, and recovered by Belisarius for the Byzantine Empire in 533-4. About the middle of the seventh century it was overrun by the Saracens. The town of Algiers was founded about 935 by Yussef Ibn Zeiri, and the country was subsequently ruled by his successors and the dynasties of the Almoravides and Almohades. After the overthrow of the latter, about 1269, it broke up into a number of small independent territories. The Moors and Jews, who were driven out of Spain by Ferdinand and Isabella at the end of the fifteenth century, settled in large numbers in Algeria, and revenged themselves on their persecutors by the practice of piracy. On this account various expeditions were made by Spain against Algeria, and by 1510 the greater part of the country was made tributary. A few years later the Algerians invited to their assistance the Turkish pirate Horush (or Haruj) Barbarossa, who made himself Sultan of Algiers in 1516, but was not long in being taken by the Spaniards and beheaded. His brother and successor put Algiers under the protection of Turkey (about 1520), and organized the system of piracy which was long the terror of European commerce, and was never wholly suppressed till the French occupation. Henceforth the country belonged to the Turkish Empire, though from 1710 the connection was little more than nominal. The depredations of the Algerian pirates were a continual source of irritation to the Christian Powers, who sent a long series of expeditions against them. For instance, in 1815 a United States fleet defeated an Algerian one and forced the Dey to agree to a peace in which he recognized the American flag as inviolable. In 1816 Lord Exmouth with an English fleet bombarded Algiers, and exacted a treaty by which all the Christian slaves were at once released, and the Dey undertook for the future to treat all his prisoners of war as the European law of nations demanded. But the piratical practices of the Algerians were soon renewed.

At last the French determined on more vigorous measures, and in 1830 sent a force of over 40,000 men against the country. Algiers was speedily occupied, the Dey retired, and the country was without a government, but resistance was organized by Abd-el-Kader, an Arab chief whom the emergency had raised up. He began his warlike career of fifteen years by an attack on Oran in 1832, and after an obstinate struggle the French, in Feb., 1834, consented to a peace, acknowledging him as ruling over all the Arab tribes west of the Shelif by the title of Emir of Maskara. War was soon again renewed with varying fortune, and in 1837, in order to have their hands free in attacking Constantine, the French made peace with Abd-el-Kader, leaving to him the whole of Western Algeria except some coast towns. Constantine was now taken, and the subjugation of the province of Constantine followed. Meanwhile Abd-el-Kader was preparing for another conflict, and in Nov., 1838, he suddenly broke into French territory with a strong force, and for a time the supremacy of the French was endangered. Matters took a more favourable turn for them when General Bugeaud was appointed governor-general in Feb., 1841. In the autumn of 1841 Saida, the last fortress of Abd-el-Kader, fell into his hands, after which the only region that held out against the French was that bordering on Morocco. Early in the following year this also was conquered, and Abd-el-Kader found himself compelled to seek refuge in the adjoining empire. From Morocco Abd-el-Kader twice made a descent upon Algeria, on the second occasion defeating the French in two battles; and in 1844 he even succeeded in raising an army in Morocco to withstand the French. Bugeaud, however, crossed the frontier, and inflicted a severe defeat on this army, while a French fleet bombarded the towns on the coast. The Emperor of Morocco was at length compelled to agree to a treaty, in which he not only promised to refuse Abd-el-Kader his assistance, but even engaged to lend his assistance against him. Reduced to extremities Abd-el-Kader surrendered on 27th Dec., 1847, and was at first taken to France a prisoner, but was afterwards released on his promise not to return to Algeria. The country was yet far from subdued. The Kabyles, and the Arabs in the south, made protracted resistance, and rose again and again against the yoke which it was attempted to impose upon them. The numerous risings that successively took place thus rendered Algeria a school for French generals, such as Pelissier, Canrobert, St. Arnaud, and MacMahon. In 1864 MacMahon succeeded Pelissier as governor-general, and had as his first work to put down an insurrection. About this time the Emperor Napoleon III, who had visited the colony, introduced considerable modifications into the government, recognizing that the native races had grievances to complain of, and that the French rulers were in various ways astray in the methods of government adopted. Fresh disturbances broke out in the south nearly every year till 1871, when, owing to the Franco-Prussian war, a great effort was made to throw off the French yoke, the colony being nearly denuded of French soldiers. It was, however, completely suppressed, and in order to remove what was believed to be one principal cause of the frequent insurrections, a civil government was established instead of the military government in the northern parts of the colony. The southern parts, inhabited by nomadic tribes, are still subject to military rule. When the French took in hand the occupation of Tunis, a rising took place (in 1881) in the west of Algeria, under a chieftain who was able to inflict some loss and damage on the French forces and colonists, but with no permanent result. Since then quietness has generally prevailed in the colony, where the French, however, continue to maintain a considerable military force. Owing to this and other expenditure Algeria has always formed a burden on the resources of France. The great aid rendered by Algeria to France during the European War led the French Government to introduce new laws. The law of 4th Feb., 1919, gives French citizenship to all Algerian natives under certain conditions.--BIBLIOGRAPHY: M. D. Stott, _The Real Algeria_; Sir R. Lambert Playfair, _Handbook for Travellers in Algeria_ (Murray's Handbooks).

ALGESI'RAS. See _Algeciras_.

ALGHERO, or ALGHERI ([.a]l-g[=a]'r[=o], [.a]l-g[=a]'r[=e]), a fortified town and seaport on the north-west coast of the island of Sardinia, 15 miles south-west of Sassari; the seat of a bishop, with a handsome cathedral. One of the remarkable edifices of Alghero is the Casa Arbia, where Charles V was lodged. The necropolis of Anghelu Ruju, situated in the vicinity, was excavated in 1904.

ALGIERS (al'j[=e]rz; Fr., _Alger_), a city and seaport on the Mediterranean, capital of the French colony of Algeria, is situated on the west side of the Bay of Algiers, partly on the slope of a hill facing the sea. The old town, which is the higher, is oriental in appearance, with narrow, crooked streets, and houses that are strong, prison-like edifices. Its crowning point is the Kasbah, or ancient fortress of the Deys, about 500 feet above the sea, now serving as barracks. The modern French town, which occupies the lower slope and spreads along the shore, is handsomely built, with broad streets and elegant squares. It contains the Government buildings, the central military and civil establishments, the residence of the governor-general and the officials of the general and provincial Government, the superior courts of justice, the archbishop's palace and the cathedral, various other churches, including an English church and library, the great commercial establishments, &c. A fine boulevard built on a series of arches, and bordered on one side by handsome buildings, runs along the sea-front of the town overlooking the bay, harbour, and shipping. Forty feet below are the quay and railway-station, reached by inclined roads leading from the centre of the boulevard. The harbour is good and capacious, enclosed by piers or jetties, and otherwise improved at great expense, and it and the city are defended by a strong series of fortifications. Algiers is well provided with educational institutions, including high schools or colleges for law, medicine, literature, mathematics, and natural science; besides normal schools, an observatory, public library, &c. Algiers is in every way far the most important place in Algeria. There is a large shipping trade carried on, especially with Marseilles, Cette, and some of the Spanish ports. Trade routes from the interior and also railways centre in Algiers, and the exports include grain, wine, cattle, wool, ore, tobacco, fruit, olive-oil, &c. Algiers is now an important coaling station The city possesses widely-extended suburbs. The climate, though variable, makes it a very desirable winter residence for invalids and others from colder regions. Though warm, it is bracing. There is a considerable rainfall (average 29 inches), but the dry air and absorbent soil prevent it from being disagreeable. The winter months resemble a bright, sunny English autumn, while the heat of summer is not so intense as that of Egypt. The sirocco or desert wind is troublesome, however, during summer, but in the winter it is merely a pleasant, warm, dry breeze. Hailstorms are not infrequent, but frost and snow in Algiers are so rare as to be almost unknown. Pop. 172,397.

ALGIN, a viscous, gummy substance obtained from certain seaweeds, more especially those of the genus Laminaria. It can be utilized for all purposes where starch or gum is now required; may be used in cookery for soups and jellies; and in an insoluble form it can be cut, turned, and polished, like horn or vulcanite.

ALGO'A BAY, a bay on the south coast of the Cape Province, 425 miles east of the Cape of Good Hope, the only place of shelter on this coast for vessels during the prevailing north-west gales. It was the first landing-place of British immigrants in 1820. The usual anchorage is off Port Elizabeth, on its west coast, a place of large and increasing trade, but open on the east and south-east.

ALGOL', Arabic name of a star in the constellation Perseus (head of Medusa), remarkable as a variable star, changing in brightness from the second to the fifth magnitude.

ALGO'MA, a district of Canada, on the north of Lake Superior, forming part of the north-west portion of Ontario, rich in silver, copper, iron, &c.

ALGON'KINS, or ALGONQUINS, a family of North American Indians, formerly spread over a great extent of territory, and still forming a large proportion of the Indians of Canada. They consisted of four groups, namely--(1) the eastern group, comprising the Massachusetts, Narragansets, Mohicans, Delawares, and other tribes; (2) the north-eastern group, consisting of the Abenakis, &c.; (3) the western group, made up of the Shawnees, Miamis, Illinois, &c.; and (4) the north-western group, including the Chippewas or Ojibbewas, the largest of all the tribes.

ALGORISM, or ALGORITHMUS, in arithmetic, a word derived from the name of Algoritmi or Al-Khowarizmi, from whose works European scholars received much of their early information concerning Hindu numerals. The word is now used to designate any particular arrangement of numerical work.

ALGRAPHY. See _Lithography_.

ALGUACIL, or ALGUAZIL ([.a]l-gw[.a]-th[=e]l'), in Spain, an officer whose business it is to execute the decrees of a judge; a sort of constable. In ancient times the Alguacil was the great provost of the palace.

ALGUM. See _Almug_.

ALHA'GI. See _Camel's-thorn_.