of England, made many experiments with an aeroplane apparatus, which he whirled around on a circular track. His machine weighed 350 pounds, and had a series of aeroplanes arranged somewhat like the slats of a Venetian blind. These slats were 22 inches wide, and curved in imitation of the wing of an albatross. He constructed a propeller to drive this machine, but never succeeded in making it selfsustaining.

Notable investigations on atmospheric movements have been made by Helmholtz of Berlin, L. P. Mouillard of Paris, and Lord Rayleigh of England, each of whom has contributed within recent years to the literature on the subject. See also AERONAUTICS, Vol. I, pp. 185-207.

AEROPHORE. See COAL, Vol. VI, p. 73. AEROPHYTES, plants which derive all their sustenance from the air, as certain orchids and bromelias. Among the latter is the Tillandsia, or "long moss," of the South. For further description, see EPIPHYTES in these Supplements.

AEROSTATIC PRESS, a machine used for extracting coloring matter from dyewoods. A vessel pierced with holes is divided by a horizontal partition, the dyewood containing the coloring matter is laid upon this, and a perforated cover over it. An extracting liquid is then poured on the top and, the air being drawn from the under part of the vessel by a pump, the liquid is forced through the dyewood by the pressure of the air.

AEROSTATICS. That branch of the science of mechanics which treats of air at rest,—that is, with its particles in equilibrium. On the other hand, the science of pneumatics, as opposed to aerostatics, treats of air in motion.

ÆTIOLOGY (Gr. aitia, cause; logia, discourse), the science or philosophy of cause and causation, especially in the department of biology, which seeks to give a rational account of the forms, functions and history of organisms. The term is also used to describe the branch of medicine which investigates the causes and origin of diseases.

AETOMORPHÆ, the birds of prey; equivalent to the group called Accipitres or Raptores, by most writers. See ACCIPITRES, in these Supplements.

AFFIDAVIT, a written statement made under oath or affirmation before an officer authorized to administer oaths. The officers before whom affidavits are most frequently made are judges, officers of a court, or notaries. At common law notaries public had no authority, ex officio, to take affidavits, but by statute they are given this power throughout this country. An affidavit should contain the title of the cause if it is to be used in a legal proceeding, the venue, the signature of the party making the affidavit, the jurat or certificate of the officer, and the seal of the officer. An affiant is one who makes an affidavit. A supplemental affidavit is one made to correct an error or omission in a prior affidavit. A counter-affidavit is one made to deny or avoid the averments of another affidavit. See AFFIDAVIT, Vol. I, p. 226.

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expressly declares his intention to abide by his act. Implied affirmance is such as will be implied from the acts of the party. Affirmance by a court is where, on appeal, the judgment of the lower court is sustained.

AFFORESTATION. See Vol. IX, pp. 397-410; and FORESTRY, in these Supplements.

AFGHANISTAN. For general description, features and events prior to 1872, see AFGHANISTAN, Vol. I, pp. 227-241. Early in 1873 Shere Ali proclaimed Abdulla Ján as his heir apparent, and the following year confined his eldest son, Yakub Khan, as a close prisoner at Kabul. Shere Ali welcomed a political mission from the Czar, but declined to receive a similar English embassy. The British feared that the so called scientific frontier of India was in peril. Negotiations were fruitless. On Nov. 22, 1878, the British forces under General Roberts shelled Ali Musjid, and, rapidly pushing forward, occupied Jelalabad on December 20th. Shere Ali fled to Russian territory, and Yakub Khan assumed command of the tribesmen confronting the British. As the troops advanced, Shere Ali died, Feb. 20, 1879, Yakub being recognized as Ameer. He speedily concluded peace with the advancing British, and by the treaty of Gandamak, May 26, 1879, ceded the Kurum, Sibi and Pishin valleys to the invaders, and agreed to receive a permanent British resident at Kabul.

The British government agreed to defend Afghanistan from all foreign aggression, and the Khyber and Michni passes were left under their control as as part of the scientific frontier of India. This placed matters on a settled basis for a time, but in September of the same year the revolted troops of the Ameer treacherously attacked the British residency and massacred the small garrison, with Sir Louis Cavagnari, the resident, and all his staff. With 6,000 men Sir F. Roberts at once marched to Kabul. He defeated the Afghans on October 6th, at Charasiab, 12 miles from Kabul, and on the 12th entered the capital. Yakub abdicated on the 19th of October. In June, 1880, Ayub Kahn, the younger brother of Yakub Kahn, proclaimed a ghaza, or religious war, and marched for Kandahar, then held by British troops. After two severe reverses, in which the British lost over 1,000 men, Sir F. Roberts made the famous march to Kandahar with which his fame is permanently linked. Leaving Kabul on August 9th, he relieved Kandahar on the 31st, and the following day routed Ayub and captured his camp, artillery and baggage. Installing Abdul-Rahman Khan, who had been a pensioner of the British in Samarkand from 1870 to 1880, as Ameer, the British withdrew to the limits prescribed by the treaty of Gandamak.

The British troops were employed, before retiring from Afghanistan, to subject to the Ameer's control, in 1881, certain tribes who were proving refractory. A proposal by Russia, in 1882, to delimit the frontier of Afghanistan was received coldly in England. In July, 1884, however, a commission was appointed to demarcate the boundary between Afghanistan and the territory of the Turkomans. General Sir Peter Lumsden was nominated

the Russian. The line on which the commissioners were to be engaged was from Khoja Sakh, on the Oxus, to Sarakhs. But after the annexation of Merv and the preliminary surveys of M. Lessar in the valleys of the Khushk and Murghab, the Russian authorities took a different view. They contended that the Paropamisus was the true boundary of Herat, and that the district of Badghis, inhabited by Saryk Turkomans, who had proffered their allegiance to the Czar, lay outside Afghan territory. Questions of such grave moment, it was further stated, required to be settled by the two European governments before the commissioners could enter on their duties, and General Zelenoi was, without further explanation, sent to Tiflis. General Lumsden waited for him for four months on the Murghab, with an escort of 500 men, besides followers. In the mean while the Russian outposts were advanced SO as to include part of the debatable land. By their occupation of Zulfikar, 50 miles south of Pul-i-Khatun, the outposts of the two nations were brought into immediate contact, and it was only through the urgent remonstrances of General Lumsden that a collision was avoided. Matters were further complicated by the attack on Pendjdeh, near the fork of the Khushk and Murghab rivers, by a force under the command of General Komaroff, on March 30, 1885, and by his seizure of this important strategical position. During 1886 the demarcation of the frontier was proceeded with, and in April, 1887, the British and Russian commissioners met at St. Petersburg. After somewhat protracted negotiations, an agreement was effected, resulting in a compromise of the points at issue, concessions having been made on both sides. Russia obtained the valleys south of Pendjdeh for nine or ten miles in the direction of Herat; on the other hand, the Ameer of Bokhara waived his claims to the pasture-lands on the left bank of the Amu Daria, south of Khoja Saleh. Russia now touches the northwestern frontier of Afghanistan, and has developed her railway communication in this direction with extraordinary rapidity. Meanwhile Great Britain fortified and garrisoned Quetta, in Beluchistan, on the southern frontier of Afghanistan, and connected it with India by a railway extended (1887) as far as Pishin.

In 1887, on the completion of the Sibi-Pishin railway, the two districts from which the line takes its name were formally annexed to the Indian empire. Under the leadership of Ishak Khan, a cousin to the Ameer, another formidable rebellion broke out in Turkestan in the winter of 1888-89. This was speedily suppressed by Abdul-Rahman's forces, on which he went in person to Turkestan to affirm his rule and discipline the insurrectionists. This was done with such cruel severity as to provoke an outcry from Russia and a menacing concentration of her army on that frontier, the Ameer on his part suspending all friendly relations with Muscovy. was not until July, 1890, and after wreaking a terrible vengeance on his enemies, that AbdulRahman returned to his capital, his eldest son, Habibullah, having administered affairs at Kabul during the two years of his absence. At the same

It

time the Ameer was again on good terms with Russia, and in 1891 much jealousy was aroused in England by the discovery that there was a Muscovite outpost on the Little Pamir tableland. This approach toward the Indian frontier was hotly resented, and the question again came up of an Anglo-Russian demarcation of the territory in the Pamir. From the British standpoint this implied a secure Afghan barrier between India and Russia, while the latter power seemed to be cajoling both China and Afghanistan into a consent to her progress in the coveted direction. Meanwhile, in August, 1892, the Ameer advanced an appeal for advice from the Indian government, on the ground that he "could no longer endure the hostile action of Russia." Russia, nevertheless, continued to strengthen her position in the Pamir until the line of demarcation was finally settled.

The subsequent history of Afghanistan has been one of wars and rumors of wars, varied with the ever-approaching Russian advance and requests for frontier delimitation. Waziristan and Chitral have been the scenes of victory for two expeditionary forces, and in each case the natural difficulties and defenses of the country were the principal obstacles to oppose the advance of the troops. Chitral, on the accession of Lord Salisbury to power, was permanently garrisoned by native Indian troops, and the "land of mirth and murder," as an observant officer once aptly termed these hills, is secure in a settled form of government. The commission for the delimitation of the Indo-Afghan boundary line has made recent and rapid progress, and the Ameer, as an evidence of his friendship, in 1895 sent his second son, the Shahzada Nasrulla Khan, on an extended visit to the English court. In the Pamirs, "The Roof of the World," the boundary question has again cropped up, in the face of the continuous advance of the Muscovite outposts, and after continued diplomatic discussion the boundary has been ascertained and marked by a joint commission. The advance of Afghanistan in the hands of its present ruler has been marked. His mint is under the control of an Englishman, and manufactories are rapidly springing up in the principal towns.

The trade routes of Afghanistan are as follows: From Persia by Mashad to Herat ; from Bokhara by Merv to Herat; from Bokhara by Karchi, Balkh and Khulm to Kabul; from East Turkestan by Chitral to Jelalabad; from India by the Khyber and Abkhana roads to Kabul; from India by the Gumal Pass to Ghazni, and from India by the Bolan Pass and SindPishin railway to Kandahar.

No accurate statistics of the trade between Afghanistan and India have yet been obtained. Probably only one sixth of the freight carried by the SindPishin railway, amounting in value to Rx. 2,500,000 annually, can be classed as imports and exports between the two countries. The trade between the Kabul district and India during the past five years has been registered as follows: 1891-Rx. 1892-Rx. 1893-Rx. 1894-Rx. 1895-Rx. Imports from India.....459,870 653,639 610,500 405,200 270,575 Exports to India.. .208,600 218,120 220,850 188,800 152,791

Of the above imports, the principal articles are cotton goods, indigo, sugar and China leaf-tea.

The exports include horses, spices, assafoetida, fruits and nuts. The prohibitive duties on merchandise in transit levied by the Ameer do much to retard commerce between India and the country north of the Oxus.

AFRANCESADOS, a sobriquet applied to those Spaniards who gave their allegiance to the French and acknowledged Joseph Bonaparte as their king in 1808-13. Ferdinand VII took severe vengeance on the Afrancesados after his restoration.

*AFRICA, up to within the past few years, says the London Times, has hardly been needed by the rest of the world, except as a slave-market,- a land of barbarism, in which many of the native tribes carried on wars, of which the main object has been to take captives and sell them to the Semitic Arab dealers in slaves. The horrors of this bloody marketing of human beings gave occasion to European, chiefly British, interference, and, with this, exploration and colonization have slowly made Africa both known and sought, as a mass of lands needed for human progress, and promising to play a great part in the general economy of the world, as populations become organized, states are developed, industry is promoted, and civilization broadly planted.

A very recent authoritative estimate puts the value of the total commerce of Africa at £100,000,000, or $500,000,000, and pronounces this a miserable yield for 11,500,000 square miles. If, for instance, it is compared with South America, although large parts of it have been barely scratched, yet an area of 7,000,000 square miles in South America is carrying on a commerce valued at £160,000,000, or $800,

000,000.

SOUTH AFRICA. Statistics show that the grand total of South African commerce amounts to £17,358,000, or $86,790,000. Something less than one third of the whole continent of Africa, lying south of an equatorial boundary, will give a region as large as all Europe, and it is within this southern region that there are rapidly developing interests, calculated to make Africa count as one of the continental homes of great states and of advancing civilization. There has already set in a development corresponding to the development of the great Southwest of the United States, and in all probability many of those who are now living will see a United States of South Africa coming into existence, and promising to rank with the great nations of the world.

NORTH AFRICA. In North Africa there is a total population of about 17,000,000, of whom not more than 400,000 can be reckoned as white. The combined trade of Egypt, Tripoli, Tunis, Algeria and Morocco amounts to about £40,000,000, or $200,000,000 annually. The total area of these North African states is 1,250,000 square miles, but of this a large part-great wedges of desert-is wholly unproductive. Egypt, for example, has an area of 400,000 square miles, while all that it produces is yielded by only about 13,000 square miles. In all the other African states along the Mediterranean there are great tracts of desert. The people of these states are fairly high in the scale of civilization. They till the soil industriously, they rear cattle, they are skilled in manufactures of a simple kind, they are keen traders, * Copyright, 1896, by The Werner Company.

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and they have many wants which Europe can supply. All these lands, in spite of the drawbacks of the desert regions, are capable of being developed far beyond their present yield, but they are not adapted in climate to become the home of European laborers, at least not those native to central and northern Europe. Eminent French engineers have proposed to create in the depressed area of the Sahara to the south of Algeria an inland sea, by cutting through a ridge, 13 miles across and 150 feet high, into a depression from which, by one or two smaller cuttings, other depressions will lead to the great basin, the area of which is about 3,100 square miles, with an average depth of 78 feet. The belief of the projectors of this scheme is that the lake thus created would greatly improve the rainfall for the Sahara.

PARTITION. It is within about a single generation that a great part of North Africa, and nearly the whole of South Africa, has been explored and taken nominal possession of by various European powers, for the most part without resort to conquest, and with such beneficial results as improved relations among tribes, cessation of chronic tribal warfare and of cannibalism, extinction of bloody rites connected either with ancestral worship or with witchcraft, and the gradual suppression of the slave-trade. The systematic work of South African research began with Livingstone's discovery of Lake Ngami in 1849.

The large chapter in the history of African research which ended with the death of Livingstone in 1873, with the explorations of Burton and Speke (1857-58), of Speke and Grant (1860-62), and of Baker (1869-73), prepared the way for H. M. Stanley's expedition of 1875-77, with results scarcely surpassed in the annals of geographical research. Stanley especially opened to knowledge, by this expedition, the immense basin of the Congo, a river second only to the Amazon in volume and extent of navigable waters, and affording, through tropical Africa, from Stanley Falls to Stanley Pool, nearly a thousand miles of navigable waterway, calculated to profoundly benefit the Bantu populations of this boundless region. Stanley's Emin Pasha relief expedition in 1887-89 proceeded up the Congo and its Aruwimi affluent, and thence through the equatorial lake region to Zanzibar.

The political conquest of Africa has already so far progressed (1896) that the whole of the southern, and nearly all of the northern, divisions of the continent are virtually European dependencies. To a very large extent the Arab power, carrying everywhere Mohammedanism and the slave-trade, and until recently threatening to overrun the whole continent, has been arrested, driven back, and to a large extent broken. The International Anti-Slavery Congress of Brussels pledged the civilized world to the repression of the slave-trade; and, through charters to powerful commercial associations granted by various European powers, provision has been made for running railways through the country, launching steamers on navigable inland waters, and opening in every direction lines of civilized trade and of humane development. The partition of the continent was practically completed by the conventions entered

The central Sahara region has been very imperfectly explored. Between the various routes running north and south, everywhere remain vast spaces un visited; in fact, the actual extent of the Sahara as yet even roughly surveyed hardly exceeds 200,000 square miles. Recent exploration fails to confirm the formerly prevalent notion of the marine origin of the Great Desert. Not only does the Sahara stand at a present mean altitude of over 1,400 feet above the surrounding waters, but there are unmistakable indications that within comparatively recent geological times it stood very much higher, probably as high as the southern section of the continent, say from 3,000 to 4,000 feet above the sea. This reduction of altitude is mainly due to atmospheric agencies affecting the change of temperature between day and night, and to the mechanical action of the wind violently driving the sands over the face of the rocks. Owing to the intense dryness of the air, and consequent rapid radiation of the heat from the burning surface of the ground after sunset, the temperature changes from over one hundred degrees Fahrenheit, to one or two degrees below freezing-point at night. This promotes rapid disintegration of the rocks. They are heated and expand under the fierce solar rays, and are then broken up by the sudden shrinkage caused by the cold at night. The disintegrated particles, violently driven by the wind, also have a wearing effect upon all the exposed rocky surfaces. It is estimated that the mean altitude of the desert plateau has been lowered probably 1,500 feet during and since Quaternary times. The rocks of the region appear to have been of sedimentary freshwater origin. They show not only extreme fineness, but a mixture of many clay particles, and, unlike seashore sands, they are very fertile wherever sufficient water can be obtained. In the Tuggurt district, on the northern verge of the desert, and also elsewhere, the sinking of numerous artesian wells has already brought extensive tracts under cultivation, and in some places the palm groves have largely encroached on the surrounding wastes. In In many districts, however, the disintegrated fragments of stone, not yet reduced to a fine powder, give a hard, shingly surface, with no possibility, for ages to come, but of absolute sterility.

The Sahara is nowhere a vast level plain strewn with sands; the general level is frequently broken by mountain masses and ranges of moderate elevation, or by deep, although now dry, river valleys and depressions of all kinds, below which, at no great depth, abundant water may frequently be found. It is roughly estimated that the actual extent of fine sand is less than one half, or even less than one third, of the entire Sahara surface. In whatever direction the Sahara is approached, the traveler has to ascend, not descend. It never was a marine basin capable of being transformed again to an inland sea by a series of engineering operations; it is rather an elevated plateau which stands at a mean altitude of from 2,100 to 1,400 feet, nowhere falling to, or below, sea-level except in the Siwah district, on its extreme northeastern verge, and in the Shott Melrhir basin, south of Algeria. A feature of the Sahara are

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the sand-dunes, disposed in long parallel, or nearly parallel, ridges, varying in height from 50 to 400, or even 500, feet. Their appearance is that of continual drifting and shifting, and of sand-storms sufficient to swallow up whole caravans, but this, even in the fiercest wind-storms, is an appearance only. The sand-hills are determined by moisture coming up from below, making the sand wet and heavy, and from year to year they are very little changed, although the surface dry sand may be in continual commotion. This view of the sand-hill regions becomes a guide to the sinking of wells, and proves that they are not absolutely irreclaimable.

Despite the generally desolate character of the Sahara, some important centers of trade and population occur, both on the northern and southern margin, and even in one or two central parts of the western region of interminable sand-hills. Such are, as we go from northeast to southwest, the towns and oases of Tuggurt, Wargla, Gardaia, Metlili, El-Golea, and in the extreme southwest, the Tuat oasis, including the flourishing settlements of Tidikelt, with its capital, In-Salah, in the Wad Saura basin. The eastern region of dunes, or sand-hills, although now absolutely uninhabitable, shows numerous buried prehistoric stations, known to the Arabs. Ahaggar, or Hoggar, occupying very nearly the geometric center of the Sahara, viewed as a whole, consists of a series of superimposed plateaus rising in terraces from 1,600 to over 6,500 feet. The circular central mass which forms its base has a circuit of over 370 miles. Its highest crest, with the twin peaks Hikena and Watellen, wears a mantle of snow in winter.

The

The western Sahara corresponds, in the absence of high ranges, prominent mountain masses, and extensive habitable tracts, to the still more arid and monotonous Libyan Desert, in the extreme east. The line dividing it from the central Sahara coincides with the now dried-up valley of the Messaura. whole region west of this valley, some 800 square miles in superficial area, consists almost exclusively of interminable sand-hills, or sand-wastes, traversed here and there by low, rocky ridges, sinking in the central parts to the great El-Juf depression, and attaining in the Aderer Heights a moderate elevation of 1,8c0 or 2,000 feet. There are no groups of oases on the trade routes through it between Morocco and Timbuktu, and but for the wells occurring along the line of march at greater or less intervals, travel would be impossible.

Negro populations and rule formerly extended over the greater part of the Sahara, and at some points even approached the Mediterranean seaboard, but for 300 years no negro people has held political power, and in many districts the primitive negro populations have disappeared, while in others they still persist, and have been added to by importations of slaves from the Soudan. The dominant tribes everywhere are Mohammedan, of either Hamitic or Semitic stock. The Hamites comprise the Tibus in the extreme east, and Tuaregs (Berbers) in the central and western regions. The Semites, mainly confined to the western Sahara, are all intruding nomads of Arab descent. What are termed Moors