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these catastrophes) was the violence of the rains produced by the evolution of aqueous vapor, that torrents of water descended the cone, and, becoming charged with impalpable volcanic dust, rolled along loose ashes, acquiring such consistency as to deserve the appellation of aqueous lava. A brief period of repose ensued, which lasted only until the year 1666, from which time to the present, there has been a constant series of eruptions, with rarely an interval of rest exceeding ten years. The modern lavas of Vesuvius are characterized by a large proportion of augite. When they are composed of this mineral and feldspar, they differ in composition but slightly from many of the trap-rocks. (See Trap.) They are often porphyritic, containing disseminated crystals of augite, leucite, or some other mineral, imbedded in a more earthy base. These porphyritic lavas are often extremely compact. In the lava currents of central France (those of Viverais), the uppermost portion, often forty feet or more in thickness, is an amorphous mass passing downwards into lava, irregularly prismatic; and under this there is a foundation of regular and vertical columns, in that part of the current which must have cooled most slowly. A great variety of minerals are found in the lavas of Vesuvius and Somma. Augite, leucite, feldspar, mica, olivine, specular iron, idocrase, garnet and sulphur are most abundant. It is an extraordinary fact, that, in an area of three square miles round Vesuvius, a greater number of mineral species have been found than in any spot, of the same dimensions, on the surface of the globe. Many of these are peculiar to this locality. A small part of the ejected matter, however, remains so near to the volcanic orifice. A large portion of sand and scoriæ is borne by the winds and scattered over the surrounding plains, or falls into the sea; and much more is swept down by torrents into the deep during the intervals, often protracted for many centuries, between eruptions. These horizontal deposits of tufaceous matter become intermixed with sediment of other kinds,and with shells and corals, and, when afterwards raised, form rocks of a mixed character, such as tufas, peperinos and volcanic conglomerates. Besides the ejections which fall on the cone, and that much greater mass which finds its way gradually to the neighboring sea, there is a third portion, often of no inconsiderable thickness, composed of alluvions, spread over the valleys and plains, at small distances from the volcano. Im
mense volumes of aqueous vapor are evolved from a crater during eruptions, and often for a long time subsequently to the discharge of scoriæ and lava. These vapors are condensed in the cold atmospliere surrounding the high volcanic peak; and heavy rains are caused sometimes even in countries where, under other circumstances, such a phenomenon is entirely unknown. The floods thus occasioned sweep along impalpable dust and light scoriæ, till a current of mud is produced, which is often more dreaded than an igneous stream, from the greater velocity with which it moves. After Vesuvius, the most authentic records relate to Ætna, which rises, near the sea, in solitary grandeur, to the height of nearly 15,000 feet, the mass consisting chiefly of volcanic matter ejected above the surface of the water. The base of the cone is eighty-seven miles. Etna appears to have been in activity from the earliest times of tradition. Thucydides informs us that between the colonization of Sicily by the Greeks and the commencement of the Peloponnesian war (B. C. 431), three eruptions had occurred. A great eruption occurred in the year 1669. The lava, after having overflowed fourteen towns and villages, some having a population of between 3000 and 4000 inhabitants, arrived, at length, at the walls of Catania. These had been purposely raised to protect the city; but the burning flood accumulated till it rose to the top of the rampart, which was sixty feet in height, and then fell in a fiery cascade, and overwhelmed part of the city. The wall, however, was not thrown down, but was discovered long afterwards by excavations made in the rock by the prince of Biscari; so that the traveller may now see the solid lava curling over the top of the rampart, as if still in the very act of falling. This great current had performed a course of fifteen miles, before it entered the sea, where it was still 600 yards broad and 40 feet deep. A gentleman of Catania, named Pappalardo, desiring to secure the city from the approach of the threatening torrent, went out with a party of fifty men, whom he had dressed in skins to protect them from the heat, and armed with iron crows and hooks. They broke open one of the solid walls which flanked the current near Belpasso, and immediately forth issued a rivulet of melted matter, which took the direction of Paternò; but the inhabitants of that town, being alarmed for their safety, took up arms, and put a stop to further operations. In 1811, the great crater testified, by its violent detonations,
that the lava had ascended to near the summit of the mountain, by its central duct. A violent shock was then felt, and a stream broke out from the side of the cone, at no great distance from its apex. Shortly after, other streams, to the number of six, broke out in succession, still lower down the mountain, but all in the same straight line. In 1819, three large mouths opened very near those which were formed in the eruptions of 1811, from which flames, red-hot cinders and sand were thrown up, with loud explosions. A few minutes afterwards, another mouth opened below, from which flames and smoke issued; and finally, a fifth, lower still, whence a torrent of lava flowed, which spread itself, with great velocity, over the valley Del Bove. This stream flowed two miles in the first twenty-four hours, and nearly as far in the succeeding day and night. As the last example of modern volcanic eruptions, we shall mention that of Jorullo, in Mexico, in 1759. The plain, which was the site of the eruption, is thirty-six leagues from the sea, and, at the time of the eruption, was occupied by fertile fields of sugar-cane and indigo. In the month of June, hollow sounds, of an alarming nature, were heard, and earthquakes succeeded each other for two months, until, in September, flames issued from the ground, and fragments of burning rocks were thrown to prodigious heights. Six volcanic cones, composed of scoriæ and fragmentary lava were formed on the line of a chasm which ran in the direction from north-north-east to south-south-west. The least of these cones was 300 feet in height; and Jorullo, the central one, was elevated 1600 feet above the level of the
A subsequent eruption of Jorullo happened in 1819, accompanied by an earthquake. The city of Guanaxuato, distant about 140 miles from Jorullo, was covered with ashes, to the depth of six inches, from this eruption. During the last century, about fifty eruptions are recorded of the five European volcanoes, Vesuvius, Etna, Volcano, Santorin and Iceland; but many beneath the sea, in the Grecian Archipelago, and near Iceland, may, doubtless, have passed unnoticed. If some of them produced no lava, others, on the contrary, like that of Skoptar Jokul, in 1783, poured out melted matter for five or six years consecutively. Now, if we consider the active volcanoes of Europe to constitute about a fortieth part of those already known on the globe, and calculate that, one with another, they are
about equal in activity to the burning mountains in other districts, we may then compute that there happen on the earth about 2000 eruptions in the course of a century, or about twenty every year, or .one in eighteen days. However inconsiderable, therefore, may be the superficial rocks, which the operations of fire produce on the surface, we must suppose the subterranean changes now constantly in progress to be on the grandest scale. The loftiest volcanic cones must be insignificant when contrasted with the products of fire in the nether regions. One of the earliest hypotheses to account for volcanic eruptions is that which attributes them to the eructations of a perpetual central fire, to which, however, the nature of the lava, the method of its projection, and, above all, the known laws of the communication of heat, are insurmountably opposed. The sudden evolution of steam has also frequently been resorted to. They have also been referred to the ignition of beds of coal; and Werner supposed that the fire thus produced fused the circumjacent rocks, and formed lava. Others have called sulphur, pyrites, petroleum and bitumen to their aid, but have sought in vain for the necessary supply of oxygen, without which these combustibles could not perform their required part; and, indeed, if we grant an unlimited supply of that element, the projectile force-the vaporstill remains to be accounted for. Others have imagined a great depôt of electric matter, pent up in certain submarine and subterranean caverns, and occasionally sallying forth to fuse and blow up the surrounding materials. The most plausible theory of volcanoes is that suggested by sir H. Davy, soon after he had discovered the nature of the earthy and alkaline bodies. Indeed, it enables us, in most cases, upon just principles of sound analogy, to explain their origin; for lava consists of earthy and alkaline bodies, ejected in intense ignition; and it is associated with vapor, with explosions of hydrogen gas, with the production of nitrogen; and, in short, there is every concomitant circunstance to lead to the conclusion, that there exist, in the bowels of the earth, masses of those highly inflammable metallic bodies, constituting the bases of the earths and alkalies; and these and water are essential requisites for the production of the phenomena that precede, accompany and follow the eruption of volcanoes: they may be referred to, as accounting for the earthquakes, the explosions and the gaseous products; and
they are the only agents, with which we are acquainted, capable of fulfilling all the requisites. How or where these bodies exist, at what depths, in what quantity, and how accessible to water, are questions that we cannot solve; but it is a curious fact, that water is always found connected with volcanoes. Vesuvius, Ætna and Hecla are upon the verge of the sea; and in the vicinity of the burning mountains of the Cordilleras there are lakes; and it has been observed, that springs and lakes suddenly dry up previous to the active eruption of a volcano. VOLGA. (See Wolga.)
VOLHYNIA; a government of the Russian empire, between the governments of Grodno and Podolia; square miles, 29,300; population, about 1,500,000. While Poland was independent, Volhynia formed a province of that kingdom, which bordered with the Ukraine on the southeast. The soil is fertile, producing wheat and rye, and its pasture lands are extensive; but a great part of the surface is forest. From its frontier situation, it has often been exposed to the evils of invasion. Since 1793, it has been in the possession of Russia. Volhynia was in insurrection in 1831, but shared the fate of Poland, when that unfortunate country was again trampled under foot by the victorious barbarians. (See Poland, and Russia.)
VOLITION. (See Will.)
VOLNEY, Constantine Francis Chasseboeuf, count de, peer of France, a celebrated French writer, was born at Craon, in Brittany, in 1755. Inspired, at an early age, with a desire to visit foreign countries in search of knowledge, he no sooner became master of a small patrimonial estate, than, he converted it into money, and embarked for the Levant, travelled through several parts of Egypt and Syria, and, after a residence for some time in a Maronite convent on mount Libanus, for the purpose of studying the Oriental languages, returned to France, whence he had been absent more than two years. The fruits of his inquiries appeared in his Voyage en Syrie et en Egypte (2 vols., 8vo.), which was transated into English, Dutch and German. This work procured him much reputation; and, taking up his residence at Auteuil, near Paris, he became intimately connected with some of the most eminent among his literary contemporaries. On the convocation of the states-general, in 1789, Volney was elected a deputy from the tiers etat of Anjou, when he embraced the cause of liberty, and frequently
appeared with advantage as a public speaker. In 1791, he published his deistical work, entitled Les Ruines, ou Méditations sur les Révolutions des Empires. After the conclusion of the sessions of the national assembly, he accompanied M. Pozzo di Borgo to Corsica, where he had projected some agricultural improvements. He made attempts to establish in that island the cultivation of the sugarcane, indigo, and other tropical plants; but he was unsuccessful. Returning to Paris, he suffered persecution under the reign of terror; and, after ten months' imprisonment, the fall of Robespierre restored him to liberty. In November, 1794, he was appointed professor of history at the normal school; and the course of lectures on the philosophy of history which he delivered, and which was published and translated into English, added considerably to his reputation. In 1795, he made a voyage to the U. States of America; and he would probably have settled in America, had not the prospect of a war with France induced him to return home in the spring of 1798. After the revolution which elevated Bonaparte to the consulship, he was nominated a senator; and it is said the office of second consul was designed for him, but his political opinions prevented the appointment from taking place. In the senate, he coöperated with Lanjuinais, Cabanis, Destutt de Tracy, Collaud, Garat, and others, whose influence was constantly exerted in the cause of freedom. After the restoration, Volney, by a decree of the fourth of June, 1814, was designated a member of the chamber of peers, where he remained faithful to his principles, always appearing among the ardent defenders of the rights of the nation. His death took place at Paris, in 1820. Besides the works already mentioned, he published Simplification des Langues Orientales, ou Methode nouvelle et facile d'apprendre les Langues Arabe, Persane et Turque, avec les Caractères Européens (1795, 8vo.); Tableau du Climat et du Sol des Etats Unis d'Amérique (1803, 2 vols., 8vo.), with a Vocabulary of the Language of the Miamis; Chronologie d'Herodote conformé à son Texte (1808, 2 vols., 8vo.); Recherches nouvelles sur l'Histoire Ancienne (1814-1815, 3 vols., 8vo.). His Euvres complètes, with his Life, appeared at Paris, in 1821, in 8 vols.
VOLPATO, Giovanni, an engraver, born at Bassano, in 1733, spent his early years in executing drawings for embroidery. Having acquired the use of the burin, without any
instruction, he afterwards went to Venice, where he executed engravings, in connexion with Bartolozzi, for Wagner, a picture dealer, and finally left Venice for Rome. Here a society of amateurs, at the head of whom was Ercole Bonajuti, had been formed for the purpose of procuring engravings of Raphael's works in the Vatican. The drawings of the Spanish painter La Veja, in eighty sheets, which had been prepared by a labor of three years for cardinal Silvio Valenti, and which had been bequeathed by the cardinal Luigi Valenti to the Vatican library, were made the basis of this work. Volpato was employed in its execution, and soon became distinguished among the artists connected with him. The six sheets executed by him are of the highest merit. They reproduce, as far as is possible in a small space, the impression of the original, and prove how fully the artist appreciated the pictorial merits of those great paintings, by his masterly distribution of light and shade. The most skilful union of the burin with the dry-point could alone have enabled him to accomplish this difficult task in a work of such extent. The publication of Raphael's loggie and arabesques placed Volpato at the head of a school of design, and gave him the honor of having rendered the productions of that great master more generally known, and of having awakened a purer taste among engravers. Accuracy of execution, and attention to the pictorial effect, so far as it depends not upon coloring, but upon light and shade, are the distinguishing merits of his school, from which proceeded Raphael Morghen (q. v.), at first the pupil, afterwards the friend, and finally the sonin-law of Volpato. Gavin Hamilton, the companion of his Socratic suppers, at which Canova also used to be present, was not without influence upon the taste of the artist. Volpato died in 1803, and Canova honored the memory of his friend and benefactor by a relief, which is placed in the hall of the church of the Apostles in Rome.
VOLSCI; an Ausonian tribe, which resided, before the foundation of Rome, in the ancient Latium (now Campagna di Roma). They had a republican government. Livy calls them the eternal enemies of Rome. Their principal city was Antium, the ruins of which are to be seen in the neighborhood of cape Angio. Corioli, from which Coriolanus derived his surname, was another city of theirs. After having several times endangered the Roman
state, they were conquered, and disappeared from history, like the other tribes of Latium.
VOLTA, Alessandro, descended from a respectable family of Como, was born in that place, in 1745, and died there in 1827. While pursuing his studies at Como, he displayed not less inclination for the poetic art than for the severe sciences, and composed a fine Latin poem upon physics. But he soon after devoted himself entirely to physical inquiries, and laid the foundation of his fame in two treatises, published in 1769 and 1771, in which he gave a description of a new electrical machine. In 1774, Volta became rector of the gymnasium in Como, and professor of physics, and, in 1779, was transferred to Pavia. Here he occupied himself entirely with electrical researches. He had previously (1777) invented the electrophorus, and his invention of the electroscope was also an important improvement. (See Electricity.) His observations upon the bubbles which arise from stagnant water, led him also to some valuable discoveries in regard to gases. The electrical pistol, the eudiometer, the lamp with inflammable air, the electrical condenser, and other inventions, are among his claims to renown. next turned his attention to some of the atmospherical phenomena, as the nature of hail, &c., and subsequently increased his reputation by the discovery of the Voltaic pile (see Galvanism), and, in 1782, made a tour through France, Germany, England and Holland, on which occasion he was treated with great respect by Haller, Joseph II and Voltaire. On his return to Italy, he introduced the cultivation of the potato into Lombardy. 1794, he received the Copleian medal from the royal society of London, on account of his paper upon the condenser; and, in 1801, his electric apparatus attracted so much notice in France that the first consul made him a present of 6000 francs. . He was subsequently deputy from the university of Pavia to the consulta held at Lyons, and Napoleon conferred upon him the cross of the legion of honor, and the order of the iron crown. In 1815, the emperor Francis appointed him director of the philosophical faculty in the university of Pavia. As a man, Volta was simple, modest and religious, a good father and citizen. Antinori edited a collection of his works (Opere di Volta, Florence, 1816, 5 vols.), and professor Zuccala published a eulogy upon him (Elogio di Volta) in 1827.
VOLTAIC PILE. (See Galvanism.) VOLTAIRE, Francis Marie Arouet de. If any man ever showed the natural sovereignty of the intellect, and its superiority to all earthly splendor, it was this distinguished man, who, in a nation, and at a time, when the learned and scientific were considered in the light of upper domestics of the great, undertook to secure for them an independent station. His influence was felt throughout Europe; and never did a man, by the force of his writings, obtain such power over his nation. Voltaire was born at Chatenay, near Paris, Feb. 20, 1694. His father, Francis Arouet, notary of the Châtelet, and finally treasurer of the chamber of accounts, possessed considerable property, so that he was enabled to give his son an excellent education. Voltaire received his first instruction in the Jesuits' college of Louis XIV., under Porée and Le Jay. Here he displayed talents which warranted the highest expectations. In his third year he was able to repeat the fables of La Fontaine, and, somewhat later, recited, from memory, a poem of Rousseau (La Moisade), before the celebrated Ninon de l'Enclos, who was so much pleased with the talent of the boy, that she left him a legacy of 2000 livres to purchase a library. According to the custom of the time, he was obliged to leave the family name to the eldest son, and therefore assumed that name which has since become so famous. His father wished to see him a lawyer and advocate ; but his love of literature and general study did not allow him long to devote himself to the law. He wrote poetry-continually, and cultivated his talents in the company of men of much accomplishment and wit, but of little principle; such as Chaulieu, the marquis de la Fare, marshal Villars, the grand prior of Vendome, the prince of Conti, and others. Here he caught the tone of polished society which distinguishes his writings, and which greatly contributed to his influence. His father was displeased with his mode of life, and entreated the marquis of Chateauneuf, French minister to Holland, to take the young Voltaire with him as a page. He consented; but Voltaire fell in love with the daughter of madame Noyer, a refugee in Holland, and was therefore sent back to his family. His father would receive him into favor again only on condition of his resuming the study of the law. A friend of his father, monsieur Caumartin, at length released him from the necessity of pursuing this study, by offering
him a quiet residence on his estate, where Voltaire became intimate with the elder Caumartin, who awakened in him a greatadmiration of Henry IV, and of Sully, and gave him a lively idea of the court of Louis XIV. Hence originated the Henriade and the Siècle de Louis XIV In 1716, he was imprisoned in the Bastile, on the charge of having written a satire against the government. He remained in confinement a year and a half, and, in this situation, planned a poem upon the league, the result of which was the Henriade. He likewise improved his tragedy Edipus, which was brought upon the stage in 1718, and was performed forty-five times in one year. Meanwhile, the poet had been released from prison in consequence of the real author of the satire having disclosed himself, but had been banished from Paris. Now, however, in consequence of the regent, the duke of Orleans, being delighted with the Edipus, he was allowed to return. His father himself was so much pleased with the representation of this play, that he embraced his son with tears in his eyes, and from. this time left him to his own inclination Voltaire now fell passionately in love with? the marchioness of Villars, so that his attention was withdrawn, for a time, from poetry; but, having recovered from this passion, he wrote the_play_of Artémire which was unsuccessful. It was afterwards brought upon the stage, in 1725 under the name of Marianne, when it met with much applause, and was often repeated. In 1722, he accompanied madame de Rupelmonde to Brussels, where he became acquainted with Jean Baptiste Rousseau; but the characters of the two were so different, that their acquaintance terminated in a complete separation. In 1723, Voltaire was engaged in completing the Henriade, which, about this period, appeared for the first time in London, under the name of the League, but without the consent of Voltaire, and in a very imperfect state. The president Hénault, and, other friends, disturbed him so much by their criticisms upon this production, that he threw it into the fire. Hénault snatched it out, with these words: "Your poem is like your hero: notwithstanding his faults, he was a great king, and the best of men." In 1726, Voltaire was again imprisoned, at the age of thirty-two years, in the Bastile. He had offended the chevalier de Rohan, a proud young nobleman, who, in consequence, caused him to be beaten by his servant. Voltaire now learned to fence, and challenged the