in the West was going on between the secular and the ecclesiastical leaders of Europe, between the emperors and the popes, the latter made use of the convenient nickname as a handle to their designs. The partisans of the popes became Guelphs. Another reason is given for this transfer of a political badge from the parties in a family quarrel to great national divisions. The last heiress of the Bavarian Guelphs married a younger son of the house of Este, the most powerful family in eastern Lombardy, which, about the end of the twelfth century, became the head of the church party in their own district. The opposition raised by this faction to the Ghibeline, or Suabian emperors, transferred the two German names to Italy; and in the case of Otho IV., who was no other than the son of Henry the Lion, those names, with little regard to their family origin, signified no more, than that a Guelph espoused the side of the pope, a Ghibeline that of the emperor. Pope Innocent III. did, in fact, oppose Otho IV. of the Guelph family, by setting up as candidate for the imperial throne Frederick II. of Naples, who was of pure Ghibeline blood. Another explanation of the application of the terms is given, which makes Italy itself the scene of their origin. The great Countess Matilda, whose devotedness to Pope Gregory VII. made her hate the Emperor Henry IV. with all her heart, married Guelph of Bavaria, whose ungrateful return for imperial benefits had been rebellious war. From him, say some writers, the anti-imperial faction derived its name, while, according to the same authorities, that of its opponents did not originate till many years afterwards, on the birth of Henry VI. at Ghibelungen. Whatever uncertainty may rest upon the origin of these shibboleths of faction, there can be no doubt as to the intensity of feeling which they inspired.—R. H.
GUENEAU de Montbeillard, Philibert, an able French miscellaneous writer, born at Semur in Auxois in 1720. He wrote a "History and Memoirs of the Royal Academy of Sciences," 1770. He was afterwards induced by his friend Buffon to undertake the division of his great work devoted to birds; and so admirably was the work accomplished that few readers were aware of any division in the authorship, until it was announced by Buffon himself. He was likewise the author of the articles "Extension" and "Insects" in the Encyclopedie, and some other treatises. He died November 28, 1785.—G. BL.
GUENEE, Antoine, was born at Étampes in 1717. In 1741 he succeeded Rollin in the chair of rhetoric at the collége du Plessis, and held that office for twenty years. He travelled in Italy, Germany, and England. His chief work is "Lettres de quelques Juifs portugais, allemands et polonais à M. de Voltaire;" 1769, a production the merits of which Voltaire has acknowledged, directed though it was against himself. Guénée also translated into French some of our English writers on the evidences of christianity. He died in 1803.—W. J. P.
GUERCINO, Giovanni Francesco Barbieri, commonly called from his squint Guercino, was born at Cento, near Bologna, in 1592; hence his name of Il Guercino da Cento. He belongs to the class of self-taught geniuses, for his first occupation was tending his father's cart, when he went into the towns with supplies of faggots for the citizens. Guercino's talents were first developed at Bologna, where he was a follower, not a pupil, of the Carracci. He then went to Venice, and in the pontificate of Paul V. he even undertook a journey to Rome. The famous Caravaggio was then flourishing at Rome, and his bold style quite fascinated the young Bolognese painter, though he soon found that friendship was impossible with so wild and imperious a spirit as Caravaggio. Guercino established a great reputation at Rome, having found a valuable patron in Gregory XV.; but, after the death of that pope in 1623, he returned to his native place, Cento, where he established himself, until by the death of Guido in 1642 he was induced to settle in Bologna, where he lived prosperous and honoured until the year 1666, when he died in affluent circumstances. Guercino had three different styles; first he belonged to the school of the Tenebrosi, of which Caravaggio was the founder, and which is chiefly conspicuous for its dark forcible shadows; his second style was a modification of this, being in everything more refined and select; in his third he became an imitator of the delicate style of Guido, lost his own original power, and became insipid. He is distinguished from Guido in his best pictures by greater vigour and power of expression, and by generally a much greater force of shadow. His works, mostly in oil, are extremely numerous; his large altarpieces alone exceeding one hundred in number, at Cento, Bologna, Rome, Florence, Genoa, Ferrara, and other cities. His masterpiece is "Santa Petronilla" in the Capitol at Rome, originally painted for St. Peter's, but a mosaic of it is put up in its stead. The body of the saint is being deposited in the vault prepared for it in the Via Ardeatina, outside the walls of Rome; above is seen a vision of our Saviour, with angels receiving the soul of the saint.—Guercino's brother, Paolo Antonio Barbieri, was a good painter of animals, flowers, &c. He died in 1649.—(Calvi, Notizia della vita, &c., di G. F. Barbieri, 1808.)—R. N. W.
GUERET, Gabriel, a celebrated French lawyer, born at Paris in 1641; died in 1688. He was one of the associated compilers of Le Journal du Palais. His best known works are "Le Parnassus Reformé;" "La Guerre des Auteurs;" "La Carte de la Cour;" "La Promenade de St. Cloud, ou dialogues sur les auteurs;" "Arrêts Notables du Parlement."
GUERIKE, Otto von, inventor of the air-pump, and constructor of the first electrical machine, was born at Magdeburg on the 20th November, 1602. Having studied law at Leipsic and mathematics at Leyden, particularly applying himself to geometry and mechanics, he visited France and England, and afterwards resided for some time as a master engineer at Erfurt. In 1627 he was elected a member of the senate, and subsequently burgomaster, of his native city. While discharging the duties of these important offices, Guerike devoted much of his time to scientific pursuits; and as the weight and materiality of the air was at that time a recent discovery, which naturally excited much interest (see Torricelli), his mind became strongly impressed with the subject, and he conceived the idea of endeavouring to construct a machine by which he might be able to create an absolute vacuum. His first attempts consisted in filling close cylindrical vessels with water, which he endeavoured to extract by means of a pump, without admitting air; but in this he was unsuccessful. He then constructed a hollow copper sphere, provided with two orifices, to one of which a stopcock was fitted, and to the other a pump for the purpose of exhausting the air directly, without the intervention of any liquid. The success of this novel experiment was announced by the rush of air into the globe, which was observed on turning the stopcock, after having operated the piston for some minutes. This was the first air-pump; and Guerike, having much improved its construction, so as to bring it into a shape much more nearly resembling its present form, had the honour of exhibiting it in 1654 in presence of the Emperor Ferdinand III. and several of the German princes assembled at the diet of Ratisbon. About the same time he invented also the small apparatus, so useful in illustrating the pressure of the atmosphere, known as the "Magdeburg hemispheres." In further prosecution of the same subject, he constructed, against the wall of his house, a water-barometer, in which floated a diminutive human figure to indicate the level of the liquid as it rose and fell with the varying weight of the atmosphere.
Guerike's electrical machine consisted of a globe of sulphur, cast in a glass sphere, which was afterwards broken in order to remove the sulphur globe, although the glass itself, if fitted on an axis, would have served the purpose better. With this rude machine, however, Guerike excited much greater quantities of electricity than had previously been produced, and he was thus enabled not only to see flashes of light, but to hear, for the first time, the snapping noise of the electric spark. In the words of Humboldt, "he heard the first sound, and saw the first light, in artificially-produced electricity." He discovered also the property of electro-repulsion. In 1681 he resigned the municipal office which he had held at Magdeburg for a period of thirty-five years, and went to reside with his son at Hamburg, where he died in 1686. His principal experiments and observations are recorded in a work which he left behind him, entitled "Experimenta nova Magdeburgica de vacuo spatio."—G. BL.
GUERIN, Pierre Narcisse, a distinguished French painter, was born in Paris in 1774, and studied painting under Regnault. He became an imitator of David, but refined upon the manner of that eminent painter, carrying David's antique taste to the utmost precision and delicacy, so that his figures have painfully the appearance of painted antique statues or bassi-relievi, or figures even in ivory and gold. Guerin first attracted notice in 1798 by a picture—"Marcus Sextus, having escaped the proscriptions of Sulla, returns, and finds his daughter weeping by the side of her dead mother." In 1808 he exhibited his great picture now at Versailles, of the "Révoltés du Caire," or Bona-
