AVENARIUS, RICHARD HEINRICH LUDWIG (1843-1896), German philosopher, was born in Paris on the 19th of November 1843. His education, begun in Zürich and Berlin, was completed at the university of Leipzig, where he graduated in 1876. In 1877 he became professor of philosophy in Zürich, where he died on the 18th of August 1896. At Leipzig he was one of the founders of the Akademisch-philosophische Verein, and was the first editor of the Vierteljahrsschrift für wissenschaftliche Philosophie. In 1868 he published an essay on the Pantheism of Spinoza. His chief works are Philosophie als Denken der Welt gemäss dem Princip des kleinsten Kraftmasses (1876) and the Kritik der reinen Erfahrung (1888-1890). In these works he made an attempt to co-ordinate thought and action. Like Mach, he started from the principle of economy of thinking, and in the Kritik endeavoured to explain pure experience in relation to knowledge and environment. He discovers that statements dependent upon environment constitute pure experience. This philosophy, called Empirio-criticism, is not, however, a realistic but an idealistic dualism, nor can it be called materialism.
See Wundt, Philos. Stud. xiii. (1897); Carstanjen and Willy in Zeitsch. f. wiss. Philos. xx. (1896), 361 ff.; xx. 57 ff.; xxii. 53 ff.; J. Petzoldt's Einführung in d. Philos. d. reinen Erfahrung (1900).
AVENGER OF BLOOD, the person, usually the nearest kinsman of the murdered man, whose duty it was to avenge his death by killing the murderer. In primitive societies, before the evolution of settled government, or the uprise of a systematized criminal law, crimes of violence were regarded as injuries of a personal character to be punished by the sufferer or his kinsfolk. This right of vengeance was common to most countries, and in many was the subject of strict regulations and limitations. It was prevented from running into excesses by the law of sanctuary (q.v.) and in many lands the institution of blood-money, and the wergild offered the wrong-doer a mode of escaping from his enemies' revenge. The Mosaic law recognized the right of vengeance, but not the money-compensation. The Koran, on the contrary, while sanctioning the vengeance, also permits pecuniary commutation for murder.
AVENGERS, or Vendicatori, a secret society formed about 1186 in Sicily to avenge popular wrongs. The society was finally suppressed by King William II., the Norman, who hanged the grand master and branded the members with hot irons.
AVENTAIL, or Avantaille (O. Fr. esventail, presumably from a Latin word exventaculum, air-hole), the mouthpiece of an old-fashioned helmet, movable to admit the air.
AVENTINUS (1477-1534), the name taken by Johann Turmair, author of the Annales Boiorum, or Annals of Bavaria, from Aventinum, the Latin name of the town of Abensberg, where he was born on the 4th of July 1477. Having studied at Ingolstadt, Vienna, Cracow and Paris, he returned to Ingolstadt in 1507, and in 1509 was appointed tutor to Louis and Ernest, the two younger sons of Albert the Wise, the late duke of Bavaria-Munich. He retained this position until 1517, wrote a Latin grammar, and other manuals for the use of his pupils, and in 1515 travelled in Italy with Ernest. Encouraged by William IV., duke of Bavaria, he began to write the Annales Boiorum, about 1517, and finishing this book in 1521, undertook a German version of it, entitled Bayersche Chronik, which he completed some years later. He assisted to found the Sodalitas litteraria Angilostadensis, under the auspices of which several old manuscripts were brought to light. Although Aventinus did not definitely adopt the reformed faith, he sympathized with the reformers and their teaching, and showed a strong dislike for the monks. On this account he.was imprisoned in 1528, but his friends soon effected his release. The remainder of his life was somewhat unsettled, and he died at Regensburg on the 9th of January 1534. The Annales, which are in seven books, deal with the history of Bavaria in conjunction with general history from the earliest times to 1460, and the author shows a strong sympathy for the Empire in its struggle with the Papacy. He took immense pains with his work, and to some degree anticipated the modern scientific method of writing history. The Annales were first published in 1554, but many important passages were omitted in this edition, as they reflected on the Roman Catholics. A more complete edition was published at Basel in 1580 by Nicholas Cisner. Aventinus, who has been called the "Bavarian Herodotus," wrote other books of minor importance, and a complete edition of his works was published at Munich (1881-1886). More recently a new edition (six vols.) has appeared.
See T. Wiedemann, Johann Turmair gen. Aventinus (Freising, 1858); W. Dittmar, Aventin (Nördlingen, 1862); J. von Döllinger, Aventin und seine Zeit (Munich, 1877); S. Riezler, Zum Schutze der neuesten Edition von Aventins Annalen (Munich, 1886); F. X. von Wegele, Aventin (Bamberg, 1890).
AVENTURINE, or Avanturine, a variety of quartz containing spangles of mica or scales of iron-oxide, which confer brilliancy on the stone. It is found chiefly in the Ural Mountains, and is cut for ornamental purposes at Ekaterinburg. Some of the Siberian aventurine, like that of the vase given by Nicholas I. to Sir R. Murchison, in 1843, is a micaceous iron-stained quartz, of but little beauty. Most aventurine is of reddish brown or yellow colour, but a green variety, containing scales of fuchsite or chrome-mica, is also known. This green aventurine, highly valued by the Chinese, is said to occur in the Bellary district in India.
Aventurine felspar, known also as Sun-stone (q.v.) is found principally at Tvedestrand in south Norway, and is a variety of oligoclase enclosing micaceous scales of haematite. Other kinds of felspar, even orthoclase, may however also show the aventurine appearance. Both plagioclastic and orthoclastic aventurine occur at several localities in the United States.