POSEN 322 POSITIVE PHILOSOPHY /era, and Demeter, he was regarded as only inferior in power to Zeus. His usual residence was in the depths of the sea near JEgse, in Euboea, and the attri- butes ascribed and most of the myths re- garding him have reference to the phe- nomena of the sea. The horse, and more particularly the war horse, was sacred to Poseidon, and one of the symbols of his power. During the Trojan War Po- seidon was the constant enemy of Troy, and after its close he is described as thwarting the return of Ulysses to his home for his having killed Polyphemus, a son of the god. Poseidon was married to Amphitrite. His worship was com- mon throughout Greece and the Greek colonies, but especially prevailed in the maritime towns. The Isthmian games were held in his honor. In works of art Poseidon is represented with features re- sembling those of Zeus, and often bears the trident in his right hand. A com- mon representation of him is as drawn in his chariot over the surface of the sea by hippocamps (monsters like horses in front and fishes behind) or other fabulous animals. POSEN, a province in eastern Europe which prior to the World War belonged to the German Empire, but which by the treaty of Versailles in 1919 Germany ceded to the new Polish state. Its area is 11,184 square miles and its estimated population is over two millions. Even before its cession to Poland the major- ity of its inhabitants were Poles and spoke the Polish language, in spite of the vigorous repressive measures adopted by the German Government. Almost sev- enty-five per cent, of the population be- long to the Roman Catholic Church. Posen until 1793 formed a part of Po- land; the treaty of Versailles merely restored it to its rightful owner. The population is engaged chiefly in agri- culture, less than twenty-five per cent, being employed in the factories. The chief products are the grains, rye, wheat, oats, and barley. The principal indus- try is the manufacture of spirituous liquors. POSEN, a fortified town formerly be- longing to Prussia, now to Poland, capi- tal of the province of the same name and an archbishop's see, stands on the Warthe, 149 miles E. by S. of Berlin. It is surrounded by two lines of forts, is built with considerable regularity, has generally fine wide streets, and numerous squares or open spaces. The most note- worthy public buildings are the cathe- dral, in the Gothic style (1775), the town parish church, a fine building in the Italian style, both Roman Catholic; the town house (1508), with a lofty tower; the Raczynski Library; the municipal archive building, etc. The manufaC' tures consist chiefly of agricultural ma- chines, manures, woolen and linen tis- sues, carriages, leather, lacquerware, etc. There are also breweries and distilleries. Pop. about 175,000. POSES PLASTIQUES, or TABLEAUX VIVANTS, imitations of pictures by liv= ing persons taking the place of those depicted. POSIDONIUS, a Greek Stoic philoso- pher; born in Apamea, Syria, but styled "The Rhodian" by reason of his long resi- dence in the island of Rhodes ; lived from 135 to 50 B. c. He was one of the most learned men of antiquity, his knowledge and his writings extending over every branch of science. His greatest work was a universal history in 52 books, held in high esteem by the ancients; it was a continuation of Polybius, and covered the period 145-82 B. c. His lectures on "Tactics" would seem to be the basis of the tractate of his disciple Asclepiodotus on the same subject. POSILIPO, a mountain of Italy, on the N. W. of Naples, close by the city, from of old a noble site for the villas of wealthy citizens. It is remarkable for the tunnel known as the Grotto of Posi- lipo, through which the road from Naples to Pozzuoli passes. The grotto varies in height from 20 feet to 80 or more, is 20 to 30 feet vnde, and 755 yards long. It is traditionally said to have been made in the reign of Augustus, but is prob- ably earlier. Above the eastern arch- way of the grotto is the so-called "Tomb of Vergil." At the base of the hill an- ciently stood the poet's villa. During tl :e Middle Ages the common people believed the grotto to be the work of the poet, whom they regarded as a great ma- gician. Two other tunnels penetrate through the hill, one to the N. of the grotto, 800 yards long, 39 feet high, and 33 feet broad, made for the tramway, and another constructed at the command of Agrippa in 37 B. c, but only discov- ered in 1812. POSITIVE, in photography, a picture obtained by printing from a negative, in which the lights and shades are rendered as they are in nature. See Photog- raphy. POSITIVE PHILOSOPHY, the system of philosophy outlined by Auguste Comte (1798-1857) in his "Philosophie Posi- tive," the sixth and last volume of which was published in 1842. It is the out- come of the Law of the Three Stages and is based on the positive sciences, taken in the following series: mathe-
