een
France and Spain. They are highest in the centre, Mount Maladetta
reaching 11,168 ft. The snow-line is about 8000 or 9000 ft., and there
are glaciers on the French side. Valleys run up either side, ending in
precipitous "pot-holes," with great regularity. The passes are very
dangerous from wind and snow storms. The streams to the N. feed the Adour
and Garonne; those to the S., the Ebro and Douro. Vegetation in the W. is
European, in the E. sub-tropical. Minerals are few, though both iron and
coal are worked. The basis of the system is granite with limestone strata
superimposed.

PYROXYLINE, an explosive substance obtained by steeping vegetable
fibre in nitro-sulphuric acid and drying after it is washed.

PYRRHA, in Greek mythology the wife of DEUCALION (q. v.).

PYRRHIC DANCE, the chief war-dance of the Greeks, of quick, light
movement to the music of flutes; was of Cretan or Spartan origin. It was
subsequently danced for display by the Athenian youths and by women to
entertain company, and in the Roman empire was a favourite item in the
public games.

PYRRHO, the father of the Greek sceptics, born in Elis, a
contemporary of Aristotle; his doctrine was, that as we cannot know
things as they are, only as they seem to be, we must be content to
suspend our judgment on such matters and maintain a perfect
imperturbability of soul if we would live to any good.

PYRRHONISM, philosophic scepticism. See PYRRHO.

PYRRHUS, king of Epirus, and kinsman of Alexander the Great; essayed
to emulate the Macedonian by conquering the western World, and in 280 B.C.
invaded Italy with a huge army, directed to assist the Italian Greeks
against Rome; in the decisive battles of that year and the next, he won
"Pyrrhic victories" over the Romans, losing so many men that he could not
pursue his advantage; 278 to 276 he spent helping the Greek colonies in
Sicily against Carthage; his success was not uniform, and a Carthaginian
fleet inflicted a serious defeat on his fleet returning to Italy; in 274
he was thoroughly vanquished by the Romans, and retired to Epirus;
subsequent wars against Sparta and Argos were marked by disaster; in the
latter he was killed by a tile thrown by a woman (318-272 B.C.).

PYRRHUS, called also NEOPTOLEMUS, son of Achilles; was one of
the heroes concealed in the wooden horse by means of which Troy was
entered, slew Priam by the altar of Zeus, and sacrificed Polyxena to the
manes of his father. An